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Cement grouting has been widely used in rock tunneling to reduce groundwater inflow by sealing rock fractures. However, the injected cement grout often encounters hydraulic erosion that affects the safety and sustainability of rock tunnels in the long term. Analysis of the long-term hydraulic erosion effect on cement grout in rock fractures is therefore important for the safety and sustainability development of rock tunnel engineering. In this work, a hydraulic erosion model for analyzing cement grout erosion in a homogeneous fracture is established and used to theoretically investigate the transmissivity evolution of the grouted fracture under longterm hydraulic erosion. In the present model, the fracture seepage characteristics, solid erosion theory and mass conversation for water-solid two-phase flow are considered, and the mathematical model as a set of partial differential equations is established. Based on laboratory tests, the key parameters (e.g., erosion coefficient) are calibrated and the erosion model is validated. Numerical simulations are conducted by numerically resolving the mathematical model. The results show that the erosion phenomenon first occurs in the edge areas of the grouted area near the fracture boundary; the erosion area gradually expands toward the center of the grouted area. The porosity and flow velocity significantly increase in the area with relatively strong erosion effects. During the erosion process, the concentration of cement grout gradually increases along the seepage path until a more uniform distribution of cement particle concentration is achieved. Due to the erosion process, the spatial distribution of hydraulic pressure along the fracture direction transforms from a linear distribution to a nonlinear distribution. The effective fracture transmissivity increases nonlinearly along the erosion process. The presented erosion model and analysis results are potentially useful for the safety and durability assessment of rock tunne, QC 20240624Part of ISBN 978-103280042-4

The grout propagation plays a crucial role in the design of polyurethane grouting for reinforcing and sealing fractured rock. Understanding the influence of isocyanate index on the diffusion process is essential for selection and material modification to improve the grouting effectiveness. In this study, a numerical method was developed to simulate the grout propagation of polyurethane, considering the coupled of reaction kinetics and fluid flow. Furthermore, the influence of the isocyanate index on pressure, diffusion distance, component conversion and density were analyzed. These findings contribute to the preparation and selection of polyurethane grout for practical engineering applications., QC 20240624Part of ISBN 978-103280042-4

Cement grouting is widely used in rock tunnelling to control groundwater inflow by sealing rock fractures. Accurately predicting grout propagation in rock fractures is crucial for the design, execution, and monitoring of rock grouting in engineering applications. Current methods rely on theoretical models, such as the real-time grouting control (RTGC) method, which is derived based on simplified fracture geometries like smooth parallel plates/disks. However, real rock fractures consist of rough surfaces with variable apertures. In this study, we present a computational model for theoretically predicting the propagation of non-Newtonian cement grout in variable fracture apertures. This model is validated with laboratory test data on grout propagation in a one-dimensional varying aperture long slot (VALS). We also analysed the impact of varying aperture on cement grout propagation processes. Our findings demonstrate that the presented computational model predicts the grout propagation process in this geometry with good accuracy. Moreover, we observed that varying aperture significantly affects the grout propagation process in fractures. The insights provided by our model and analysis results are potentially useful in rock tunnelling projects, specifically for the theoretical analysis of cement grout propagation in rock fractures., QC 20240626Part of ISBN 978-103280042-4

Nowadays, the use of Tunnel Boring Machines (TBM) in tunnelling has increased in urban environments. One of the effective parameters in the excavation process is the use of grout behind the segments to prevent ground settlement and penetration into the tunnel. The investigation of the effects of two-component grout (bentonite and sodium silicate) on the mechanical properties of the grout plays a crucial role in mechanized excavation. Therefore, this article aims to investigate the effect of various parameters on the properties of the two-component grout. Eight different mixing designs were considered in this research. Gel-time tests, viscosity test, water bleeding test, uniaxial compressive strength tests (UCS), and direct shear tests were conducted for each mixing design. The UCS tests were performed for eight mixing designs and at four different ages of the grout, while the direct shear test was conducted for five mixing designs at the age of one day. The results showed that increasing the sodium silicate content from 4% to 9.4% reduced the Gel-time to 7 seconds, and increasing the bentonite content from 2.3% to 4.58%, increased the marsh funnel time to 12 seconds. The uniaxial compressive strength of the grout increased to 0.682 MPa at the age of 28 days. Finally, by conducting the direct shear test on the grout and obtaining the parameters of cohesion and internal friction angle, it was determined that these two parameters depend on the values of bentonite and sodium silicate, and they change with the increase or decrease of these grout components., Danas je u tunelogradnji u urbanim sredinama znatno porasla upotreba strojeva za bušenje tunela (TBM). Jedan od najučinkovitijih parametara iskapanja prilikom korištenja ovih vrsta strojeva jest upotreba smjese za injektiranje pozadine tunelskih segmenata kako bi se spriječilo slijeganje tla i prodiranje u tunel. Ispitivanje utjecaja dvokomponentne injektne smjese (bentonit i natrijev silikat) na njezina mehanička svojstva igra ključnu ulogu pri strojnome iskopu. Stoga je cilj ovoga članka istražiti utjecaj različitih parametara na svojstva dvokomponentne smjese koja se koristi za injektiranje pozadine tunelskih segmenata. U ovome istraživanju razmatrano je osam različitih načina miješanja. Tijekom istraživanja za svaki način miješanja provedeni su testovi vremena geliranja, testovi viskoznosti, određivanje izdvajanja vode, testovi jednoosne tlačne čvrstoće (UCS) i testovi izravnoga smicanja. Ispitivanja jednoosne tlačne čvrstoće provedena su za osam načina miješanja i pri četiri različita vremena starosti smjese (2 sata, 1 dan, 7 dana i 28 dana), dok je ispitivanje izravnoga smicanja provedeno za pet načina miješanja starosti 1 dan. Rezultati provedenih ispitivanja pokazali su da je povećanje udjela natrijeva silikata s 4 % na 9,4 % smanjilo vrijeme geliranja na 7 sekundi, a povećanje udjela bentonita s 2,3 % na 4,58 % povećalo vrijeme viskozimetra na 12 sekundi. Jednoosna tlačna čvrstoća smjese za injektiranje porasla je na 0,682 MPa u vremenu od 28 dana. Na kraju, provođenjem ispitivanja direktnoga smicanja na smjesi i dobivanjem parametara kohezije i kuta unutarnjega trenja utvrđeno je da ova dva parametra ovise o vrijednostima bentonita i natrijeva silikata, a mijenjaju se s povećanjem ili smanjenjem komponenata smjese.

The construction of infrastructures such as dams requires for the foundations to lay on stable ground. One way to do so is to grout the rock fractures present in the bedrock using concrete, and this also ensures that lower amounts of groundwater reach the infrastructure itself. However, the continuous flow of groundwater carrying various dissolved chemical compounds, will trigger over time the deterioration of the concrete grout by dissolving the mineral phases resulting from the hydration process. This study aims at determining the variations in porosity and hydraulic conductivity induced by the dissolution of portlandite content present in the grout following the groundwater flow. Eight different cases have been simulated in COMSOL Multiphysics®, based on various combinations of fracture geometry (rough and smooth), hydraulic gradient, and inflowing groundwater composition. Each model has two main components, one for the flow simulation and one for the reactive transport. The modules implemented from COMSOL Multiphysics® are Darcy’s Law, Chemistry, and Transport of Diluted Species in Porous Media. The software PHREEQC has been used to determine the chemical species concentration for both the initial and boundary conditions. The results show that, at the end of a 100-day period, the mineral concentration decreases from 56.27% to 61.27% depending on the simulation considered. This leads to an increase in porosity ranging from 1.94% to 2.23%, while hydraulic conductivity displays a minimum growth of 6.42% and a maximum of 7.43%. The sensitivity analysis results reveal that the most influencing factor on the degradation is the hydraulic gradient, which is followed by the fracture geometry, while the inflowing groundwater composition impact is not as high as the previous ones., Byggandet av infrastrukturer som dammar kräver att grunden läggs på stabil mark. Ett sätt att uppnå detta är att fylla sprickor i berggrunden med betong, vilket också säkerställer att mindre mängder grundvatten når infrastrukturen. Det kontinuerliga flödet av grundvatten, som bär med sig olika lösta kemikalier, kan dock med tiden leda till att betongen bryts ner genom att mineralfaserna som bildas vid hydratiseringsprocessen löses upp. Denna studie undersöker hur porositeten och den hydrauliska ledningsförmågan förändras när portlandit i betongfogar löses upp av grundvattenflödet. Åtta olika scenarier har simulerats i COMSOL Multiphysics® med olika kombinationer av sprickgeometri (grov och slät), hydraulisk gradient och inkommande grundvattensammansättning. Varje modell består av två huvuddelar: en för flödessimulering och en för reaktiv transport. Modulerna från COMSOL Multiphysics® som används är Darcys lag, kemi och transport av utspädda ämnen i porösa medier. Programvaran PHREEQC har använts för att fastställa koncentrationen av kemiska ämnen för både initiala och gränsvillkor. Resultaten visar att efter 100 dagar minskar mineralkoncentrationen med mellan 56,27% och 61,27%, beroende på simuleringen. Detta leder till en ökning av porositeten med 1,94% till 2,23%, medan den hydrauliska ledningsförmågan ökar med minst 6,42% och högst 7,43%. Känslighetsanalysen visar att den hydrauliska gradienten är den mest påverkande faktorn för nedbrytningen, följd av sprickgeometrin. Sammansättningen av det inkommande grundvattnet har inte lika stor påverkan.

Rock grouting is a common measure to reduce the seepage through conductive fractures in the rock mass around tunnels. Two types of grouting are normally carried, pre-excavation grouting and postexcavation grouting. Pre-grouting, commonly applied in Scandinavian tunnels, is used to seal the conductive fractures around the tunnel before the excavation of tunnel sections. In post-excavation grouting, which is dedicated to seal the remaining leakage in the excavated tunnel sections, the injected grout often encounters large seepage in rock fractures. Previous experiments have shown that the grout can be washed out easily when the grout is fresh even though the injected grout has initially sealed the fracture. One of the most significant phenomena for the water to “break up” the grout is viscous fingering. Viscous fingering occurs when certain conditions enable interface instability between the water and the cement-based grout. In this paper, the authors aim to evaluate if viscous fingering can be avoided under pre- and post-grouting conditions. For this purpose, computational fluid dynamics (CFD) simulations using the software Ansys Fluent is carried out. The simulation results demonstrating viscous fingering between water and cement-based grout are analyzed and discussed. Based on the results, suggestions on the grouting strategy with respect to pre- and post-grouting are provided to deal with the potential issues related to viscous fingering., QC 20240624Part of ISBN 978-103280042-4

Polyurethane grouting is an important technical solution used for seepage prevention and mechanical reinforcement of fractured rock. Various components of polyurethane grout significantly affect the grout properties and propagation behavior. The present study focuses on the crucial role of component parameters in controlling the propagation process and designing grouting parameters for foaming polyurethane grout. A coupled modeling approach combining chemical reactions and flow field analysis is developed to investigate the polyurethane foaming process. The proposed modeling approach is validated by comparing simulation results with experimental data from the literature. The influence of key component parameters: isocyanate index, initial water concentration and physical blowing agent, on the propagation characteristics (including propagation distance, maximum pressure, final density, reaction time and maximum temperature) of foaming polyurethane grout in rock fractures are further analyzed. The results reveal two distinct types of effects caused by the components, i.e., a monotonic relationship and a parabolic trend. Critical values are identified for the impact of isocyanate index on maximum propagation distance, final density and characteristic time, as well as for the influence of physical blowing agent on maximum propagation distance, final density and maximum pressure. Other parameters demonstrated a monotonic relationship. Additionally, a quantitative assessment is conducted to evaluate the impact of multiple components on propagation characteristics. The finding indicates that the initial water concentration has a significant effect on all properties, while isocyanate index exerts a more pronounced impact on reaction time and maximum temperature. The effect of the physical blowing agent is relatively minor compared to other factors. This study is helpful for material selection and proportioning of polyurethane grout in practical engineering applications., QC 20240506

Ultra-fine blast-furnace slag binders have recently been introduced to repair masonry. The reduced particle diameter of these binders makes them especially suitable for use as grouts, since this characteristic enables these grouts to fill even the smallest voids. The current necessity and effectiveness of Finite Element Analysis in any process concerning construction, repair or reinforcement of building structures remains unquestionable. In this way, the calibration of Finite Element material models for their correct performance has become compulsory. Regarding quasi-brittle materials, such as mortar and grouts, the Microplane model is recommended to reproduce their behaviour. This paper is targeted towards obtaining Microplane model coefficients to exactly reproduce the behaviour of ultrafine blast-furnace slag grout samples. To this end, several compressive tests have been carried on in order to obtain the experimental stress–strain curves that define the behaviour of these samples. Furthermore, reverse engineering by means of an optimisation algorithm successfully attained the possible coefficients to reproduce this material with the Microplane model. The correctness of these coefficients has been verified with a new campaign composed of compressive tests, Double Punch tests, and flexural tests. These tests have been reproduced by Finite Element Analysis, thereby confirming the accuracy of the set of coefficients. Thus, two are the main conclusions obtained: (1) the framework for the modelling of ultra-fine blast-furnace slag grout elements based-on the Microplane model has been proposed, implemented and validated; and (2) a value for the coefficients of the abovementioned model has been proposed.

Low-pressure injection of nanosilica aqueous suspensions is often adopted to either waterproof or increase the liquefaction resistance of granular soils. The basic principle behind this ground improvement technique consists in filling the soil pores with a low-viscosity fluid that changes its consistency with time, first into a gel, then into a solid. From an application point of view, the simulation of the time-dependent permeation process is crucial to relate the in situ distance covered by the grout to the operational parameters. A comprehensive investigation was performed, combining laboratory experiments with theoretical approaches, to characterize the phenomenon and then derive predictive relations useful for designing treatment executions. The time-dependent rheological properties of different nanosilica aqueous suspensions were first quantified by means of rheometric tests, then described with Bingham's law. Grout permeation in granular media was then simulated by suitably modifying Darcy's law to incorporate the temporal evolution of Binghamian grout rheology. After validating the modified Darcy's law employment for nanosilica grout flows with respect to laboratory experimental data, simplified analytical equations, capable of predicting the temporal evolution of the distance covered in situ by the grout and the flow rate-injection pressure relation, are provided.

The construction of infrastructures such as dams requires for the foundations to lay on stable ground. One way to do so is to grout the rock fractures present in the bedrock using concrete, and this also ensures that lower amounts of groundwater reach the infrastructure itself. However, the continuous flow of groundwater carrying various dissolved chemical compounds, will trigger over time the deterioration of the concrete grout by dissolving the mineral phases resulting from the hydration process. This study aims at determining the variations in porosity and hydraulic conductivity induced by the dissolution of portlandite content present in the grout following the groundwater flow. Eight different cases have been simulated in COMSOL Multiphysics®, based on various combinations of fracture geometry (rough and smooth), hydraulic gradient, and inflowing groundwater composition. Each model has two main components, one for the flow simulation and one for the reactive transport. The modules implemented from COMSOL Multiphysics® are Darcy’s Law, Chemistry, and Transport of Diluted Species in Porous Media. The software PHREEQC has been used to determine the chemical species concentration for both the initial and boundary conditions. The results show that, at the end of a 100-day period, the mineral concentration decreases from 56.27% to 61.27% depending on the simulation considered. This leads to an increase in porosity ranging from 1.94% to 2.23%, while hydraulic conductivity displays a minimum growth of 6.42% and a maximum of 7.43%. The sensitivity analysis results reveal that the most influencing factor on the degradation is the hydraulic gradient, which is followed by the fracture geometry, while the inflowing groundwater composition impact is not as high as the previous ones., Byggandet av infrastrukturer som dammar kräver att grunden läggs på stabil mark. Ett sätt att uppnå detta är att fylla sprickor i berggrunden med betong, vilket också säkerställer att mindre mängder grundvatten når infrastrukturen. Det kontinuerliga flödet av grundvatten, som bär med sig olika lösta kemikalier, kan dock med tiden leda till att betongen bryts ner genom att mineralfaserna som bildas vid hydratiseringsprocessen löses upp. Denna studie undersöker hur porositeten och den hydrauliska ledningsförmågan förändras när portlandit i betongfogar löses upp av grundvattenflödet. Åtta olika scenarier har simulerats i COMSOL Multiphysics® med olika kombinationer av sprickgeometri (grov och slät), hydraulisk gradient och inkommande grundvattensammansättning. Varje modell består av två huvuddelar: en för flödessimulering och en för reaktiv transport. Modulerna från COMSOL Multiphysics® som används är Darcys lag, kemi och transport av utspädda ämnen i porösa medier. Programvaran PHREEQC har använts för att fastställa koncentrationen av kemiska ämnen för både initiala och gränsvillkor. Resultaten visar att efter 100 dagar minskar mineralkoncentrationen med mellan 56,27% och 61,27%, beroende på simuleringen. Detta leder till en ökning av porositeten med 1,94% till 2,23%, medan den hydrauliska ledningsförmågan ökar med minst 6,42% och högst 7,43%. Känslighetsanalysen visar att den hydrauliska gradienten är den mest påverkande faktorn för nedbrytningen, följd av sprickgeometrin. Sammansättningen av det inkommande grundvattnet har inte lika stor påverkan.

An embankment dam can be damaged by internal erosion. During this process, the soil material erodes and is transported out of the dam structure. Some common types of damage due to internal erosion are piping, less dense soil zones, and zones where the fine material has been washed out. To prevent ongoing internal erosion from developing into a damage or a breach, injection grouting may be performed to replace the eroded soil material. In an embankment dam, injection grouting is usually performed vertically. A pipeline is drilled from the crest of the dam to the damaged zone, to which the grout material is delivered via a pump. The injection grouting methods suitable for embankment dams are compaction and permeation grouting. In compaction grouting, a lowmobility grout material is injected at high pressure, compacting the surrounding soil. In permeation grouting, the injection pressure is lower and the grout material flows more easily, allowing it to permeate the porous structure of the soil into which it is injected. A grout material for embankment dams should have properties, i.e., particle size distribution, water content, shear strength, and bulk density, similar to those of the original core soil after injection. A grout material with these properties will however be very stiff and difficult to pump, and permeation will be difficult to achieve. Therefore, a new type of non-hardening grout material has been developed and tested in the laboratory. The grout material is a low-mobility grout, but its viscosity and yield strength can be temporarily lowered by replacing the fine aggregates with a limestone filler and by adding a superplasticizer. After injection, the effect of the superplasticizer wears off, leaving a grouted zone with geotechnical characteristics similar to those of the original core soil. The grout material consists of 0–4 mm aggregates, limestone filler, dry bentonite powder, water, superplasticizer, and an air-release agent. The grout material pro

Microencapsulated phase-change-materials (PCMs) incorporated in cementitious grout can be used as a source of energy in an underground thermal energy storage system. Differential scanning calorimetry (DSC) is a widely used technique to measure the latent heat or specific heat of PCM-embedded cementitious materials. However, using milligram sample sizes (as required by DSC) of a cementitious material fails to represent the actual scale of cementitious components. This is the reason why, in the present paper, non-isothermal heat conduction microcalorimetry (MC) was evaluated as a tool for determining the thermal properties of PCM-embedded grout as well as pure PCM (three PCMs were used). An MC experimental protocol (using both single and 5–6 temperature cycles) was developed and used to measure latent heat and melting and crystallization temperatures, which were in good agreement with those reported for pure PCMs by the producers. In addition, the specific heats of the PCM-containing grout also agreed with measurements using the hot disk technique. Overall, the results show that the MC technique can be used as a potential standard method in determining thermal processes in complex systems, such as in PCM-embedded cementitious systems, where a large sample size is needed to represent the material., QC 20230824

This paper attempts to reveal the influence of using fly ash in the grout on the axial bearing capacity of fully grouted rock bolts. For this purpose, different fly ash contents, including 1% and 2%, have been applied with Stratabinder HS with a water-to-grout ratio of 30%. Also, after preparing and curing the required samples, the UCS tests were conducted to determine the influence of fly ash on the grout strength. Along with the UCS tests, several pull-out tests were examined by preparing and curing rock bolt samples with steel reinforcement rebars of 16 mm and steel pipes with a 50 mm length and 23 mm diameter. The results revealed that replacing a small amount of grout with fly ash could increase the strength of the grout. Also, the axial bearing capacity has risen by using fly ash in the grout mixture.

Embankment dams may be damaged by internal erosion, which ultimately may lead to a failure. During internal erosion, finer soil particles from the core soil are being washed out. To restore the core function, injection grouting may be undertaken. Grouting the core of an embankment dam should be performed with a grout with similar characteristics as the original core soil. This grout type is commonly used in compaction grouting, e.g., a low mobility grout. The grout is similar to a fine-grained moraine core soil, but given its stiffness, it is difficult to permeate a damaged core soil. A modified low mobility grout containing sand, limestone filler, bentonite, plasticizer, air release agent and water has been tested in the laboratory with focus on permeation. Grouting was done in different sized aggregates. Impact of paste-to-aggregate ratio, grout consistency, maximum grain size of grout, coarseness of grouted material, and grouting methodology was tested. Higher paste-to aggregate ratios and lower viscosity/yield strength in/of the grout improved the permeation. Initially pressurized grouting compared to only hydrostatic pressures followed by stepwise pressure increased grouting was furthermore identified as a factor to improve the permeation., Validerad;2024;Nivå 2;2024-03-15 (hanlid);Funder: Svenskt Vattenkraftcentrum (SVC);Full text license: CC BY

Embankment dams can be damaged by internal erosion, which ultimately leads to a failure. When internal erosion occurs, finer soil particles from the core soil are washed out. To restore the function of the core, injection grouting can be undertaken. Grouting the core of an embankment dam should be performed with a grout material with characteristics similar to the core soil, such as a low-mobility grout. This type of grout material has similarities to a fine-grained moraine core soil given its stiffness, but it has difficulties permeating the damaged core soil. A modified low-mobility grout material containing gravel, sand, limestone filler, bentonite, plasticizer, air release agent, and water has been tested in the laboratory with focus on permeation. Injection was done on different-sized aggregates. The impact of paste-to-aggregate ratio, grout consistency, maximum grain size of grout material, particle size distribution of injected material, and injection method was tested. Higher paste-to-aggregate ratios, lower viscosity and lower yield strength of the grout material improved the permeation., QC 20230825

Embankment dams may be damaged by internal erosion, which ultimately may lead to a failure. During internal erosion, finer soil particles from the core soil are being washed out. To restore the core function, injection grouting may be undertaken. Grouting the core of an embankment dam should be performed with a grout with similar characteristics as the original core soil. This grout type is commonly used in compaction grouting, e.g., a low mobility grout. The grout is similar to a fine-grained moraine core soil, but given its stiffness, it is difficult to permeate a damaged core soil. A modified low mobility grout containing sand, limestone filler, bentonite, plasticizer, air release agent and water has been tested in the laboratory with focus on permeation. Grouting was done in different sized aggregates. Impact of paste-to-aggregate ratio, grout consistency, maximum grain size of grout, coarseness of grouted material, and grouting methodology was tested. Higher paste-to aggregate ratios and lower viscosity/yield strength in/of the grout improved the permeation. Initially pressurized grouting compared to only hydrostatic pressures followed by stepwise pressure increased grouting was furthermore identified as a factor to improve the permeation., Validerad;2024;Nivå 2;2024-03-15 (hanlid);Funder: Svenskt Vattenkraftcentrum (SVC);Full text license: CC BY

This paper attempts to reveal the influence of using fly ash in the grout on the axial bearing capacity of fully grouted rock bolts. For this purpose, different fly ash contents, including 1% and 2%, have been applied with Stratabinder HS with a water-to-grout ratio of 30%. Also, after preparing and curing the required samples, the UCS tests were conducted to determine the influence of fly ash on the grout strength. Along with the UCS tests, several pull-out tests were examined by preparing and curing rock bolt samples with steel reinforcement rebars of 16 mm and steel pipes with a 50 mm length and 23 mm diameter. The results revealed that replacing a small amount of grout with fly ash could increase the strength of the grout. Also, the axial bearing capacity has risen by using fly ash in the grout mixture.

The core soil of an embankment dam can be exposed to deteriorating processes, i.e., different kinds of internal erosion due to high hydraulic gradients, disadvantageous particle size distribu-tion, too coarse-grained filters or built-in defects. During internal erosion, fines from the core soil are washed out by the seepage, decreasing the impervious properties of the core. If the internal erosion process is discovered in time, drilling and grouting can be performed to stop the erosion. During drilling and grouting, eroded material from the core soil is replaced. In this paper, the methodology: “Identification – Localization – Characterization – Remediation” has been proposed. The methodology was tested on a large-scale embankment dam in a laboratory environment. The dam had a central core of moraine and was built inside a watertight concrete structure so a reservoir of water could be created upstream the dam. The left abutment of the dam had higher seepage rates than the rest of the dam and therefore had to be remediated. During the identification and localization phase, a 10 x 10 cm horizontal, high hydraulic conduc-tivity zone through the core soil was identified and localized at the left abutment at 1 m depth. During drilling at the abutment, it was found that the core soil beneath the damage had become more wet compared to when built. The remedial method used was compaction grouting with a new developed type of non-hardening grout material. The grouting pressures equaled the height of the vertical grout material column with an additional pressure of ~50 kPa to compensate for frictional losses during injection. The grout material was delivered via a novel pipe system where water and air were allowed to be drained. The seepage was lowered by 44 % directly after grout-ing and 60% four months after grouting.

Grout curtains are commonly constructed under dams to reduce the seepage through the rock foundation. In the design of grout curtains, empirical methods have mainly been used since the introduction of dam foundation grouting. Although empirical methods have been used with success in several projects, they have their limitations, such as poor control of the grout spread, only an indirect consideration of the threat of internal erosion of fracture infillings in the grouted zones, and the risk of hydraulic jacking. This paper presents a theory-based design methodology for grout curtains under dams founded on rock. In the design methodology, the grout curtain is designed as a structural component of the dam. The risk of erosion of fracture infilling material is explicitly accounted for along with the reduction of the hydraulic conductivity of the rock mass, and an optimization of the total uplift force. By applying the proposed design methodology, engineers can create a design better adapted to the prevailing geological and hydrogeological conditions in the rock mass, resulting in more durable grout curtains. The proposed methodology also enables cost and time estimates to be calculated for the grout curtain’s construction. Applying the principles of the observational method during the grouting execution also allows the design to be modified via predefined measures if the initial design is found to be unsuitable., QC 20220603

The liquid distribution of unsaturated wet granular media composed of granular materials and Newtonian fluid has been in detail studied. However, when a granular material is mixed with a certain amount of Bingham fluid, the effect of rheological properties of Bingham fluid on the deposition morphologies is not clearly explored. In this study, the adhesion rules of fresh cement grout flowing through granular materials without considering the filtration effect is investigated, and the deposition morphologies of cement grout in random packing of spheres is observed with the help of X-ray microtomography device. The results show that the deposition mechanism of cement grout is significantly dependent on its yield stress. The cement grout spontaneously forms open structures with large liquid–air interface. The morphologies of cement grout within cemented granular materials vary with grout content. With the increase of the yield stress of cement grout, neighbouring smaller clusters gradually touch each other and coalesce into more complex structure, and the largest cluster can contain almost all the cement grout.

This master thesis has investigated the performance of a deep excavation with a jet grout bottom plug used to prevent bottom heave and hydraulic uplift failure. The concept of a jet grout plug as a structural and sealing component in a specific case was studied, namely one of the tunnel sections of The West Link tunnel project in Gothenburg. The section was to be built as a cut-and-cover tunnel with the excavation shaft consisting of secant pile walls, struts and a jet grout bottom plug. It is to be established where there are a lot of sensitive buildings and constructions close to the excavation site. This makes it important not to disturb the surroundings during construction with, for example, settlements.The study was carried out by doing a literature study, analytical calculations and numerical simulations in the finite element software PLAXIS 2D. More specifically, the checks evaluated were uplift equilibrium of the jet grout plug and of the whole structure, structural performance of the jet grouted plug and hydraulic conductivity of the jet grouted mass.The results show a design of a jet grout plug that together with the additional structures works sufficiently enough to make a secure construction for a deep excavation below the ground water table. The structural performance of the jet grouted plug to function as a strut level is fulfilled even if the jet grout is not perfectly performed. To work as a sealing component the jet grout column pattern and the centre-to-centre distance between the columns are important factors together with the alignment and diameter of the jet grout columns. To make a completely watertight construction is however almost impossible in this case since the jet grout plug is located at a large depth (around 20 m). To work properly against failure by uplift it does not need to be completely watertight. Instead, the use of relief wells makes sure that the pore water pressure is not larger than the vertical stress from the soil, otherwis

Due to an increasing amount of aging tendencies in Swedish embankment dams, failures such as internal erosion has become a more common problem. Internal erosion is a phenomenon where certain soil material within the embankment dam is removed, often over a longer period of time. It is most common to occur at the inner core of the dam, and if it is allowed to continue for a longer time period the consequences can be disastrous. During the internal erosion, the inner material is washed out, creating larger voids and lowering the geotechnical stability of the dam. When larger voids start to appear, the seepage will increase allowing more material to be washed out and accelerating the process. In order to repair an embankment dam, exposed to inner erosion, it requires both the location of the faults as well as a suitable method of repairing. A method to repair internal erosion is by using grout and injecting it into the location of the fault. The knowledge regarding what type of grout and how it should be treated is today lacking. There are reasons to believe that a hardening mixture within an embankment dam using a till core will not cooperate well. For that reason, a grout with non-hardening properties is of interest. this thesis focuses on the Geomechanical strength parameters of two similar experimental non-hardening grouts. One with maximum grain size of 2 mm referred as grout 0/2, and one with maximum grain size of 4 mm, referred to as grout 0/4. The grouts consist of natural aggregates, calcium carbonate, water, bentonite, superplasticizer and defoamer. The grouts are evaluated by its undrained shear strength, water content, bulk- and dry density using fall cone tests and uniaxial compressive strength tests. To evaluate the grouts angle of friction and angle of dilatancy together with young’s modulus, consolidated, drained triaxial tests were performed. Three tests with different consolidation pressures (50, 150 and 300 kPa) were performed for each grout. Sinc, På grund av en ökad mängd med föråldrandetendenser hos svenska jordfyllningsdammar har brott så som inre erosion blivit ett alltmer vanligt problem. Inre erosion är ett fenomen där en viss jord inom jordfyllningsdammen är avlägsnad, generellt över en längre tidsperiod. Oftast inträffar detta vid den inre damkärnan och om erosionen är tillåten att fortskrida sig över en längre period kan konsekvenserna bli förödande. Inre erosion fungerar så att jordmaterial tvättas ut vilket skapar hålutrymmen och minskar den geotekniska hållfastheten för dammen. När större hålutrymmen bildats ökar läckaget som i sin tur tillåter mer material att bli urtvättat och processen blir accelererad. För att kunna reparera en jordfyllningsdam, utsatt för inre erosion, krävs både att platsen för brottet och metoden för att reparera är kända. En metod för att reparera inre erosion är genom att använda injektering och injektera hålutrymmet. Dock är kunskapen gällande vad för typ av injektering och hur den ska hanteras icke existerande i dagsläget. Det finns anledning att tro att ett härdande bruk inom en jordfyllningsdam, med en moränkärna, inte kommer samarbeta särskilt bra. På grund av det har ett bruk med icke-härdande egenskaper undersökt. Den här uppsatsen fokuserar på de geotekniska hållfasthetsegenskaperna för två liknande experimentella icke-härdande bruk. Ett med maximal kornstorlek på 2 mm benämnd som bruk 0/2 och ett med maximal kornstorlek på 4 mm, benämnd som bruk 0/4. Bruket består av natursand, kalciumkarbonat, vatten, bentonit, mjukgöringsmedel och skumdämpare. Bruken är utvärderade genom deras odränerade skjuvhållfasthet, vattenkvot, skrym- och torrdensiteten som har tagits fram från fallkorns-test och enaxiella trycktest (UCS). För att utvärdera brukens friktionsvinkel och dilationsvinkel tillsammans med styvheten (initiella och 50 %) har konsoliderat, dränerat triaxiala tests utförts. Tre test med varierande konsolideringstryck (50, 150 och 300 kPa) har utförts för båda bruk

Ever higher demands on the sealing of rock around underground structures drive the development of cement based grouts. The results of the previous study demonstrated that it is possible to mill cement to approximately 20 to 25 mu m and use it to seal fracture aperture down to approximately 70 mu m. Further milling deteriorates the penetrability of the grouts due to the flocculation of the fine particles. This study investigates ultrasound as a technique to improve dispersion of grouts based on ultrafine milled cement. The grout tested is based on cement where 95% of the cement mass has particles smaller than 12 mu m and is very hard to disperse. Dispersion with ultrasound is compared with a conventional laboratory mixer equipped with a disk and rotor-stator system. The dispersion efficiency of this mixing equipment was tested by a filter pump. The results confirmed that a conventional laboratory mixer equipped with a disk is not at all suitable for dispersion of this grout. The laboratory mixer equipped with a rotor-stator system is much better than a disc but still cannot disperse this fine milled grout properly. Ultrasound was found to be the most effective method. The dispersion achieved, measured with a filter pump, was around 54 mu m which indicates that it is possible to seal fracture aperture now down to 54 mu m, which is a significant improvement., QC 20220121

This master thesis has investigated the performance of a deep excavation with a jet grout bottom plug used to prevent bottom heave and hydraulic uplift failure. The concept of a jet grout plug as a structural and sealing component in a specific case was studied, namely one of the tunnel sections of The West Link tunnel project in Gothenburg. The section was to be built as a cut-and-cover tunnel with the excavation shaft consisting of secant pile walls, struts and a jet grout bottom plug. It is to be established where there are a lot of sensitive buildings and constructions close to the excavation site. This makes it important not to disturb the surroundings during construction with, for example, settlements.The study was carried out by doing a literature study, analytical calculations and numerical simulations in the finite element software PLAXIS 2D. More specifically, the checks evaluated were uplift equilibrium of the jet grout plug and of the whole structure, structural performance of the jet grouted plug and hydraulic conductivity of the jet grouted mass.The results show a design of a jet grout plug that together with the additional structures works sufficiently enough to make a secure construction for a deep excavation below the ground water table. The structural performance of the jet grouted plug to function as a strut level is fulfilled even if the jet grout is not perfectly performed. To work as a sealing component the jet grout column pattern and the centre-to-centre distance between the columns are important factors together with the alignment and diameter of the jet grout columns. To make a completely watertight construction is however almost impossible in this case since the jet grout plug is located at a large depth (around 20 m). To work properly against failure by uplift it does not need to be completely watertight. Instead, the use of relief wells makes sure that the pore water pressure is not larger than the vertical stress from the soil, otherwis

Due to an increasing amount of aging tendencies in Swedish embankment dams, failures such as internal erosion has become a more common problem. Internal erosion is a phenomenon where certain soil material within the embankment dam is removed, often over a longer period of time. It is most common to occur at the inner core of the dam, and if it is allowed to continue for a longer time period the consequences can be disastrous. During the internal erosion, the inner material is washed out, creating larger voids and lowering the geotechnical stability of the dam. When larger voids start to appear, the seepage will increase allowing more material to be washed out and accelerating the process. In order to repair an embankment dam, exposed to inner erosion, it requires both the location of the faults as well as a suitable method of repairing. A method to repair internal erosion is by using grout and injecting it into the location of the fault. The knowledge regarding what type of grout and how it should be treated is today lacking. There are reasons to believe that a hardening mixture within an embankment dam using a till core will not cooperate well. For that reason, a grout with non-hardening properties is of interest. this thesis focuses on the Geomechanical strength parameters of two similar experimental non-hardening grouts. One with maximum grain size of 2 mm referred as grout 0/2, and one with maximum grain size of 4 mm, referred to as grout 0/4. The grouts consist of natural aggregates, calcium carbonate, water, bentonite, superplasticizer and defoamer. The grouts are evaluated by its undrained shear strength, water content, bulk- and dry density using fall cone tests and uniaxial compressive strength tests. To evaluate the grouts angle of friction and angle of dilatancy together with young’s modulus, consolidated, drained triaxial tests were performed. Three tests with different consolidation pressures (50, 150 and 300 kPa) were performed for each grout. Sinc, På grund av en ökad mängd med föråldrandetendenser hos svenska jordfyllningsdammar har brott så som inre erosion blivit ett alltmer vanligt problem. Inre erosion är ett fenomen där en viss jord inom jordfyllningsdammen är avlägsnad, generellt över en längre tidsperiod. Oftast inträffar detta vid den inre damkärnan och om erosionen är tillåten att fortskrida sig över en längre period kan konsekvenserna bli förödande. Inre erosion fungerar så att jordmaterial tvättas ut vilket skapar hålutrymmen och minskar den geotekniska hållfastheten för dammen. När större hålutrymmen bildats ökar läckaget som i sin tur tillåter mer material att bli urtvättat och processen blir accelererad. För att kunna reparera en jordfyllningsdam, utsatt för inre erosion, krävs både att platsen för brottet och metoden för att reparera är kända. En metod för att reparera inre erosion är genom att använda injektering och injektera hålutrymmet. Dock är kunskapen gällande vad för typ av injektering och hur den ska hanteras icke existerande i dagsläget. Det finns anledning att tro att ett härdande bruk inom en jordfyllningsdam, med en moränkärna, inte kommer samarbeta särskilt bra. På grund av det har ett bruk med icke-härdande egenskaper undersökt. Den här uppsatsen fokuserar på de geotekniska hållfasthetsegenskaperna för två liknande experimentella icke-härdande bruk. Ett med maximal kornstorlek på 2 mm benämnd som bruk 0/2 och ett med maximal kornstorlek på 4 mm, benämnd som bruk 0/4. Bruket består av natursand, kalciumkarbonat, vatten, bentonit, mjukgöringsmedel och skumdämpare. Bruken är utvärderade genom deras odränerade skjuvhållfasthet, vattenkvot, skrym- och torrdensiteten som har tagits fram från fallkorns-test och enaxiella trycktest (UCS). För att utvärdera brukens friktionsvinkel och dilationsvinkel tillsammans med styvheten (initiella och 50 %) har konsoliderat, dränerat triaxiala tests utförts. Tre test med varierande konsolideringstryck (50, 150 och 300 kPa) har utförts för båda bruk

The liquid distribution of unsaturated wet granular media composed of granular materials and Newtonian fluid has been in detail studied. However, when a granular material is mixed with a certain amount of Bingham fluid, the effect of rheological properties of Bingham fluid on the deposition morphologies is not clearly explored. In this study, the adhesion rules of fresh cement grout flowing through granular materials without considering the filtration effect is investigated, and the deposition morphologies of cement grout in random packing of spheres is observed with the help of X-ray microtomography device. The results show that the deposition mechanism of cement grout is significantly dependent on its yield stress. The cement grout spontaneously forms open structures with large liquid–air interface. The morphologies of cement grout within cemented granular materials vary with grout content. With the increase of the yield stress of cement grout, neighbouring smaller clusters gradually touch each other and coalesce into more complex structure, and the largest cluster can contain almost all the cement grout.

The soil-grout interface friction was measured to be in between 0.0 [kPa] and 14 [kPa]. To measure this friction, a special research method was invented that enabled a tunnel to be recreated. With this setup, any formation could be used. The formation could be created with a hole in the middle which simulated a borehole. Next, by filling and pressurising this hole with a bentonite-water suspension, a stable borehole could be simulated. This borehole was then filled with drillgrout to recreate a tunnel filled with grout. This grout column could then be pulled out of the soil formation so that the friction between the drillgrout and soil could be measured. In this setup, no normal forces were present. Due to the absence of normal forces no friction angle could be deducted which made it impossible to estimate the effect of the friction at the depth where a pipe laid by HDD would generally be found. It was concluded that based on the data found, it is not recommended to use grout as a borehole filling around heat transportation pipes. Although the friction would be mainly determined by the filter cake strength, which is comparable to a weak clay, effects like irregular borehole diameters and large soil stresses at the depth of the pipe, would create a frictional force that is large enough to cause buckling or failure of the insulating PUR layer., Applied Earth Sciences

Tunneldrivning är tidskrävande med varierande komplexitet från projekt till projekt, där en betydande del av sprängcykeln innefattar att låta injektering härda. Detta är tid där tunneldrivandet står stilla. Ifall denna tid skulle kunna reduceras skulle entreprenörer kunna spara in resurser genom att kunna spränga tidigare. Huvudsyftet med det här examensarbetet är att bidra med förståelse för hur utomstående krafter påverkar injektering. Detta för att man på ett korrekt sätt ska kunna dimensionera och reducera injekteringens härdningstid vid en tunneldrivning. Innan examensarbetets start hade tre olika kravställningar för cementbaserad injektering tagits fram. En del av examensarbetet inkluderade att formulera injekteringsrecept uppfyllande dessa krav, genom att få ökad förståelse för cementbruks reologi. Genomförandet av arbetet delades upp i tre studier, där cementbruks reologi studerades på olika sätt. Arbetet började med att se hur viskositet och flytgräns ändrades med vattencementtal (VCT) med hjälp av en rheometer (roterande tester). Dessa undersökningar utgjorde studie 1. De vattencementtal som testades var 0,6; 0,8; 1,0 och 1,2. Från denna studie blev värdena höga och ansågs orimliga. Då cement är ett av de reologiskt mest komplicerade materialen rör det sig över stora delar av det viskoelastiska spektret. Det kunde konstateras att vidare studier bör utföras för att öka förståelsen för dels rheometern som mätredskap, dels cementets reologi. I studie 2 mättes samma parametrar som i den första studien, samt inträngningsförmåga, separation och densitet. Dessa tester genomfördes med hjälp av redskapen PenetraCone, Mud Balance, Marshkon, fallkon, muggprover och Yield Stick i laboratoriemiljö. Testerna genomfördes med samma vattencementtal som tidigare, men med två olika sorters cement: Injektering-30 och UltraFine 20. Från dessa tester kunde det konstateras att två av tre krav inte gick att uppfylla med UltraFine 20. Injektering-30 uppfyllde två av kraven med et, Tunnel excavation is time demanding with varying complexity. A significant part of the tunnel excavation cycle consists of letting grout harden. This is time where the excavation basically is put on hold. If this part of the excavation cycle could be reduced, the contractor would be able to save resources by conducting blasting earlier. The main purpose with this master thesis is to contribute with knowledge regarding how external forces affects grout. This is of significance to be able to design and to reduce the grout’s hardening time correctly. Before this master’s thesis began three different requirements for cement grout had been developed. One part of this master’s thesis included formulating grout recipes to fulfill these requirements, by gaining further knowledge regarding cement grout rheology. The execution of this work was divided into three part-studies where cement rheology was studied in different ways. The work started by investigating the water cement ratios influence on cements viscosity and yield point by performing rotating tests with a rheometer. This investigation was a part of study 1. The water cement ratios which were studied was 0.6, 0.8, 1.0 and 1.2. It was concluded that the results were way to high and was deemed unreasonable. Cement is rheologically one of the most complex materials, because it spans over great parts of the viscoelastic spectrum. It was concluded that further studies should be performed to further understand both how the rheometer works and cements rheology. In study 2, the same parameters were measured as in the previous study with the addition of penetrability, separation, and density. These tests were performed with PenetraCone, Mud Balance, Marsh funnel, fall cone, mug tests and Yield Stick tests in a laboratory environment. The tests were conducted with the same water cement ratios as in study 1, but with two different brands of cement: Injektering-30 and UltraFine 20. From these tests the conclusion was that it wa

The grouting in water-rich fractured rock masses is a process in which the pressurized grouts gradually displace the existing water. It is important to thoroughly investigate the grout-water displacement laws for improving the engineering grouting efficiency. In this study, a visualization technique that incorporates the particle image velocimetry (PIV) into the grout-water displacement tests is established, and is used to capture the flow field distribution in a 3D-printed transparent rough-walled fracture along with the flow velocity and hydraulic pressure measurements. The Navier-Stokes equations are solved based on the finite element method to simulate the displacement process, and the simulation is compared with the experimental observations. The results show that under the constant flow rate, the injection pressure first increases gently, followed by a rapid increase stage, and finally approaches a constant value. The grouts preferentially flow through some major channels, and the injection pressure tends to increase gently after the grout reaches the outlet. The residual water is mainly distributed in the dead end close to the edge of main flow channels and the locations where sudden changes in aperture happen. The parallel-plate model can underestimate the injection pressure by up to 45% comparing to the corresponding rough-walled model. It is therefore necessary to consider fracture roughness in the theoretical assessment of grouting pressures to achieve better grouting performance., QC 20230602

Tunneldrivning är tidskrävande med varierande komplexitet från projekt till projekt, där en betydande del av sprängcykeln innefattar att låta injektering härda. Detta är tid där tunneldrivandet står stilla. Ifall denna tid skulle kunna reduceras skulle entreprenörer kunna spara in resurser genom att kunna spränga tidigare. Huvudsyftet med det här examensarbetet är att bidra med förståelse för hur utomstående krafter påverkar injektering. Detta för att man på ett korrekt sätt ska kunna dimensionera och reducera injekteringens härdningstid vid en tunneldrivning. Innan examensarbetets start hade tre olika kravställningar för cementbaserad injektering tagits fram. En del av examensarbetet inkluderade att formulera injekteringsrecept uppfyllande dessa krav, genom att få ökad förståelse för cementbruks reologi. Genomförandet av arbetet delades upp i tre studier, där cementbruks reologi studerades på olika sätt. Arbetet började med att se hur viskositet och flytgräns ändrades med vattencementtal (VCT) med hjälp av en rheometer (roterande tester). Dessa undersökningar utgjorde studie 1. De vattencementtal som testades var 0,6; 0,8; 1,0 och 1,2. Från denna studie blev värdena höga och ansågs orimliga. Då cement är ett av de reologiskt mest komplicerade materialen rör det sig över stora delar av det viskoelastiska spektret. Det kunde konstateras att vidare studier bör utföras för att öka förståelsen för dels rheometern som mätredskap, dels cementets reologi. I studie 2 mättes samma parametrar som i den första studien, samt inträngningsförmåga, separation och densitet. Dessa tester genomfördes med hjälp av redskapen PenetraCone, Mud Balance, Marshkon, fallkon, muggprover och Yield Stick i laboratoriemiljö. Testerna genomfördes med samma vattencementtal som tidigare, men med två olika sorters cement: Injektering-30 och UltraFine 20. Från dessa tester kunde det konstateras att två av tre krav inte gick att uppfylla med UltraFine 20. Injektering-30 uppfyllde två av kraven med et, Tunnel excavation is time demanding with varying complexity. A significant part of the tunnel excavation cycle consists of letting grout harden. This is time where the excavation basically is put on hold. If this part of the excavation cycle could be reduced, the contractor would be able to save resources by conducting blasting earlier. The main purpose with this master thesis is to contribute with knowledge regarding how external forces affects grout. This is of significance to be able to design and to reduce the grout’s hardening time correctly. Before this master’s thesis began three different requirements for cement grout had been developed. One part of this master’s thesis included formulating grout recipes to fulfill these requirements, by gaining further knowledge regarding cement grout rheology. The execution of this work was divided into three part-studies where cement rheology was studied in different ways. The work started by investigating the water cement ratios influence on cements viscosity and yield point by performing rotating tests with a rheometer. This investigation was a part of study 1. The water cement ratios which were studied was 0.6, 0.8, 1.0 and 1.2. It was concluded that the results were way to high and was deemed unreasonable. Cement is rheologically one of the most complex materials, because it spans over great parts of the viscoelastic spectrum. It was concluded that further studies should be performed to further understand both how the rheometer works and cements rheology. In study 2, the same parameters were measured as in the previous study with the addition of penetrability, separation, and density. These tests were performed with PenetraCone, Mud Balance, Marsh funnel, fall cone, mug tests and Yield Stick tests in a laboratory environment. The tests were conducted with the same water cement ratios as in study 1, but with two different brands of cement: Injektering-30 and UltraFine 20. From these tests the conclusion was that it wa

Self Healing Concrete SHC is a bacterium that is able to change organic nutrients so that calcium deposition occurs when cracked and tightly closes cracks in concrete, the way bacteria work as self-healing agents for concrete in concrete can occur if the concrete is damaged in the form of cracks or cracks, slowly The encapsulation of the bacteria will fill the crack by growing endospores which are stimulated or assisted by oxygen O2 and water H2O. It's just that the ability of self-repair of concrete by utilizing this bacterial encapsulation can only cover the cracks experienced by concrete in the range of 3-5 mm. Self-healing concrete uses microbial capabilities for the purpose of deposition of CaCO3 (calcium carbonate). This research was conducted at the Laboratory of Civil Engineering Study Program, Faculty of Engineering, Islamic University of Riau. The author conducts material inspection, mix design, manufacture of test objects (cubes), concrete treatment and compressive strength testing. The concrete specimens were 27 samples where 3 were normal concrete, 12 concrete with cracks and 12 concrete without cracks, with a concrete mold size of 15cm x 15cm x 15cm, the first mixing with normal concrete without vege grout, the second mixing with a variation of 3%, 5% , 7%, 9% totaling 12 samples replaced the weight of cement to be tested using a concrete compressive strength machine at 28 days of treatment. the third mixing with variations of 3%, 5%, 7%, 9% totaling 12 samples replacing the weight of cement to be cracked using a hammer after 28 days of treatment, after that the cracked sample was recovered for 28 days, then the sample was tested for pressure, for immersion using sea water. The value of the compressive strength of concrete at 28 days of treatment using sea water bath and a mixture of 0% vege grout variation is 31,690 Mpa, 3% mix variation is 42,851 Mpa, 5% mix variation is 34.514 Mpa, 7% mix variation is 34.261 Mpa, and mixed variation 9% is 30.819 MPa

Self-healing concrete or SHC is a concrete that can independently repair cracks in concrete and is expected to fill the pores in concrete with the production of CaCO3 minerals caused by the activity of microorganisms in the concrete, these microorganisms are produced from the extraction process carried out on vegetable waste grout) what if this vegetable waste extract (vege grout) is mixed with urea and CaCl to produce calcium carbonate CaCO3. There are 27 samples of concrete test objects, where the size of the concrete mold is 15cm x 15cm x 15cm totaling 3 specimens for each variation. 0% totaling 3 samples, the first stirring with variations of 3%, 5%, 7%, 9% totaling 12 samples to replace the weight of cement to be tested using a concrete compressive strength machine at 28 days of treatment. second mixing with variations of 3%, 5%, 7%, 9% totaling 12 samples replacing the weight of cement to be cracked using a hammer after 28 days of treatment, after that the cracked sample was recovered for 28 days, then the sample was tested for pressure, for immersion using peat water. The value of the compressive strength of concrete at 28 days of treatment using peat water bath and 0% variation of vege grout was 31,690 Mpa, 3% mixed variation was 42,851 Mpa, 5% mixed variation was 34.514 Mpa, 7% mixed variation was 34.261 Mpa, and mixed variation 9% is 30.819 MPa, where the mixture variation of 3% gets the highest compressive strength value. For concrete after cracking, it remains the same, where the highest number is found in concrete with a mixture variation of 3%, which is 33,227 Mpa and decreases with variations of 5%, 7%, 9% with values of 26.207 Mpa, 25,786 Mpa, and 25,280 Mpa, respectively. After visually looking at the cracks in the concrete, the changes that occur are not so significant, only calcification occurs on the surface of the concrete but the cracks in the concrete cannot recover as expected, only crack types less than 1mm can be recovered.

The soil-grout interface friction was measured to be in between 0.0 [kPa] and 14 [kPa]. To measure this friction, a special research method was invented that enabled a tunnel to be recreated. With this setup, any formation could be used. The formation could be created with a hole in the middle which simulated a borehole. Next, by filling and pressurising this hole with a bentonite-water suspension, a stable borehole could be simulated. This borehole was then filled with drillgrout to recreate a tunnel filled with grout. This grout column could then be pulled out of the soil formation so that the friction between the drillgrout and soil could be measured. In this setup, no normal forces were present. Due to the absence of normal forces no friction angle could be deducted which made it impossible to estimate the effect of the friction at the depth where a pipe laid by HDD would generally be found. It was concluded that based on the data found, it is not recommended to use grout as a borehole filling around heat transportation pipes. Although the friction would be mainly determined by the filter cake strength, which is comparable to a weak clay, effects like irregular borehole diameters and large soil stresses at the depth of the pipe, would create a frictional force that is large enough to cause buckling or failure of the insulating PUR layer., Applied Earth Sciences

The use of construction and demolition waste is an effective solution to mitigate their environmental impacts and avoid dispose in landfills. This paper aims to evaluate the use of fine recycled-concrete aggregate (FRCA) in grout mixtures used in soil nailing. Compressive strength tests on FRCA grout were carried out at different curing ages and interface shear strength was measured between soil and grout. Properties of a commonly used cement grout are compared with those of sand-cement grout and FRCA-cement grout. Although the FRCA grout shows a lower compressive strength compared to commonly used grout and sand-cement grout, its measured properties still meet the minimum standards requirements. The interface friction angle and adhesion of the FRCA exhibit higher values compared to those measured at the soil-soil interface. The grout mixtures evaluated in this study indicated that it is possible to use 1.126 kg of FRCA for each cubic meter of grout. The consumptions of cement and water were found to be 42% and 24% lower, respectively. This represents approximately 380 kg less of CO2 emissions into the atmosphere per cubic meter. The use of FRCA in soil nail grouting can be a sustainable alternative to reduce environmental impacts, cement consumption, and greenhouse gas emission. © 2021 American Society of Civil Engineers.

The use of construction and demolition waste is an effective solution to mitigate their environmental impacts and avoid dispose in landfills. This paper aims to evaluate the use of fine recycled-concrete aggregate (FRCA) in grout mixtures used in soil nailing. Compressive strength tests on FRCA grout were carried out at different curing ages and interface shear strength was measured between soil and grout. Properties of a commonly used cement grout are compared with those of sand-cement grout and FRCA-cement grout. Although the FRCA grout shows a lower compressive strength compared to commonly used grout and sand-cement grout, its measured properties still meet the minimum standards requirements. The interface friction angle and adhesion of the FRCA exhibit higher values compared to those measured at the soil-soil interface. The grout mixtures evaluated in this study indicated that it is possible to use 1.126 kg of FRCA for each cubic meter of grout. The consumptions of cement and water were found to be 42% and 24% lower, respectively. This represents approximately 380 kg less of CO2 emissions into the atmosphere per cubic meter. The use of FRCA in soil nail grouting can be a sustainable alternative to reduce environmental impacts, cement consumption, and greenhouse gas emission. © 2021 American Society of Civil Engineers.

The use of construction and demolition waste is an effective solution to mitigate their environmental impacts and avoid dispose in landfills. This paper aims to evaluate the use of fine recycled-concrete aggregate (FRCA) in grout mixtures used in soil nailing. Compressive strength tests on FRCA grout were carried out at different curing ages and interface shear strength was measured between soil and grout. Properties of a commonly used cement grout are compared with those of sand-cement grout and FRCA-cement grout. Although the FRCA grout shows a lower compressive strength compared to commonly used grout and sand-cement grout, its measured properties still meet the minimum standards requirements. The interface friction angle and adhesion of the FRCA exhibit higher values compared to those measured at the soil-soil interface. The grout mixtures evaluated in this study indicated that it is possible to use 1.126 kg of FRCA for each cubic meter of grout. The consumptions of cement and water were found to be 42% and 24% lower, respectively. This represents approximately 380 kg less of CO2 emissions into the atmosphere per cubic meter. The use of FRCA in soil nail grouting can be a sustainable alternative to reduce environmental impacts, cement consumption, and greenhouse gas emission. © 2021 American Society of Civil Engineers.

Recent research on the mechanical characterisation of Steel Reinforced Grout (SRG) has highlighted its excellent performance as strengthening solutions for masonry structures. Using SRG with limited fabric density ensures a good textile-matrix interlocking, preventing at the same time the failure due to slippage or debonding from the substrate. This paper presents an experimental investigation on the use of SRG as in-plane strengthening solution for shear masonry walls composed of handmade solid clay brick and hydraulic lime mortar. Cyclic shear compression tests were carried out on walls strengthened with SRG comprising low density steel sheets (LDS). The SRG was applied on both faces of the walls with a strip configuration, using one and two layers of LDS. The experimental programme aimed to study the influence of the number of textile layers on the in-plane response of strengthened masonry walls in terms of failure mechanism, load-bearing capacity, energy dissipation, and ductility., The authors gratefully acknowledge the financial support from the Ministry of Economy and Competitiveness, Spain and from the Ministry of Science, Innovation and Universities of the Spanish Government, as well as that of the ERDF (European Regional Development Fund) through the project SEVERUS (Multilevel evaluation of seismic vulnerability and risk mitigation of masonry buildings in resilient historical urban centres, Ref. num. RTI2018-099589-B-I00). The reinforcement systems and construction of the specimens for the experimental programme have been funded by Kerakoll Spa through the RTD project “Seismic Strengthening of Masonry Walls” (Ref. num. A-01278). The authors wish to thank Paolo Casadei, José Luis Sanchez and José Dobón from Kerakoll Spa for their involvement and support. The support from Secretaria d’Universitats i Investigació de la Generalitat de Catalunya, Spain through a predoctoral grant awarded to the first author is also gratefully acknowledged., Peer Reviewed, Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles, Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura::9.1 - Desenvolupar infraestructures fiables, sostenibles, resilients i de qualitat, incloent infraestructures regionals i transfrontereres, per tal de donar suport al desenvolupament econòmic i al benestar humà, amb especial atenció a l’accés assequible i equitatiu per a totes les persones, Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura, Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles::11.4 - Redoblar els esforços per a protegir i salvaguardar el patrimoni cultural i natural del món, Objectius de Desenvolupament Sostenible::13 - Acció per al Clima, Objectius de Desenvolupament Sostenible::13 - Acció per al Clima::13.1 - Enfortir la resiliència i la capacitat d’adaptació als riscos relacionats amb el clima i els desastres naturals a tots els països, Postprint (author's final draft)

During the assembling of a steel structure with anchors, grout should be used in connections be- tween steel elements and a reinforced concrete support element. In horizontal and vertical joints, grout is used as a good construction practice for solving geometric tolerance problems. Grout can be used with cast-in anchors or post-installed anchors. However, the relation between anchor shear resistance and characteristic grout compressive strength is not described in detail in tech- nical regulations. The behaviour of a connection considering achieved slip tolerances should match the boundary conditions set in the global analysis. In the support joint, grout properties could influence the value of the slip between a steel part and a concrete part of the joint. Slip value could be significant for the relevant design cases featuring the interaction of shear force and ten- sion force. In this paper, results of the push-out test conducted on anchors are presented. Based on the experimental test, the finite element analysis was performed to investigate the shear con- nection behaviour. According to the preliminary results, it can be concluded that a grout strength and a grout thickness influence the connection response when serviceability loads are applied, alt- hough they do not influence the ultimate load bearing capacity of anchors. In some cases, using the contemporary solutions of high strength grout materials, the slip between steel and concrete parts in the connection could be reduced.

Prefabricated construction and requirements for reusing the particular structural element, request the application of a support joint realized with anchors. Besides demountability, the connection detail realized with anchors needs to satisfy all support conditions adopted during the structure design. This paper describes the behaviour of anchor shear connection. The connection slip was analysed concerning the grout material properties and the grout thickness. The parametric study was performed using Abaqus software to define the relationship between grout properties and thickness and the slip deformation for load levels corresponding to serviceability limit states.

Grouting has long been implemented as a ground improvement technique to reduce the seepage through the rock mass. Grout curtains are usually constructed under dams as a barrier to prevent leakage from the reservoir. So far, the grout curtains under dams have mainly been designed by using an empirical design approach. However, the empirical approach has its limitations. Generally, the usage of “rules of thumbs” makes the design highly dependent on the experience of the designers. Lack of experience can result in insufficient or over-conservative grout curtains. For example, the stop criteria for the grouting process adopted by the empirical approach can lead to long grouting time and thus becomes inefficient. In addition, high grouting pressure may cause unexpected deformations of the rock and open up new leakage paths. To deal with these limitations, a theory-based design methodology has been developed. Theories on rock grouting developed in recent decades are used to build up the design methodology. In the theory-based design methodology, the grout curtain is treated as a structural component in the dam foundation. The geometry and location of the grout curtain is first designed with respect to three requirements: (i) the hydraulic conductivity reduction, (ii) prevention of erosion of fracture infillings and (iii) optimization of uplift reduction. Grouting work is then designed to obtain the designed geometry of the grout curtain. In the design of the grouting work, analytical calculations are implemented to determine the grouting pressure, grouting time and grout hole layout. The stop criteria are based on the grouting time, which is believed to obtain better efficiency. The principles of the observational method are implemented to deal with the uncertainties involved in the grouting process. One of the main limitations with the proposed methodology is the limited research on the erosion process of fracture infilling materials in flowing water. To study this issu, Injektering har länge använts som en metod för att förstärka grunden och reducera vattenflödet i en bergmassa. Injekteringsridåer uppförs ofta under dammar som en barriär med syfte att förhindra läckage av magasinets vatten. Hittills har injekteringsridåerna i huvudsak dimensionerats baserat på empiriska metoder. De empiriska metoderna har emellertid sina begränsningar. Användandet av olika tumregler resulterar i att dimensioneringen i hög utsträckning är beroende av ingenjörens erfarenhet. Brist på erfarenhet kan resultera i en ineffektiv, eller en för konservativ, utformning av injekteringsridåerna. Till exempel kan de stoppkriterier som tillämpas i det empiriska tillvägagångssättet leda till en för lång injekteringstid och därmed bli ineffektiv. Utöver detta kan höga injekteringstryck leda till oväntade deformationer i bergmassan och nya läckagevägar. För att hantera dessa typer av begränsningar har en teoribaserad dimensioneringsmetodik utvecklats. Teorier för berginjektering som utvecklats under de senaste decennierna används för att bygga upp metodiken. I metodiken utformas injekteringsridån som en strukturell komponent i berggrunden under dammen. Den geometriska utformningen och läget för injekteringsridån bestäms med hänsyn till tre kriterier: (i) erforderlig reduktion av den hydrauliska konduktiviteten, (ii) förhindrande av erosion av sprickfyllnadsmaterial, och (iii) optimering av reduktionen i upptryck under dammen. Injekteringsarbetet utformas därefter i syfte att eftersträva den erforderliga utformningen. I utformningen av injekteringsarbetet används analytiska beräkningar för att bestämma injekteringstryck, injekteringstid och hålavstånd. Stoppkriterier baseras på erforderlig injekteringstid, vilket bedöms uppnå en mer effektiv injektering. Principerna för observationsmetoden används för att hantera de osäkerheter som kvarstår. En av de huvudsakliga begränsningarna med den föreslagna metodiken är den begränsade kunskapen som idag finns om erosion av s, QC 210512

In tunnel engineering one of the most important factors are the groundwater flow. To solve this problem a method called grouting is commonly used. In this study grout mixes are developed based on specific requirements for a deep shaft located next to a body of water. These circumstances require a grout with extraordinary penetrability and durability. During the excavation of a shaft, different groundwater pressures and fracture structures is going to be present. This creates conditions where different types of grouts are necessary. In order to develop grout, there are several factors that needs to be taken into consideration. Some of these are the cement properties, additive properties and amounts, water cement ratio, mixing regime, external physical impact etc. In this study several experiments were used to determine the properties of the grout mixes in order to fulfil the requirements needed for certain rock conditions. Three different cements and several additives have been used in different combinations in order to find the right mix. The first step of the experimental process is to do screening tests. The screening tests consists of penetrability, flow and density tests. After a grout passes these tests, several other tests are performed to ensure the right properties. In the beginning of the experiments, problems occurred with one of the cements which led us to suspect the quality of the cement. In order to ensure that the sources of error from lab equipment, different production dates, conditions of cements and additives are excluded several tests were performed. The test results of the cement did not improve regardless of the troubleshooting.When another cement type was tested the results immediately improved and passed the screening test. The test results from the new cements and additives led to further testing and development of two approved grout mixes. When another cement type was tested the results immediately improved and passed the screening test. Th, Vid tunnelbyggande är en av de största utmaningarna tätning av berget för att undvika vatteninträngning. Detta är viktigt av flera anledningar. Grundvatteninträngning kan resultera i en lokal grundvattensänkning som kan medföra förödande konsekvenser. Det kan leda till sättningar som i sin tur leder till skador på byggnader och även den befintliga växtligheten kan förstöras av en allt för stor grundvattensänkning. Det finns flera tekniska åtgärder till detta problem och ett exempel på detta är tätning med injekteringsbruk.Syftet med denna studie var att utveckla tre olika injekteringsbruk som har de egenskaper som krävs i schaktet vid Stadsgårdskajen. Egenskaperna som hade krav på att uppfyllas var penetrationsförmåga, sättningstid, sträckgräns, skjuvhållfasthet, rinntest, vattenseparation och densitet.Studien är i huvudsak byggd på det egna laborerade arbetet men har kompletterats med vetenskapliga rapporter där den viktigaste källan var Betonghandboken Material. För att få kunskap om de specifika materialen som användes i studien fanns tekniska datablad för respektive produkt.Resultaten visar hur olika cementtyper reagerar med olika kombinationer av tillsatser och vattencementtal. Tester genomfördes på tre olika typer av portlandcement varav två av dessa var sulfatresistenta. Tillsatserna som användes i studien var superplasticerare, accelerator, retarder och viskositetstabiliserare. Resultaten är uppdelade i VCT (vattencementtal) för respektive cementtyp.Några slutsatser av studien är att RHEOCEM 650 SR inte fungerade som förväntat. Detta sannolikt på grund av dålig cementkvalité. MasterRoc MP 650 och Injektering 30 gav betydligt bättre resultat och det är från Injektering 30 som de båda godkända mixarna utvecklades från. Ifall fortsatta studier hade genomförts hade en godkänd mix 1 utvecklats. Det hade även varit intressant att se hur de olika godkända mixarna fungerade i praktiken.

To reduce the water leakage and the uplift pore pressure in the rock foundation, grout curtains are oftenconstructed under dams. However, the design of grout curtains has long been based on empirical knowledge.When designing the grout curtain, focus was mainly given on closing the curtain and limiting the leakage,without considering the thickness of the curtain. However, a too thin grout curtain could lead to high gradients,which with time could result in internal erosion of degraded grout and fracture infilling materials. This couldlead to poor performance and durability problems, potentially jeopardizing the dam safety and increasingthe cost for remedial measures. In this paper, three design criteria are discussed for determining the requiredthickness of the grout curtain, including water loss reduction, uplift pore pressure reduction and internalerosion of degraded grout and fracture infilling materials. Analyses on the required thickness are made fora typical concrete gravity dam. The results show that the required thickness is significantly affected by theinternal erosion of fracture infilling materials. These results show the need for a more refined design approachfor the grout curtains based on the suggested criteria., QC 20210527

Determining optimum pressure in a grouting procedure affects a project?s outcome as well as associated costs. Application of relatively low pressure may lead to insufficient grout spread around the borehole and prolongation of grouting time. On the other hand, a pressure higher than in-situ stresses can lead to jacking of the fractures and consequently increase of usage of grout, and in much higher pressures, ground heaving and uplifts. In a review of current practices, the ?apparent lugeon? method uses low pressure regardless of geology and function of the grouted zone. The theoretical approach of RTGC estimates the grout spread from grouting borehole in a fracture with constant size aperture, which obligates the usage of a pressure that avoids any deformations. On the other hand, the GIN method appreciates the usage of higher grouting pressures while the induced energy is controlled. However, the controlling Grout Intensity Number is determined based on experience and provides no information regarding the distance that grout mix is spreading and the state of fracture during grouting. The present study discusses an analytical approach that defines stop criteria that allow the spread of grout to a certain distance while controlling deformations to the extent that ensures fracture jacking remains beneficial. To elaborate this approach, first the concept of fracture jacking and approaches for detecting onset and duration of it are reviewed. This is followed by a discussion of the positive and negative effects of fracture jacking and the determination of thresholds for limiting these deformations. The paper goes on to explain the analytical solution for establishing the Deformation Limiting Curves as a stop criterion and estimation of the grout spread distance in a continuously dilating fracture. The significance and benefits of this solution are argued through case studies involving different functions and geological conditions. It is concluded that understanding the, QC 20210524

To reduce the water leakage and the uplift pore pressure in the rock foundation, grout curtains are oftenconstructed under dams. However, the design of grout curtains has long been based on empirical knowledge.When designing the grout curtain, focus was mainly given on closing the curtain and limiting the leakage,without considering the thickness of the curtain. However, a too thin grout curtain could lead to high gradients,which with time could result in internal erosion of degraded grout and fracture infilling materials. This couldlead to poor performance and durability problems, potentially jeopardizing the dam safety and increasingthe cost for remedial measures. In this paper, three design criteria are discussed for determining the requiredthickness of the grout curtain, including water loss reduction, uplift pore pressure reduction and internalerosion of degraded grout and fracture infilling materials. Analyses on the required thickness are made fora typical concrete gravity dam. The results show that the required thickness is significantly affected by theinternal erosion of fracture infilling materials. These results show the need for a more refined design approachfor the grout curtains based on the suggested criteria., QC 20210527

Grouting has long been implemented as a ground improvement technique to reduce the seepage through the rock mass. Grout curtains are usually constructed under dams as a barrier to prevent leakage from the reservoir. So far, the grout curtains under dams have mainly been designed by using an empirical design approach. However, the empirical approach has its limitations. Generally, the usage of “rules of thumbs” makes the design highly dependent on the experience of the designers. Lack of experience can result in insufficient or over-conservative grout curtains. For example, the stop criteria for the grouting process adopted by the empirical approach can lead to long grouting time and thus becomes inefficient. In addition, high grouting pressure may cause unexpected deformations of the rock and open up new leakage paths. To deal with these limitations, a theory-based design methodology has been developed. Theories on rock grouting developed in recent decades are used to build up the design methodology. In the theory-based design methodology, the grout curtain is treated as a structural component in the dam foundation. The geometry and location of the grout curtain is first designed with respect to three requirements: (i) the hydraulic conductivity reduction, (ii) prevention of erosion of fracture infillings and (iii) optimization of uplift reduction. Grouting work is then designed to obtain the designed geometry of the grout curtain. In the design of the grouting work, analytical calculations are implemented to determine the grouting pressure, grouting time and grout hole layout. The stop criteria are based on the grouting time, which is believed to obtain better efficiency. The principles of the observational method are implemented to deal with the uncertainties involved in the grouting process. One of the main limitations with the proposed methodology is the limited research on the erosion process of fracture infilling materials in flowing water. To study this issu, Injektering har länge använts som en metod för att förstärka grunden och reducera vattenflödet i en bergmassa. Injekteringsridåer uppförs ofta under dammar som en barriär med syfte att förhindra läckage av magasinets vatten. Hittills har injekteringsridåerna i huvudsak dimensionerats baserat på empiriska metoder. De empiriska metoderna har emellertid sina begränsningar. Användandet av olika tumregler resulterar i att dimensioneringen i hög utsträckning är beroende av ingenjörens erfarenhet. Brist på erfarenhet kan resultera i en ineffektiv, eller en för konservativ, utformning av injekteringsridåerna. Till exempel kan de stoppkriterier som tillämpas i det empiriska tillvägagångssättet leda till en för lång injekteringstid och därmed bli ineffektiv. Utöver detta kan höga injekteringstryck leda till oväntade deformationer i bergmassan och nya läckagevägar. För att hantera dessa typer av begränsningar har en teoribaserad dimensioneringsmetodik utvecklats. Teorier för berginjektering som utvecklats under de senaste decennierna används för att bygga upp metodiken. I metodiken utformas injekteringsridån som en strukturell komponent i berggrunden under dammen. Den geometriska utformningen och läget för injekteringsridån bestäms med hänsyn till tre kriterier: (i) erforderlig reduktion av den hydrauliska konduktiviteten, (ii) förhindrande av erosion av sprickfyllnadsmaterial, och (iii) optimering av reduktionen i upptryck under dammen. Injekteringsarbetet utformas därefter i syfte att eftersträva den erforderliga utformningen. I utformningen av injekteringsarbetet används analytiska beräkningar för att bestämma injekteringstryck, injekteringstid och hålavstånd. Stoppkriterier baseras på erforderlig injekteringstid, vilket bedöms uppnå en mer effektiv injektering. Principerna för observationsmetoden används för att hantera de osäkerheter som kvarstår. En av de huvudsakliga begränsningarna med den föreslagna metodiken är den begränsade kunskapen som idag finns om erosion av s, QC 210512

In tunnel engineering one of the most important factors are the groundwater flow. To solve this problem a method called grouting is commonly used. In this study grout mixes are developed based on specific requirements for a deep shaft located next to a body of water. These circumstances require a grout with extraordinary penetrability and durability. During the excavation of a shaft, different groundwater pressures and fracture structures is going to be present. This creates conditions where different types of grouts are necessary. In order to develop grout, there are several factors that needs to be taken into consideration. Some of these are the cement properties, additive properties and amounts, water cement ratio, mixing regime, external physical impact etc. In this study several experiments were used to determine the properties of the grout mixes in order to fulfil the requirements needed for certain rock conditions. Three different cements and several additives have been used in different combinations in order to find the right mix. The first step of the experimental process is to do screening tests. The screening tests consists of penetrability, flow and density tests. After a grout passes these tests, several other tests are performed to ensure the right properties. In the beginning of the experiments, problems occurred with one of the cements which led us to suspect the quality of the cement. In order to ensure that the sources of error from lab equipment, different production dates, conditions of cements and additives are excluded several tests were performed. The test results of the cement did not improve regardless of the troubleshooting.When another cement type was tested the results immediately improved and passed the screening test. The test results from the new cements and additives led to further testing and development of two approved grout mixes. When another cement type was tested the results immediately improved and passed the screening test. Th, Vid tunnelbyggande är en av de största utmaningarna tätning av berget för att undvika vatteninträngning. Detta är viktigt av flera anledningar. Grundvatteninträngning kan resultera i en lokal grundvattensänkning som kan medföra förödande konsekvenser. Det kan leda till sättningar som i sin tur leder till skador på byggnader och även den befintliga växtligheten kan förstöras av en allt för stor grundvattensänkning. Det finns flera tekniska åtgärder till detta problem och ett exempel på detta är tätning med injekteringsbruk.Syftet med denna studie var att utveckla tre olika injekteringsbruk som har de egenskaper som krävs i schaktet vid Stadsgårdskajen. Egenskaperna som hade krav på att uppfyllas var penetrationsförmåga, sättningstid, sträckgräns, skjuvhållfasthet, rinntest, vattenseparation och densitet.Studien är i huvudsak byggd på det egna laborerade arbetet men har kompletterats med vetenskapliga rapporter där den viktigaste källan var Betonghandboken Material. För att få kunskap om de specifika materialen som användes i studien fanns tekniska datablad för respektive produkt.Resultaten visar hur olika cementtyper reagerar med olika kombinationer av tillsatser och vattencementtal. Tester genomfördes på tre olika typer av portlandcement varav två av dessa var sulfatresistenta. Tillsatserna som användes i studien var superplasticerare, accelerator, retarder och viskositetstabiliserare. Resultaten är uppdelade i VCT (vattencementtal) för respektive cementtyp.Några slutsatser av studien är att RHEOCEM 650 SR inte fungerade som förväntat. Detta sannolikt på grund av dålig cementkvalité. MasterRoc MP 650 och Injektering 30 gav betydligt bättre resultat och det är från Injektering 30 som de båda godkända mixarna utvecklades från. Ifall fortsatta studier hade genomförts hade en godkänd mix 1 utvecklats. Det hade även varit intressant att se hur de olika godkända mixarna fungerade i praktiken.

During the assembling of a steel structure with anchors, grout should be used in connections be- tween steel elements and a reinforced concrete support element. In horizontal and vertical joints, grout is used as a good construction practice for solving geometric tolerance problems. Grout can be used with cast-in anchors or post-installed anchors. However, the relation between anchor shear resistance and characteristic grout compressive strength is not described in detail in tech- nical regulations. The behaviour of a connection considering achieved slip tolerances should match the boundary conditions set in the global analysis. In the support joint, grout properties could influence the value of the slip between a steel part and a concrete part of the joint. Slip value could be significant for the relevant design cases featuring the interaction of shear force and ten- sion force. In this paper, results of the push-out test conducted on anchors are presented. Based on the experimental test, the finite element analysis was performed to investigate the shear con- nection behaviour. According to the preliminary results, it can be concluded that a grout strength and a grout thickness influence the connection response when serviceability loads are applied, alt- hough they do not influence the ultimate load bearing capacity of anchors. In some cases, using the contemporary solutions of high strength grout materials, the slip between steel and concrete parts in the connection could be reduced.

Prefabricated construction and requirements for reusing the particular structural element, request the application of a support joint realized with anchors. Besides demountability, the connection detail realized with anchors needs to satisfy all support conditions adopted during the structure design. This paper describes the behaviour of anchor shear connection. The connection slip was analysed concerning the grout material properties and the grout thickness. The parametric study was performed using Abaqus software to define the relationship between grout properties and thickness and the slip deformation for load levels corresponding to serviceability limit states.

To reduce the water leakage and the uplift pore pressure in the rock foundation, grout curtains are oftenconstructed under dams. However, the design of grout curtains has long been based on empirical knowledge.When designing the grout curtain, focus was mainly given on closing the curtain and limiting the leakage,without considering the thickness of the curtain. However, a too thin grout curtain could lead to high gradients,which with time could result in internal erosion of degraded grout and fracture infilling materials. This couldlead to poor performance and durability problems, potentially jeopardizing the dam safety and increasingthe cost for remedial measures. In this paper, three design criteria are discussed for determining the requiredthickness of the grout curtain, including water loss reduction, uplift pore pressure reduction and internalerosion of degraded grout and fracture infilling materials. Analyses on the required thickness are made fora typical concrete gravity dam. The results show that the required thickness is significantly affected by theinternal erosion of fracture infilling materials. These results show the need for a more refined design approachfor the grout curtains based on the suggested criteria., QC 20210527

Grouting has long been implemented as a ground improvement technique to reduce the seepage through the rock mass. Grout curtains are usually constructed under dams as a barrier to prevent leakage from the reservoir. So far, the grout curtains under dams have mainly been designed by using an empirical design approach. However, the empirical approach has its limitations. Generally, the usage of “rules of thumbs” makes the design highly dependent on the experience of the designers. Lack of experience can result in insufficient or over-conservative grout curtains. For example, the stop criteria for the grouting process adopted by the empirical approach can lead to long grouting time and thus becomes inefficient. In addition, high grouting pressure may cause unexpected deformations of the rock and open up new leakage paths. To deal with these limitations, a theory-based design methodology has been developed. Theories on rock grouting developed in recent decades are used to build up the design methodology. In the theory-based design methodology, the grout curtain is treated as a structural component in the dam foundation. The geometry and location of the grout curtain is first designed with respect to three requirements: (i) the hydraulic conductivity reduction, (ii) prevention of erosion of fracture infillings and (iii) optimization of uplift reduction. Grouting work is then designed to obtain the designed geometry of the grout curtain. In the design of the grouting work, analytical calculations are implemented to determine the grouting pressure, grouting time and grout hole layout. The stop criteria are based on the grouting time, which is believed to obtain better efficiency. The principles of the observational method are implemented to deal with the uncertainties involved in the grouting process. One of the main limitations with the proposed methodology is the limited research on the erosion process of fracture infilling materials in flowing water. To study this issu, Injektering har länge använts som en metod för att förstärka grunden och reducera vattenflödet i en bergmassa. Injekteringsridåer uppförs ofta under dammar som en barriär med syfte att förhindra läckage av magasinets vatten. Hittills har injekteringsridåerna i huvudsak dimensionerats baserat på empiriska metoder. De empiriska metoderna har emellertid sina begränsningar. Användandet av olika tumregler resulterar i att dimensioneringen i hög utsträckning är beroende av ingenjörens erfarenhet. Brist på erfarenhet kan resultera i en ineffektiv, eller en för konservativ, utformning av injekteringsridåerna. Till exempel kan de stoppkriterier som tillämpas i det empiriska tillvägagångssättet leda till en för lång injekteringstid och därmed bli ineffektiv. Utöver detta kan höga injekteringstryck leda till oväntade deformationer i bergmassan och nya läckagevägar. För att hantera dessa typer av begränsningar har en teoribaserad dimensioneringsmetodik utvecklats. Teorier för berginjektering som utvecklats under de senaste decennierna används för att bygga upp metodiken. I metodiken utformas injekteringsridån som en strukturell komponent i berggrunden under dammen. Den geometriska utformningen och läget för injekteringsridån bestäms med hänsyn till tre kriterier: (i) erforderlig reduktion av den hydrauliska konduktiviteten, (ii) förhindrande av erosion av sprickfyllnadsmaterial, och (iii) optimering av reduktionen i upptryck under dammen. Injekteringsarbetet utformas därefter i syfte att eftersträva den erforderliga utformningen. I utformningen av injekteringsarbetet används analytiska beräkningar för att bestämma injekteringstryck, injekteringstid och hålavstånd. Stoppkriterier baseras på erforderlig injekteringstid, vilket bedöms uppnå en mer effektiv injektering. Principerna för observationsmetoden används för att hantera de osäkerheter som kvarstår. En av de huvudsakliga begränsningarna med den föreslagna metodiken är den begränsade kunskapen som idag finns om erosion av s, QC 210512