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The wear of cutting tools in mechanised tunnelling is closely linked to the abrasiveness of the present subsoil. Therefore, most of the models used for wear prediction take an abrasiveness index into account. The most common index used for hard rock is the Cerchar Abrasiveness Index (CAI); whereas such a standard does not yet exist for soil. Both the literature research and the results of calculation examples presented in the article show that significantly more practical models are currently available for wear prediction in hard rock. One reason for this is that far more wear‐relevant influencing factors have to be quantified for soft ground. Another reason is that the scientific studies concerning this topic only started in the course of mechanised tunnelling. Since especially the calculations carried out for low‐abrasive rocks differ widely among the different models for tool life, further research is needed also for wear prediction in hard rock [ABSTRACT FROM AUTHOR]

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Map Kabao Tunnel is a significant part of the track doubling project for the railway line connecting Bangkok to Northeast Thailand. The 5.2 km‐long twin‐tube tunnel makes is the longest railway tunnel in Thailand. The conventional tunnelling method was used to excavate the tunnel through complex geological conditions consisting of thrusted and folded carbonate and clastic sedimentary rocks. While encountering a few incidents of tunnelling difficulties caused by the poor quality of the rock mass attributed to weathering, sheared discontinuities, and karst features, the construction of the tunnel was ultimately successful and was completed in 2023. This article provides a comprehensive analysis of the lessons learned from the design and construction of this mountain rail tunnel project. [ABSTRACT FROM AUTHOR]

The Klang Valley Mass Rapid Transit (KVMRT) project involves the construction of an urban passenger transport system, i.e., Mass Rapid Transit (MRT) system, together with the existing urban rail network, will form the backbone of the public transport system in the Greater Kuala Lumpur/Klang Valley region in Malaysia. The first MRT line implemented is the 47 km Kajang Line, of which 9.5 km is underground tunnels with seven underground stations. Construction of the line began on 8 July 2011 and achieved the full line opening on 17 July 2017. The second MRT line―Putrajaya Line―began fully operations on 16 March 2023, stretches from Sungai Buloh to Serdang and ends at Putrajaya for a length of 57.7 km, of which 13.5 km is underground tunnels with 10 new underground stations. Like all other metro underground stations/tunnels designed as part of the urban city, the KVMRT underground construction faces challenges from a technical (engineering design and construction) as well as social (environmental and land related) point of view. Needless to say, underground construction in Klang Valley is intensified with the inherent geotechnical challenges presented by complex ground conditions ranging from hard granite, heterogeneous Kenny Hill formation and extreme karstic limestone with fully developed weathered profiles to soft recent deposits including alluvium and mine tailing that is under‐consolidated in places due to past mining activities. The development of this large‐scale infrastructure project has not only opened up tremendous works and new frontier for tunnelling and geotechnical engineering in Malaysia, but it also provided a wealth of information of unique geotechnical challenges/accomplishments as well as technology breakthrough and design innovation in underground engineering. This article discusses some aspects of geotechnical challenges and interesting lessons learnt as well as numerous innovations embedded into this highly complex urban underground construction project. [ABSTRACT FROM AUTHOR]

Developing large‐scale tunnelling projects in orogenic regions implies enormous technical challenges. Las Leñas International Tunnel Project through the Andes Main Cordillera of Chile and Argentina has been a long‐awaited infrastructure project, whose geological and topographic settings suggest several complex singularities to be considered, analyzed, and assessed during its development. Throughout the course of this feasibility study, the complex geological subsurface interpretation offers a broad spectrum of technical demands to be fulfilled. The overburden conditions, the presence of certain lithologies such as expansive clays or soluble evaporitic sequences, along with regional stress assessment, are major technical challenges. Through extensive geological, geotechnical, and hydrogeological mapping, subsurface 3D modelling interpretation, along with numerical analysis and its relationship with similar projects in the region, brittle, and plastic behaviour are analyzed. A wide range of modern techniques are used to assess those mentioned tasks, which enable an extensive comprehension of the geological and geotechnical conditions of the area. The purpose of this contribution is to enrich the knowledge on geological and geomechanical challenges faced in large tunnelling infrastructure projects in high‐mountain environments and what specific lessons may arise from them for similar future projects. [ABSTRACT FROM AUTHOR]

Cunoașterea cu precizie a sferei de cuprindere ce aparține unui domeniu sau ramuri de drept este o condiție indispensabilă evoluției oricărei ramuri din sistemul dreptului. Este și cazul dreptului mediului. În pofida diferitelor dezbateri asupra denumirii corecte a ramurii preocupate de protecția factorilor de mediu, lansate în spațiul doctrinar încă din momentul apariției sale, astăzi tot mai mulți specialiști dedicați domeniului utilizează sintagma „dreptul mediului” atunci când se referă la relațiile juridice constituite cu ocazia protecției juridice a mediului, dezvoltării, conservării și folosirii raționale a tuturor componentelor de mediu, inclusiv și cele antropice. Cu toate acestea, actualmente mai există unele controverse în privința certitudinii segmentului juridic de preocupare a ramurii de drept a mediului, fiind adesea confundat cu cel al științei ecologia, suprapus chiar la nivel de abordare științifică și didactică. Din respectivul considerent, am decis ca prin studiului de față să punem capăt discuțiilor ce complică și mai mult lucrurile, încercând a arăta că ecologia și mediul, respectiv, dreptul mediului sunt domenii distincte, deși foarte apropiate, corelate și coexistente în sistemul dreptului.

Small‐diameter tunneling in hard rock is increasingly widespread due to the need for new and longer utility tunnels comprising sewer, stormwater, freshwater, or hydropower as well as cable tunnels and casings for pipelines transporting gas or hydrogen. Utility tunnels have to deal with a wide range of geological settings, like small overburden, weathered rock, rock–soil transitions, as well as fractured or intact hard rock with high strength and abrasivity. A database has been created including 35 hard rock projects with diameters between 1 and 5 m as well as more than 70,000 m of tunnel alignments, with a median drive length of less than 500 m. Challenges in creating it and some early interpretations based on the contents of the database are presented. Details about an exemplary pipe jacking project in basement rocks in Brittany, France, are given. The large variety in this small‐diameter range in hard rock includes different TBM types, cutterhead designs, cutter types, and geotechnical conditions. Potential pitfalls in small‐diameter TBM data analysis are shown and general drive parameter trends and penetration prediction approaches are presented and set in relation to the geotechnical conditions. Our analysis shows that difficult ground conditions do not only incorporate rocks with very high strength, but also generally weak rocks like schist or limestone could be responsible for low penetration rates and high thrust forces. [ABSTRACT FROM AUTHOR]

Geological models are commonly used to predict the position of relevant geological features, such as rock types or faults in the subsurface. These models can contain significant uncertainties, as the geological input parameters are often not perfectly known. Predictions of geological features, for example, on the level of a tunnel during an excavation process, are therefore uncertain. This work shows how these uncertainties can be estimated using probabilistic concepts. Furthermore, an approach is presented to automatically adjust the geological model predictions using measurements of the tunnel boring machine (TBM) operation. To this aim, the geological forward model is combined with a measurement model and both are integrated in a probabilistic machine learning framework. This integration enables a Bayesian inference process using computational methods, enabling an update of the parameters of the geological and measurement models. Based on the inferred parameter distributions, the model predictions on the tunnel level are subsequently updated. The application of the concept in a simple schematic application shows that such a combination can accurately and precisely predict features ahead of the operation within the limits of the model capabilities. In future work, the methods need to be tested with a real case study to evaluate the accuracy of predictions using real‐world TBM data and more complex geological models. The framework presented here could directly be extended to this purpose. [ABSTRACT FROM AUTHOR]

Construction of the Verbund project Limberg III pumped storage power station is currently underway in the area of the Kaprun/Salzach power station group. Preliminary work started on 6 April 2021, the main construction work started on 7 January 2022 and the overall facility is scheduled to be commissioned the end of 2025. Kaprun has a long history in the construction of power stations. The Kaprun storage power stations in the 1950s were an outstanding engineering feat and is symbolic of the reconstruction efforts that took place in Austria in the wake of World War II. The power station facilities at the main and upper stage have been in existence since the 1950s and have since been continuously expanded. From 2006 to 2011 the all‐year‐round reservoirs Mooserboden and Wasserfallboden were extended to include the Limberg II pumped storage station. The group is currently expanding the Kaprun/Salzach power station group by building the Limberg III pumped storage station, for which the same design as Limberg II has been adopted for implementation purposes. In addition to the significant logistical challenges posed by the high mountain location of the construction site, this report also covers the tunnelling systems. [ABSTRACT FROM AUTHOR]

Scale formation in water drainage systems occurs in diverse forms. In tunnel drainage systems in particular, calcium carbonate deposition can significantly impair water discharge, resulting in costly maintenance work and tunnel closures. This review paper presents and discusses the state of knowledge as well as the current challenges regarding scale formation in tunnel drainage systems in terms of typification, parameters controlling formation, such as hydrochemistry, interfacial phenomena, microbial activity, and countermeasures, such as appropriate adaptation of construction materials, drainage design, inhibitor use and cleaning. Detailed knowledge of the case‐specific scale formation environment and the scaling capacities of the waters provides the basis for the tailored development and evaluation of suitable strategies for successfully reducing maintenance efforts and tunnel closure. For this purpose, time‐ and site‐resolved monitoring of the composition of the solid phases, waters and the tunnel atmosphere during the implementation of the construction project and during the operation of the tunnel is paramount. [ABSTRACT FROM AUTHOR]

A field test was carried out in Koralmtunnel in order to enhance process understanding and to optimize the drainage system in a tunnel section that is complex in terms of hydrochemistry, water inflow and mineral (calcareous scale, iron ochre) and biological (microbial mats) deposits. The field test comprised three test fields with different system components and flow characteristics. The development of critical waters and deposits was recorded by continuous measurements of relevant water and air parameters by means of autonomous sensors/data loggers. Furthermore, the components were "forensically" examined with respect to scale formation. The experiments show the crucial importance of gas exchange (CO2, oxygen ingress), filling level (flow geometry/regime), residence time of waters and water‐air interaction in the drainage system. The type, material consistency, and amount of scale and biofilms depend significantly on specific gradients. Floating scale crusts formed in stagnant sections, biofilms and iron ochre deposits of soft consistency formed at higher flow rates. Seepage packs and siphons turned out to be potential sediment traps with decreasing flow‐through with no access. Drainage hoses and dimpled membranes tend to be beneficial because they can prevent air exchange at relatively high flow rates. High CO2 partial pressure within these components (measured and modeled) inhibits carbonate precipitation. The drainage system is locally designed as a series of direct cross‐drains with simple flow paths, restricted air exchange, precautionary cleaning access, and optional water hardness stabilization (liquid conditioning). [ABSTRACT FROM AUTHOR]

This article analyses and discusses the current state of the art in the development of digital ground models in tunnelling. Following a review and discussion of the literature research combined with interview responses, a deficit analysis was performed. It shows why current projects mainly work with models and software that function as isolated solutions. A lack of software developments and limited collaborative work mean that the effects of current findings cannot immediately be implemented in models. Accordingly, the enormous potential of full coaction can only be imagined. A further problem is the lack of loss‐free data exchange across varying project phases and participants. Science is already moving in the right direction with the goal of harmonising the basic systematics. Finally, requirements for a digital ground model are formulated, and in combination with collaborative working and improved communication, these result in a large number of advanced possible applications. [ABSTRACT FROM AUTHOR]

In tunnelling, the geological documentation comprises the daily recording and processing of various data for continuously assessing the geological–geotechnical conditions on‐site. One of the core tasks is the documentation of the tunnel face area. With Geodata's Tunnel Mapper, a new measuring system is presented enabling a highly automated data acquisition and the processing of a geo‐referenced three‐dimensional (3D) tunnel face model. Versions of the measuring system for both conventional and mechanised tunnelling have been developed. From the 3D model, high‐quality digital products as well as geometric and geological parameters can be derived, which serve as a basis for decisions on‐site. The data can then be integrated into the geological information system TUGIS.NET of Geoconsult, merged there with other data and further (geologically) evaluated, analysed and visualised. A spatial model that has been interpreted and quantified by the geologist can be established and used for target/actual comparisons and forecasts. The model can be transferred into building information modeling (BIM)‐compatible data structures for integration into an overall BIM model of the project. The further automation and digitalisation of the geological documentation and the full documentation (geometry and geology) of the face area are achieved in the interaction of the systems mentioned. [ABSTRACT FROM AUTHOR]

The year 2022 marks the 100th anniversary of Dr Walter Biese's admission to the German Geological Society. Biese, whose life and work this paper is intended to commemorate, was a geologist, palaeontologist and speleologist from Berlin. He is considered a pioneer of research into the genesis of the gypsum and anhydrite caves in the southern Harz region and critically examined the formerly popular cave river theory. During the Nazi era, Walter Biese was banned from his profession due to social democratic activities. In 1934 he emigrated to Switzerland and from there to Chile in 1937. Walter Biese continued to be active in geology, palaeontology and speleology in these two countries. In Switzerland he compiled a cave register, while in Chile he first worked for a mining company and then as an independent geologist and on behalf of the government, mainly in the field of raw material exploration and regional mapping. In addition, he dedicated himself to palaeontology, botany and zoology, especially malacology. In 1959, he was awarded honorary membership of the Federation of German Cave and Karst Researchers. [ABSTRACT FROM AUTHOR]

To increase the use of geothermal energy in Bavaria, the subsurface, which serves as a reservoir, must be explored as precisely as possible. In the projects of the Geothermal‐Alliance Bavaria, the most promising areas for geothermal exploration in Bavaria were characterised based on an extensive geomechanical laboratory testing program which was carried out on both drill cores and analogue samples from quarries. In the North Alpine Foreland Basin (SE Germany), the geomechanical test results on Upper Jurassic carbonate rocks show a high heterogeneity. On the contrary, in the Franconian Basin (NE Bavaria) the geomechanical properties of granite analogues are rather homogenous. For the numerical simulation of the borehole stability, the determined parameters from ultrasonic‐ and compression tests serve as input parameters for different scenarios. For both locations, the determination of the failure depth around the borehole and the stress distribution in the near‐field of the borehole were accomplished. In the North Alpine Foreland Basin, the borehole stability decreases with increasing depth. For all scenarios in NE Bavaria, the borehole stability is very low. In the future, the determined parameter ranges will allow to validate already existing models and to develop new ones. This will enable a better knowledge of the sedimentary and crystalline reservoirs and a more effective use of geothermal energy in Bavaria. [ABSTRACT FROM AUTHOR]

In Southern Germany, geothermal wells target Upper Jurassic carbonates, formerly referred to as Malm, below the Northern Alpine Foreland Basin (NAFB). In the northern, shallower carbonates (3000 m depth), e.g., in the Munich area, hydrothermal systems prevail, and wells yield proper flow rates. Deeper carbonates (< 4000 m) towards the south indicate a petrothermal system due to a decline in porosity and permeability. Inexplicably, fractures only contribute poorly to larger flow rates. This sets the goal for the project Dolomitkluft to analyse the rock mass for options countering low flow rates in two geothermal wells at Geretsried, Bavaria. Therefore, 20 m drill cores from 4600 to 4715 m total vertical depth (TVD) depict the initial structure of the rock mass: the rock parameters, the discontinuity network, and the in situ stresses. Alternating homogeneous, micritic, strong, to inhomogeneous, porous, weak limestones and massive, crystalline dolostones define the stratigraphy. Five joint sets from the cores can be distinguished into the bedding, two paleo anti‐ and synthetic normal faults and two recent strike‐slip faults. The latter, in combination with core disking, allows exclusively a strike‐slip (SS) stress regime and delimits the ratio to at least SH : Sv : Sh = 1.7 : 1.0 : 0.7. According to the results, including dilatation‐ and slip‐tendencies, drill trajectories of prosperous geothermal wells should head ESE/WNW, perpendicular to SS‐faults, and avoid the presence of normal faults. [ABSTRACT FROM AUTHOR]

Geothermal energy applications are seen as one key element for a successful heat transition in Bavaria. But there are still some barriers for a further development. To minimize these barriers the joint research project Geothermal Alliance Bavaria (GAB) is established. One important issue to foster the implementations of geothermal projects is the assessment of geothermal load prediction in the South German Molasse Basin (SGMB). This includes, aside from a reservoir temperature prognosis, an accurate description of the hydraulic properties of the Upper Jurassic Malm reservoir. Hydraulic test analyses are conducted in the framework of the GAB to obtain specific information about the hydraulic productivity of the reservoir. Results from these analyses show a decrease of rock permeability in southern direction within the reservoir. Because the spatial distribution of hydraulic test data is limited, the porosity of the reservoir is assessed by borehole core tests and logs interpretation. A trend of matrix porosity decrease with depth is recognised and correlates with the hydraulic test results. Based on these findings and combined with further information the Upper Jurassic reservoir could be classified in separated zones of similar production rates, which can now be used for a thermal output prognosis for the Bavarian part of the SGMB. To spatially expand these prognoses more data must be investigated in the next research phase of the GAB. [ABSTRACT FROM AUTHOR]

For the transition to sustainable heat sources, storage infrastructure is required to provide heat evenly throughout the year. Solar heat is typically produced in the summer and can be stored in underground heat reservoirs for the winter. Flooded coal mines, e.g., are potential heat reservoirs. To assess whether the geomechanical integrity of a colliery and the surrounding rock mass are affected by seasonally stored heat, a numerical case study was performed at "Zeche Dannenbaum" in the Ruhr valley, Germany. During summer, hot water was injected into level 8 of the colliery while cold water was produced from level 4. This process was reversed in winter. Detailed subsurface models of the colliery, rock mass and tectonic faults were used to numerically simulate the cyclical changes in pore pressure and temperature and the resulting stress changes. The displacement of the land surface, and geomechanically critical regions in the rock mass were derived. Moreover, the reactivation potential of the fault zones and the risk of induced seismicity were evaluated. The high injection temperatures induce strong thermoelastic effects, which could potentially lead to fault reactivation and induced seismicity. Surface displacements, however, are negligeable. [ABSTRACT FROM AUTHOR]

The urgent need to speed up the process of reducing CO2 emissions, as well as to stimulate the production and use of renewable energy demands sophisticated technologies to reach these goals. By developing an advanced drilling technology, the EU H2020 project ThermoDrill set itself the target to make the utilization of geothermal energy more economical. The new drilling technology is based on the combination of rotary drilling and high‐pressure fluid jetting. Rock mechanics largely contributes to the achievement of the common purpose of the project. Especially the investigation of the rock destruction process due to the combined hydraulic and mechanical impact plays a major role. The results are based on extensive experimental research concerning rock fracture under varying conditions. Additionally, various methods of crack detection are applied to identify the underlying mechanisms of the drilling technology. As a result, the specifications of the developed prototypes are to a considerable amount based on the rock mechanical findings. The huge potential of the advanced drilling technology is supported by the results of laboratory tests and field tests. [ABSTRACT FROM AUTHOR]

Based on multi‐scale and multi‐disciplinary measured data, gathered at the Geretsried geothermal site, a 3D reservoir model of the deep and fracture‐controlled Upper Jurassic carbonates in the North Alpine Foreland Basin is generated in this work. An efficient methodology is developed to numerically simulate the coupled reservoir processes of fluid flow, heat transport and thermoporoelastic stresses resulting from possible geothermal doublet operating schemes with cold fluid injection and production profiles in an enhanced naturally fractured reservoir. A variety of numerical experiments is conducted to study the reactivation potential and dilation tendency of the fracture and fault system. Simulation results show the spatiotemporal evolution of the thermoporoelastic stresses and the zone affected after 50 years of geothermal doublet operation. From these simulations, the thermoelastic response of a geothermal doublet operating with 60 °C fluid injection temperature and 20 l/s flow rate translates into a maximum induced thermal stress of around 49.4 MPa near the injection well. In terms of a long‐term reservoir performance and fault and fracture reactivation potential, the findings reveal a negligible risk to a sustainable geothermal doublet operation. [ABSTRACT FROM AUTHOR]

High‐pressure water jet drilling technologies are widely used in the drilling industry. Especially in geothermal and hard rock applications, jet drilling is, however, confronted with several limitations like lateral length, hole size, steerability and jetability of the reservoir rock. The application of jet drilling technologies in the field can only be estimated based on the experience of the operator and surface experiments imitating downhole conditions. To predict a successful jetting operation in the field, a modelling framework has been developed, which considers operational and technical parameters as well as reservoir rock specifications. The framework consists of calibrated models describing downhole hydraulics and mechanics during the jetting operation and estimates the required technical equipment to successfully penetrate the reservoir rock and the maximum achievable lateral length for various hole configurations. The modelling framework is applied on a theoretical case study. [ABSTRACT FROM AUTHOR]

The BIM pilot project "New Köstendorf‐Salzburg Line" for ÖBB‐Infrastruktur AG covers a new twin‐track section about 21 km long involving a wide variety of different engineering structures and a corresponding need for close interdisciplinary collaboration within a sensitive project space. The pilot project successfully achieved its objective of generating a largely software‐independent overall model and transferring the knowledge gained to the Employer's Information Requirements and subsequently to a BIM execution plan. In addition to internal coordination meetings, a preliminary external meeting took place to discuss the model elements required for a government agency as part of an approval process and the availability of such elements by means of direct access to the model. By adopting an integrated, collaborative approach to project management, it was possible to define extensive procedures and workflows adapted to the needs of the respective project partners for the single‐discipline models (specialist models) and to coordinate an overall federated model. The results of the co‐ordinated overall model show the ample opportunities afforded by a parameterised ground model for transparent risk and project assessment, paving the way for a holistic, phase‐based infrastructure information model. In this regard, the authors felt that it was important to adapt the project partners' established internal procedures only minimally and to translate them into BIM‐compatible, cooperative workflows. [ABSTRACT FROM AUTHOR]

Applications of seismic measurements for the prediction of hazard zones are applied practice in many tunnel drives in rock mass today. Next to a large exploration range and accurate localisation of discontinuities, seismic data provide attributes for a comprehensive characterisation of the ground conditions. A good synchronisation of all technical components is required to obtain optimum data quality and quantity while the tunnel excavation is not obstructed thereby. Firstly, the signal source must feed as much energy as possible into the rock in a very short time. Secondly, continuity of the signal generation with constant quality and its precise timing by means of wireless data transmission also ensure a reliable measurement process. Artificial intelligence is used to determine the quality of the recorded data already in the tunnel and feedback is given to the user keeping the data quality high. From the tunnel site, recorded raw data can be transferred to a cloud, from where an authorised processor collects them, wherever in the world. An immediately started data processing delivers a result within an hour that includes a geological forecast of up to 150 m of heading, depending on the rock mass condition. In addition to data quality, the quality of the results is crucial. Therefore, techniques are currently under development using machine learning to correlate and analyse seismic attributes with geological properties. This should lead to a more objective evaluation of the geological forecast in the future. [ABSTRACT FROM AUTHOR]

The extension of the Metro B line in Lyon represents a technical challenge combining difficulties with very few equivalents in pressurised TBM history. Alluviums with wide porosity and high permeability (up to 10–2 m/s) imply a risk of slurry loss leading to ground instabilities. To mitigate geological risks without using heavy ground treatment, two lines of research were followed: i) A slurry development program, aiming to define and validate technical mud formulae reducing the losses and ensuring the continuous confinement pressure. Two types of innovative slurries were to be defined, a "technical" one for horizons with high permeability, and an "emergency mud" to secure the tunnel and constructions in the event of a sudden slurry loss. ii) The use of a variably density TBM to use these technical slurries with a classic and an independent auxiliary hydraulic circuit. In addition, an embedded emergency mud supply was added to the TBM. The first phase implemented the slurry development lab, which consisted in the characterisation of a wide range of products entering in the slurry composition such as bentonite, mineral or organic clogging agents, polymers, gels, etc.. The slurry formulae were then tested under pressure in permeameters of two different sizes. Solutions clogging the porosity and sustaining mud and air pressure have been developed. The execution phase proved, that the developed solutions were giving the expected results regarding controlling slurry losses in the ground, maintaining front confinement pressure and reducing surface settlement below expected values in a dense urban area. [ABSTRACT FROM AUTHOR]

The S1 Donau‐Lobau tunnel closes the gap in the road network around Vienna. Its two tunnel tubes run under the Danube and the Donau‐Auen National Park, with the provision that no work is allowed to take place on the surface of the site. The (hydro‐)geological subsurface conditions in the project area can be described as "difficult". The tunnel project must also meet all safety‐related requirements that arise during construction and operation, while at the same time minimizing the environmental impact. This article describes the essential special civil engineering and tunnelling measures in connection with the local subsoil conditions. It outlines the geotechnical exploration goals required for the structural tendering and detailed planning as well as for limiting the subsoil risk. Just obtaining the necessary permits for the exploration work required extensive preparatory work. As a result, both the exploration programme and the tunnel itself have been further adapted. The approved explorations were completed in the shortest possible time in compliance with extensive environmental requirements during a single winter season. [ABSTRACT FROM AUTHOR]

The use of geophysical methods for the planning of complex underground structures such as deep tunnels has made significant progress in the last two decades. The realization of large underground construction projects in complex geological environments has led to an increase of geophysical exploration during excavation activities, drilling, and geological documentation. The aim is to continuously update and improve the geological model in order to identify and mitigate potential risks. Flexible planning of geophysical measurements and their fast and efficient implementation are required to minimize the impact on ongoing construction works. During construction of the Semmering Base Tunnel geophysical measurements were and are used to supplement exploratory drillings and tunnel documentation. This paper presents results from the construction lots SBT1.1 (Gloggnitz) and SBT3.1 (Grautschenhof) with an emphasis on carbonate prediction, and from the Göstritz cavern where sudden water ingress required an update of the geologic model. For each assignment a tailored‐made geophysical methodology was designed and applied. [ABSTRACT FROM AUTHOR]

This paper examines the possibility of using excavated material with system‐related admixtures as a substitute construction material, considering the current rules and regulations in the field of landfilling or disposal. In addition to conventional injections with bentonite‐ and cement‐containing suspensions, which always require longer setting times and are relevant for classification during disposal with sulfate values in the eluate, fast‐setting multicomponent resins are suitable for filling or consolidation, e.g. fast‐reacting, high‐foaming silicate resins, polyurethane resins for stopping water ingress, or rubber‐elastic, versatile 3‐component acrylate gels. However, the discussion is currently focusing on tunnelling compounds to which foams or resins have been added and which, according to Systal's "system‐related admixtures", are to be remunerated as special services. This paper deals with the question how to deal with the excavated material contaminated with organic matter under soil protection law and waste law. On the basis of the results of laboratory tests, the question arises as to whether tunnel excavation with a few percent of organic, system‐related admixtures would not make an excellent substitute building material in the sense of the draft substitute building materials ordinance. [ABSTRACT FROM AUTHOR]

Si dans le contexte environnemental actuel il devient difficile d’identifier une nature autonome et indépendante de l’Homme et de la société, quel est alors l’objet des sciences de la nature ? Nous proposons d’apporter ici une réponse à partir d’une enquête socio-anthropologique réalisée dans le cadre d’un projet interdisciplinaire à l’initiative des sciences de la Terre. Celle-ci nous a conduit à pointer l’importance du rapport au terrain dans la culture du géologue, même si ce terrain est souvent mis au second plan (ou disparaît même parfois) des publications en sciences de la Terre. Cette approche socio-anthropologique de la géologie, révélant la place du sujet dans la formation de la connaissance, permettra de conclure sur l’importance d’une réflexion pluridisciplinaire sur l’ethos du chercheur face aux enjeux environnementaux d’aujourd’hui.

The Artificial Ground Freezing (AGF) has demonstrated its versatility as an effective approach for both temporary ground stabilization and ground water control in almost all types of saturated soils. This paper describes the use of a closed circuit freezing system in the construction of four cross passages. The passages connect 4.8 km long twin road tunnels that have recently been constructed at depths of up to 60 m under Suez Canal in Ismailia, Egypt. The paper starts by describing the ground conditions at the locations of the cross passages and by presenting the results of laboratory tests conducted on unfrozen, frozen and thawed soil specimens. The main design criteria considered in designing the freezing works are discussed and the freezing and cross passages construction works are described. The frozen body was carefully monitored during the freezing process and construction of passages. Records of the adopted monitoring program are presented and discussed. Significant observations that contribute to effective planning of future freezing works are also presented. [ABSTRACT FROM AUTHOR]

On the basis of a case history of a pumping storage which is endangered by a slow moving landslide, the interaction of the reservoir operation and the deformation behaviour of the landslide will be discussed in this paper. Comprehensive measurements as well as theoretical investigations, which had been performed to understand the determining factors for the deformation behaviour of the landslide, will be discussed. Based on these investigation results a warn and alarm plan as part of the safety concept for the storage had been developed. [ABSTRACT FROM AUTHOR]

The characterisation of rock as a foundation for hydropower plants in general and dams in particular is highly complex and requires a great deal of experience on the part of the geologists involved. Geology cannot be studied remotely; it requires geological field surveys and investigations. This paper describes the aspects to be considered, the planning of the investigations and the degree of detail needed at the various planning phases from the field geologist's perspective. It also highlights the internationally recognised methods of investigation used for large‐scale projects and describes how the results are documented and recorded. It concludes by briefly outlining the soft factors which constitute an integral part of successful geological feasibility studies. Geology is an "inexact" science that requires extensive experience in order to generate the most realistic ground model possible. For this reason, a clear distinction must be made between facts (basic data) and their interpretation (experience). Furthermore, it is important to consider what other conclusions can be drawn from surveying the subsoil. [ABSTRACT FROM AUTHOR]

As a result of several feasibility studies from which sound economic and technical arguments emerged, the decision was made to construct a new headrace system for the Rodundwerk I consisting of a low pressure tunnel, a shallow pressure shaft parallel to the surface slope and a subsequent high‐pressure penstock gallery. The new distribution pipeline was designed as a concrete‐encased gravity abutment. Construction started at the beginning of May 2020 and since then excavation work has progressed according to plan. Particular attention had to be addressed to the impact of construction operations on the existing power plant structures. Hence, a detailed monitoring concept was established concerning the vibration transmission in the rock mass. Excavation works are carried out partly by tunnel boring machine, partly by drilling and blasting and, once the critical threshold of vibration has been reached, by alternative methods. By continuously adjusting the blasting parameters (charge amount, ignition timing), it was possible to minimise the detonation‐related effects in the vicinity of the existing structures. [ABSTRACT FROM AUTHOR]

Dutch geologists and archaeologists disagree about the time the Flevo-lakes in the Wet Heart of the Netherlands were connected with the western part of the Waddenzee. Geologists hold the strong view that this connection originated in the centuries bc. Archaeological research revealed, however, that the pre-urban development of the city of Amsterdam did not start until the last quarter of the 12th century ad. This urban development has been considered as an indication that the shipping route between the mouth of the river Amstel and the Waddenzee had improved shortly before. Therefore, archaeologists are convinced that the improvement of this shipping route was forced by the All Saint's flood of 1170. To the west of Schagen, the sea is considered to have broken up the coastal barrier which led to the development of the Zuiderzee. Because of the etymological relation between the names Flevo and Vlie, the Flevo-lakes must have been already connected with the Waddenzee in the Roman period. Near Medemblik, however, the water did not become brackish before the 8th century ad and more to the south not earlier than the 9th century. Therefore, drainage must have been the main function of the connection between the Flevo-lakes and the Waddenzee for centuries. From historical documents it is known that somewhere around Stavoren a large amount of land was lost to the sea in 1170. Together with the swift development of Amsterdam it is likely that the Zuiderzee came into being after 1170. A breakthrough of the coastal barrier to the west of Schagen at that time, however, is unlikely. In 1170 there was some damage in the northern part of the province of Holland caused by a storm surge, but the loss of land was limited due to the building of several dikes. [ABSTRACT FROM AUTHOR]

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In the course of the preliminary planning of the new Gelnhausen–Fulda railway line which is part of the railway project Hanau–Würzburg/Fulda, two route options with tunnels, bridges, cuts and embankments are to be investigated and assessed as efficiently as possible with regard to potential geotechnical risk areas. Due to the geological and hydrogeological conditions within the north‐eastern Hessian Buntsandsteingebirge, several groundwater levels, landslides in tunnel portal areas and karstification structures are to be expected on the two route options, each of which is approx. 45 km long. In order to obtain detailed and, above all, large‐scale knowledge of geotechnical hazards of each route = in the preliminary stage of the exploration programme, geophysical surface investigations are a cost‐ and time‐optimized exploration method in addition to standard drilling. These findings as well as existing subsurface information are combined by means of BIM, so that risk areas can be identified at an early stage of the project and taken into account when selecting the most affordable route. [ABSTRACT FROM AUTHOR]

Copyright of Synergies Algérie is the property of GERFLINT (Groupe d'Etudes et de Recherches pour le Francais Langue Internationale) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper discusses the design and construction of a fault zone of the OeBB Koralmtunnel lot KAT3. Due to the experience gained during the advance of the parallel‐situated southbound tunnel and the aim to minimize the geotechnical hazard for the subsequent excavation of the northbound TBM bore, an extensive redesign regarding the excavation‐concept and ‐method was performed. Five different alternative solutions have been subject to a risk analysis to optimize the required measures and to minimize the cost‐effective risks and hazards to an acceptable level. The set of measures, which was evaluated and juxtaposed, contained solutions for strengthening the rock mass with grouting from the TBM and from aside the bore, conventional tunnelling and backfill with a top heading or full‐face excavation. Finally, the fault zone has been excavated with a conventional top heading drive from a nearby‐situated cross‐passage. Subsequently this tunnel stretch has been excavated by TBM without any construction delay. The paper focuses on highlighting the importance of a consequent application of the observational method and thereof derived measures in the context of a geotechnical safety management plan for controlling the residual risks. [ABSTRACT FROM AUTHOR]

One of the major fault zones in the Semmering area runs along the Auebach Valley. In this fault zone a combination of soft fault rocks and water bearing hard rocks led to extremely challenging conditions in the design and execution of the tunnel. In difficult conditions, overlapping exploratory drillings in front of tunnel drive are essential to improve the geological‐hydrogeological model and to assess geotechnical risks. However, in the encountered geological‐hydrogeological conditions, the well‐established exploratory drilling methods reached their limits. Despite the ongoing risk analysis, a very large‐scale water and ground inflow with subsequent tunnel face collapse and development of a sinkhole on the surface occurred during the tunnelling. This paper describes the causes of the incident and the development of procedures to cope with the problem. In addition to the geological‐geotechnical analyses, the article also discusses the limitations of geotechnical surveillance in complex heterogeneous rock masses. [ABSTRACT FROM AUTHOR]