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Building and ground settlement due to construction dewatering is a well-studied topic. However, most previous investigations have not considered the barrier effect of an adjacent underground structure on the drawdowns and resulting settlements. In this study, the barrier effect and its influence during construction dewatering for a metro station foundation pit is investigated. There are five aquifers at the foundation pit site, and a row of buildings supported on pile foundations, which act as an underground barrier to flow, is present on one side of the pit. On the other sides, there are no deep underground structures to impede groundwater flow. Field monitoring of the groundwater level drawdown, diaphragm wall movement, and ground and building settlements on both sides of the pit was carried out during dewatering. The results indicate that on the side with the pile foundations, the groundwater level drawdown, ground settlement, differential settlement, and angular distortion of building incurred by dewatering were relatively greater, but the diaphragm wall movements were relatively smaller. The effect of preexisting barriers should be considered in the assessment of construction dewatering-induced drawdowns, soil settlements, and building movements. [ABSTRACT FROM AUTHOR]

In the random field model's consideration of the spatial variability of soil, soil properties at different locations play different roles in the reliability analysis of the foundation. Investigating the importance distribution of the random field through reliability sensitivity analysis (RSA) is beneficial for understanding how the random field affects the reliability of the foundation. However, many existing RSA methods for the random field model are deficient in terms of efficiency, accuracy, and applicability under complex engineering conditions. Consequently, this study proposes an efficient RSA method for the random field model based on the Karhunen–Loève (KL) expansion method and the first-order reliability method (FORM) to identify the important random field domain in foundation engineering. In the proposed method, the mean reliability sensitivity index (MRSI) is extended to a random field model of continuous form to characterize the importance distribution of the random field. The MRSI is analytically derived based on the results of the KL expansion method and the FORM without additional limit state function (LSF) calculations. Subsequently, the important random field domain, in which the variation of the mean of the soil property contributes significantly to the reliability index, is identified based on the MRSI. Last, two foundation engineering examples that consider the cross-correlated random fields of cohesion and friction angle, including strip footing on single-layer soil and pile in multiple-layer soil, were used to verify the proposed method. The results showed that an important random field domain with a small area dominates the variation of the reliability index of a foundation, and important random field domain area increases with autocorrelation distance (ACD). This innovative identification method holds great engineering significance, because it allows geotechnical practitioners to gain a comprehensive understanding of the failure modes and foundation treatment areas of foundations in spatially varying soil. In the random field model's consideration of the spatial variability of soil, soil properties at different locations play different roles in the reliability analysis of the foundation. Investigating the importance distribution of the random field through RSA is beneficial for understanding how the random field affects the reliability of the foundation. However, many existing RSA methods for the random field model are deficient in terms of efficiency, accuracy, and applicability under complex engineering conditions. Consequently, this study proposes an efficient RSA method for the random field model to identify the important random field domain, in which the variation of the mean of the soil property contributes significantly to the reliability index. Two foundation engineering examples that consider the cross-correlated random fields of cohesion and friction angle, including strip footing on single-layer soil and pile in multiple-layer soil, were used to verify the proposed method. The results showed that the innovative identification will allow geotechnical practitioners to gain a comprehensive understanding of the failure modes and foundation treatment areas of foundations in spatially varying soil. [ABSTRACT FROM AUTHOR]

Enhancing the dynamic properties of expansive soils using cementitious materials has attracted the attention of many researchers over the past few decades. Supplementary cementitious materials (SCMs) can be used as partial substitutes for cement owing to their pozzolanic activity that further improves the mechanical performance of cement-stabilized soils upon curing. In this study, the effect of cement and zeolite incorporation on the mechanical behavior of expansive clay was quantified using the pressure wave velocity (Vp) indicator obtained from ultrasonic pulse velocity tests performed at different curing times. Furthermore, a polynomial model was developed to establish the relationship between Vp and zeolite replacement levels at specific curing times and cement contents. The results show that a polynomial function captured the decreasing trend of Vp upon the increase in zeolite at curing times below 14 days. Additionally, the developed equation explained the upward trend of Vp owing to the pozzolanic activity of zeolite at later curing times with an accuracy of over 92%. The coefficients of the polynomial model also increased with the increment of the cement percentage which conformed to the consecutive rise in Vp. Ultimately, the polynomial coefficients were expressed in terms of cement content and curing time using the Volterra series. Using this model, the optimum percentage of cement replaced with zeolite (Zopt), the efficiency of using Zopt instead of cement, and the percentage of zeolite replacement to achieve equivalent Vp of cemented clay samples (ZC) were estimated. The findings of this study contribute to promoting geotechnical sustainability by replacing cement with zeolite that has a considerably lower environmental footprint. Clay is a type of soil that can be found in many construction projects. For instance, many roads and buildings' foundations are constructed on clay soils. To ensure the necessary strength of the clay under the main structure, the soil should often be stabilized using adhesive construction materials such as cement. Interestingly, a portion of the cement could be replaced with other minerals not only to improve engineering performance but also to promote sustainability by lowering cement consumption. In this study, the effect of zeolite as a partial replacement for cement on the strength of clay soils was experimentally evaluated. The effect of various design parameters, such as cement replacement level and curing time, on the stability of clays was investigated using an advanced technique called the ultrasonic pulse velocity (UPV) test. Furthermore, a simple mathematical model was proposed based on the experimental results to help engineers design the stabilization plan and timely decide about the next steps of the construction process. [ABSTRACT FROM AUTHOR]

As a key guarantee and cornerstone of building quality, the importance of deformation prediction for deep foundation pits cannot be ignored. However, the deformation data of deep foundation pits have the characteristics of nonlinearity and instability, which will increase the difficulty of deformation prediction. In response to this characteristic and the difficulty of traditional deformation prediction methods to excavate the correlation between data of different time spans, the advantages of variational mode decomposition (VMD) in processing non-stationary series and a gated cycle unit (GRU) in processing complex time series data are considered. A predictive model combining particle swarm optimization (PSO), variational mode decomposition, and a gated cyclic unit is proposed. Firstly, the VMD optimized by the PSO algorithm was used to decompose the original data and obtain the Internet Message Format (IMF). Secondly, the GRU model optimized by PSO was used to predict each IMF. Finally, the predicted value of each component was summed with equal weight to obtain the final predicted value. The case study results show that the average absolute errors of the PSO-GRU prediction model on the original sequence, EMD decomposition, and VMD decomposition data are 0.502 mm, 0.462 mm, and 0.127 mm, respectively. Compared with the prediction mean square errors of the LSTM, GRU, and PSO-LSTM prediction models, the PSO-GRU on the PTB0 data of VMD decomposition decreased by 62.76%, 75.99%, and 53.14%, respectively. The PTB04 data decreased by 70%, 85.17%, and 69.36%, respectively. In addition, compared to the PSO-LSTM model, it decreased by 8.57% in terms of the model time. When the prediction step size increased from three stages to five stages, the mean errors of the four prediction models on the original data, EMD decomposed data, and VMD decomposed data increased by 28.17%, 3.44%, and 14.24%, respectively. The data decomposed by VMD are more conducive to model prediction and can effectively improve the accuracy of model prediction. An increase in the prediction step size will reduce the accuracy of the deformation prediction. The PSO-VMD-GRU model constructed has the advantages of reliable accuracy and a wide application range, and can effectively guide the construction of foundation pit engineering. [ABSTRACT FROM AUTHOR]

It is demonstrated that the application of piezoelectric sensors to metallic bars and strands can enable determining the status of the integrity of these elements through the spectrum of their acoustic excitations. The voltage output of the piezo, secured to metal bars or strands, is fed to the input of a Fast Fourier Transform analyzer, which allows displaying the spectrum of the excitations from which information on the length, overall quality of the metal, and the presence of defects can be obtained. We show that the analysis, performed on several materials and strands of different lengths, could be useful for cases in which visible inspection and/or direct access to the entire body of the metallic elements is not possible. Applications of our study for testing metallic structures embedded in concrete foundations are reported for construction sites. [ABSTRACT FROM AUTHOR]

Designing tunnels in urban areas necessitates an accurate estimation of their construction effects on adjacent structures. This study explores tunnelling impacts beneath raft foundations, focusing on settlement and bending moment variations due to different tunnel depths and soil densities. A verification model validated tunnel modelling with field data, employing a 2D finite element model to assess raft foundation performance above tunnels. It also examines the influence of tunnel depth, soil consistency, and spacing of two tunnels. Key results show raft settlement increasing by over 250% when tunnels are directly below at a 7.5 m depth, regardless of soil density. Soil cover thickness above the tunnel significantly affects the raft's bending moment, with an increase of up to 400% and 300% for 5 m and 7.5 m cover depths, respectively. Final tunnel construction stage settlements varied with soil density. The study also reveals that increasing the spacing between closely spaced tunnels beyond 1.2 diameters reduces both raft settlements and bending moments. These findings emphasize the importance of careful tunnel placement and soil cover management to minimize negative impacts on raft foundations. [ABSTRACT FROM AUTHOR]

The shear creep characteristics of the contact surface between the permafrost and the structure play an important role in the study of the law of deformation and the measures for the prevention and control of pile foundations. In order to study the creep law and the development tendency of the contact surface between permafrost and concrete, it is necessary to establish an accurate creep model. In this study, based on the Nishihara model, a nonlinear element and damage factor D were introduced to establish an intrinsic model of permafrost-concrete contact surfaces considering the effect of shear stress. Creep tests with graded loading of concrete and frozen silt with different roughness at -1°C were conducted using a large stress-controlled shear apparatus. The adequacy of the model was checked using the test data and the regularity of the parameters of the model was investigated. The results show that the creep curves of the contact surface obtained with the improved Nishihara model agree well with the test results and can better describe the whole process of creep of the contact surface of frozen concrete. The analysis of the experimental data shows that: the roughness of the concrete has an inhibiting effect on the creep deformation of the contact surface, When the roughness R varies from 0 mm to 1.225 mm, the specimen corresponds to a long-term strength of 32.84 kPa to 34.57 kPa. For the same roughness and creep time, the creep deformation of the contact surface is more significant with the increasing shear stress τ. The results of the study can provide a theoretical basis for the design and numerical simulation of pile foundations in permafrost regions. [ABSTRACT FROM AUTHOR]

Functionally graded materials (FGMs) are commonly utilized in construction projects. They enhance the performance of functionally graded beams (FGBs) under various loading conditions. Therefore, the incorporation of variable-section FGBs theory into the analysis of structural and soil interactions is crucial for advancing engineering applications. Employing the variational principle and the transfer-matrix method, and considering the shear stiffness of the axially FGB structure itself, along with the continuity and shear strength of the soil, a semi-analytical solution for displacement and internal force of axially FGBs on Pasternak foundation (termed as P–T model) is derived in this paper. The semi-analytical solution is subsequently compared with finite difference solution results from prior studies, affirming the accuracy and precision of the proposed computational theory. The P–T model degenerates to the Winkler–Timoshenko model (W–T model) when the foundation's shear layer stiffness is set to zero. Additional analysis is conducted on displacement and internal force variation when the beam stiffness follows different distribution along the axial direction. The results indicate that an asymmetrical distribution of stiffness on either side of the midpoint could increase the displacement at the middle section. Furthermore, when the beam stiffness adheres to a Gaussian distribution along the axial direction of the beam, a significant increase in displacement at the boundary position of the beam is observed. The proposed method is then integrated with the Mindlin stress solution to evaluate construction impact on an existing tunnel within a foundation pit project in Shenzhen. A comparative analysis of theoretical calculations, monitoring data, and numerical simulation results exhibits substantial concurrence across the three methods. The tunnel's overall deflection adopts an "M" shape, and the computation using the variable-section FGB portrays the existing tunnel's deformation trend with heightened accuracy, diminishing the calculation error from 35 to 8.3% compared to the conventional normal section beam. [ABSTRACT FROM AUTHOR]

This paper aims to analyze and describe the geotechnical behavior of a piled raft foundation of a tall building (53 floors, 172.4 m high) through the monitoring of strains in the building's columns and piles, the stresses at the raft–soil interface, and the foundation settlements. Field and laboratory tests were performed, and associated with axisymmetric and three-dimensional finite element analysis to the assessment of the measured data. The monitoring of the pile strains suggests the occurrence of soil expansion, caused by the raft excavation process, up to approximately 6 months after the excavation was completed. The presence of different soil profiles under the raft, with different mechanical properties, affected the distribution of the foundation settlements and the pile loads. Initially, the average pile loads were concentrated in the perimeter elements, but, as the construction of the building evolved, they tended to become more uniform. The effect of the superstructure stiffness caused successive load redistributions in the columns, which contributed to the maintenance of the maximum angular distortion of the building within the allowable values and reduced the load difference between the piles positioned in opposite soil profiles. [ABSTRACT FROM AUTHOR]

Existing simplified procedures for evaluating soil liquefaction potential or for estimating excess pore pressures during earthquakes are typically based on undrained cyclic tests performed on saturated soil samples under controlled loading and boundary conditions. Under such conditions, the effect of excess pore pressure (ue) dissipation and redistribution to neighboring soil layers cannot be accounted for. Existing simplified procedures treat liquefiable layers as isolated soil layers without any boundary conditions even if dense and loose layers are very thin, permeable, and adjacent to each other. However, redistribution is likely to increase and decrease ue in the neighboring dense and loose layers respectively. Until now, no procedure short of fully coupled numerical analysis is available to estimate the importance of redistribution. This paper presents an approximate analytical procedure for assessing the effects of ue redistribution in (1) soil layers that would have liquefied if they were undrained, and (2) soil layers that would have not liquefied even if undrained. It is found that a layer that is initially assumed liquefied under undrained conditions might not even liquefy accounting for the ue redistribution to neighboring layers. On the other hand, a layer initially assumed to not liquefy can develop significant ue and can even liquefy due to pore pressure migration from the neighboring layers. Thus, accounting for redistributed ue is important for liquefaction consequence assessment quantification, particularly in systems that span the depth of these effects like deep foundations. Migration of u toward the tip of a pile can reduce its capacity, even if the tip is embedded in a dense sand layer. On the other hand, if redistribution can result in the reduction of ue in initially assumed liquefied layers, risks associated with liquefaction might be avoided. A criterion is also developed to evaluate the thicknesses of a layer below which redistribution could prevent liquefaction even if the layer is deemed liquefied according to the existing liquefaction-triggering procedures. Finally, the proposed procedure is illustrated by application to selected shaking events of centrifuge tests involving liquefaction of layered soil profiles. The predictions from the procedure matched the centrifuge test results reasonably. [ABSTRACT FROM AUTHOR]

Pile foundations supporting high-rise buildings are generally subject to cyclic loading because of dynamic loading. The corrosion of steel materials in pile foundations is another major concern, especially for piles in a marine environment. In this study, a series of cyclic and static loading tests on model piles made of fiber-reinforced polymer (FRP) and seawater–sea sand concrete (SSC) and ended in a rock socket were reported. Three structural configurations (FRP tube–confined, FRP rebar cage–reinforced, and centered FRP rebar–reinforced) were adopted for the model piles. Strain along the depth of the piles was measured using fiber Bragg grating (FBG) optic sensors and an advanced distributed optical sensing technique known as optical frequency domain reflectometry (OFDR). Strain distribution, axial cyclic stiffness, and shaft friction mobilization of the piles under static and different modes of axial cyclic loading were analyzed and explored in detail. The test results indicated that the FRP tube–confined model pile showed higher confinement and cyclic capacity and lower stiffness degradation, leading to relatively more stable behavior. A high level of cyclic loading can cause microcracks to form and grow within the pile material, thereby decreasing pile stiffness. The strain profile of all the piles along the depth appeared to follow a similar trend, and fluctuations at certain points led to failure. Cyclic stiffness showed gains initially when cyclic load conditions were below a certain threshold level but degraded when loading was increased beyond it. Moreover, shaft resistance gradually increased with cycles, causing higher mobilization in the upper portion of the socket. The experimental results have provided the first systematic study on the performance of the FRP-SSC composite model piles ended in rock sockets under axial cyclic and static loadings. This will contribute to development of a potential predictive method for pile settlement and capacity for the better design of rock-socketed piles. [ABSTRACT FROM AUTHOR]

This document discusses a research paper that proposes a modified method for evaluating the stability of deep excavations in soft clays. The discussion raises concerns about the proposed method and questions the assumptions made by the authors. It suggests alternative explanations for the observed behavior of excavations in soft clays and criticizes the models used in the study for not accurately representing actual ground movement patterns caused by excavation. The author invites the study authors to respond to these criticisms. [Extracted from the article]

The aim of the small-scale regional engineering geological study of the Czech Republic was to evaluate the relationship between slope gradient and engineering geological zones. The research motivation was to determine the average slope gradient, 25%, 50% (median) and 75% quantiles related to the different engineering geological zones. This scientific information is critical from the perspectives of engineering geology, geotechnical engineering, and foundation engineering because an increasing slope gradient evokes the need to create a cut respectively foundation excavation or another excavation in the geological structure, which increases the probability of occurrence of the problem in terms of differential settlement and bearing capacity of the structures. The research was carried out in the territory of the Czech Republic in 8 Quaternary zones with soil foundation ground and 10 pre-Quaternary zones with rocks and semi-rocks and their eluvia. A significant difference in the statistical characteristics of slope gradients was found in the group of Quaternary engineering geological zones (evaluated group I) compared to the group of pre-Quaternary zones (evaluated group II). The value range of the average slope gradient was 1.65° (16.9%) to 5.89° (60.3%) for the Quaternary engineering geological zones (soil foundation ground), representing 43.4% difference. Whereas for the over-quaternary engineering geological zones (rocks, semi-rocks and their eluvia), the difference was much higher, 3.59° (36.8%) to 9.76° (100%—value determined as a referential because it was the maximum), which is also reflected in a more significant percentage difference of 63.2%. [ABSTRACT FROM AUTHOR]

Foundation pit excavation can cause settlement and displacement of surrounding existing buildings and roads. In order to study the influence of soil unloading on the surrounding buildings during pit foundation excavation, the application of a pile-anchor retaining structure in a deep foundation pit was studied, with the deep foundation pit project of Anhui Bright Pearl Mall as the research subject. Through theoretical analysis, field measurements, and FLAC3D numerical simulations, the supporting structure was comprehensively analyzed. A comparison was made between the measured displacement data and the numerical simulation results of the supporting structure and the surrounding environment during the excavation process of the foundation pit. The results indicate that the model results, obtained through the use of the FLAC3D software for numerical simulations, generally align with the field data. This approach can more accurately reflect the evolutionary laws of soil pressure and deformation during the excavation of the foundation pit. The maximum displacement of the horizontal displacement monitoring point in this project's foundation pit is 25.96 mm, which is less than the monitoring alarm value of 30 mm. The horizontal displacement monitoring of the sidewall of the foundation pit is crucial among them. An analysis of the three major causes of numerical deviation provides valuable insights for the design of deep foundation pit supporting structures. [ABSTRACT FROM AUTHOR]

This paper assesses trending AI foundation models, especially emerging computer vision foundation models and their performance in natural landscape feature segmentation. While the term foundation model has quickly garnered interest from the geospatial domain, its definition remains vague. Hence, this paper will first introduce AI foundation models and their defining characteristics. Built upon the tremendous success achieved by Large Language Models (LLMs) as the foundation models for language tasks, this paper discusses the challenges of building foundation models for geospatial artificial intelligence (GeoAI) vision tasks. To evaluate the performance of large AI vision models, especially Meta's Segment Anything Model (SAM), we implemented different instance segmentation pipelines that minimize the changes to SAM to leverage its power as a foundation model. A series of prompt strategies were developed to test SAM's performance regarding its theoretical upper bound of predictive accuracy, zero-shot performance, and domain adaptability through fine-tuning. The analysis used two permafrost feature datasets, ice-wedge polygons and retrogressive thaw slumps because (1) these landform features are more challenging to segment than man-made features due to their complicated formation mechanisms, diverse forms, and vague boundaries; (2) their presence and changes are important indicators for Arctic warming and climate change. The results show that although promising, SAM still has room for improvement to support AI-augmented terrain mapping. The spatial and domain generalizability of this finding is further validated using a more general dataset EuroCrops for agricultural field mapping. Finally, we discuss future research directions that strengthen SAM's applicability in challenging geospatial domains. [ABSTRACT FROM AUTHOR]

Rafts are frequently used to design foundations on soft soils to minimize the overall and differential settlements of structures built on them. In many cases, the raft alone can offer sufficient bearing capacity and all that is needed to restrict foundation settlements to a predetermined level with a few widely spaced piles. Granular piles (GPs) can be used due to their several advantages over steel or concrete piles. An annular raft foundation is generally provided for overhead water tanks, chimneys, etc. The provision of granular piles underneath the annular raft foundation not only increases the capacity of the foundation but also minimizes the settlement to an acceptable level. The present study deals with a rigorous analysis of annular raft foundation supported by GPs based on the continuum approach. A new numerical method is developed with geometric considerations for excluding the loaded pile portion from the region of the raft area by considering two distinct zones. This article introduces a novel approach, the annular raft over granular piles, which represents an innovative solution in geotechnical engineering. This innovation has the potential to improve the efficiency and effectiveness of foundation design in various construction projects. The response of annular raft foundation with GPs is evaluated in terms of settlement influence factor (SIF), load shared by granular piles (in %), and normalized shear stress variation along the GP–soil interface. The present study reveals that the presence of the pile influences the stress distribution locally. The stiffness of GP, relative length of GP, relative size of the raft influence the settlement and load sharing of annular raft with GPs. [ABSTRACT FROM AUTHOR]

Corrosion is important in the design, maintenance, and preservation of bridge steel pile foundation systems. It is an inevitable phenomenon when steel is exposed to the environment, as metals tend to return to their lower energy state. While the corrosion rate of steel is predictable for atmospheric exposures, it is highly variable and difficult to predict for steel buried underground because of the high variability of soils. Applying a protective sacrificial layer is a common protection method to prevent corrosion. This study aims to evaluate the efficiency of a galvanized and painted galvanized steel bridge pile for achieving a 100-year service life and to economically compare them for using piles without a coating. To meet this objective, 21 steel coupon samples and nine 30 cm pile samples with galvanized coating, painted-galvanized coating, and no coating were tested in a cyclic corrosion test chamber to investigate the efficiency of each coating. The test was conducted for 600 days simulating a 100-year service life. Results from the experimental test revealed that galvanized and painted-galvanized coating methods show remarkable performance in protecting the piles against corrosion, and both methods can protect the piles from corrosion for 100 years. Further evaluation showed that, while the cost to increase the pile size was determined to be less than the premium for galvanizing or galvanizing and painting the piles for the bridge in this study, a cost–benefit evaluation for each protection measure is suggested, knowing that costs can vary widely depending on specific project requirements, location, market prices, etc. [ABSTRACT FROM AUTHOR]

The horizontal dynamic interaction problems of a floating pile with soil have received little attention from scholars in recent years. This paper first proposed an analytical solution for the dynamic characteristics of the floating pile subjected to horizontal steady-state excitation embedded in soil containing the groundwater table level. Based on Biot's elastodynamic theory, the governing equations of the soil around the pile are obtained. By virtue of the Hankel transform technique and variable separation method, the shaft reactions and base resistances transferred from the soil are calculated and substituted into the dynamic equation of the floating pile derived by the Euler beam model. The dynamic impedance coefficient of the pile head in the frequency domain is obtained by using the transfer matrix method. Comparisons with the previous studies are performed to validate the accuracy of the presented approach. The effects of the thickness of the pile end soil, the slenderness ratio of the pile, the groundwater table level and the relative modulus of pile material on the pile dynamic response are investigated through several numerical analyses. The results show that there is an "active soil thickness" for the horizontal dynamic forced floating piles due to the reflection and refraction of the stand waves. Meanwhile, the effect of the groundwater table level should not be neglected to ensure the safety of pile foundation under service life. [ABSTRACT FROM AUTHOR]

Currently, a standardized design and calculation specification for suction drum foundations has yet to exist in China. The engineering design currently depends mainly on the subjective understanding and engineering experience of the designers, which can be considered somewhat blind and subjective. In this paper, we utilize the offshore wind power project in Yangjiang City, Guangdong Province, as our case study. Building upon domestic and international research results, relevant investigations, design specifications, and engineering applications in related fields, we conduct a systematic study on the design calculation and construction control technology of the suction drum foundation. The document presents the design calculation and inspection of the suction drum foundation. Building on this foundation, we propose a sinking feasibility analysis method and a parameter value method for the suction drum foundation calculation. We also examine the suction drum foundation construction process, examining its control parameters, technology, and standards. Finally, based on the measured data from six four-barrel guided frame platform suction drum foundations that were successfully installed, the proposed design and control method are evaluated, and their effectiveness is verified. The results of this study can provide valuable references for the design and construction of similar suction drum foundation platforms. [ABSTRACT FROM AUTHOR]

To study the applicability of the new geopolymer grouting material for super-long and large-diameter post-grouting bored piles in silty fine sand geology, this paper compares the bearing capacity of two grouting materials, geopolymer and normal Portland cement, and different grouting volume pile side-distributed grouting piles in silty fine sand based on field model tests are analyzed through the diffusion forms of the two materials in silty fine sand through the morphology of the grouted body after excavation. The results show that the ultimate bearing capacities of P0 (ungrouted pile), P1 (8 kg cement grouted pile), P2 (6 kg geopolymer-grouted pile), P3 (8 kg geopolymer-grouted pile) and P4 (10 kg geopolymer-grouted pile) are 5400 N, 8820 N, 9450 N, 11,700 N and 12,600 N, respectively, and that the ultimate bearing capacity of the grouted pile is improved compared with that of the ungrouted pile since, under the same grouting amount, the maximum bearing capacity of the pile using geopolymer grouting is increased by 133% compared with that of the pile with cement grouting. This further verifies the applicability of the geopolymer grouting material for the post-grouting of the pile foundation in silty fine sand. Under the action of the ultimate load, the pile side friction resistance of P1, P2, P3 and P4 is increased by 200%, 218%, 284% and 319% compared with that of P0. In addition, the excavation results show that the geopolymer post-grouting pile forms the ellipsoidal consolidation body at the pile side grouting location, which mainly comprises extrusion diffusion with a small amount of infiltration diffusion, and the cement grouting pile forms a sheet-like consolidation body at the lower grouting location, which primarily comprises split diffusion. This study can provide a reference basis for the theoretical and engineering application of post-grouting piles using geopolymers. [ABSTRACT FROM AUTHOR]

A laboratory model of a single pile embedded in Nanyang expansive soil and subjected to water infiltration is applied in this study to examine the interaction between the expansive soil and pile foundation upon water infiltration. The soil matric suction decreases as a result of the rising soil-water content. The amount of soil ground heave reaches its peak of 10.7 mm after 200 hours of water infiltration. As matric suction decreases, pile shaft friction also declines, which causes more of the load at the pile head to be carried by the pile base resulting in more pile settlements. A new numerical simulation method is provided to simulate this issue by coupling the subsurface flow, soil deformation, and hygroscopic swelling to investigate the expansive soil-pile response upon water infiltration. From the numerical simulation model, hygroscopic strain arises as a result of elevated moisture levels resulting from the entry of water, and due to ground heave and the mobilization of lateral soil swelling, the shear stress at the interface between the soil and the pile gradually increases over time. It reaches its maximum value of 4420 Pa at upper depths around 200 hours after the infiltration. The comparison between the lab model testing data and the numerical model results demonstrates a good level of concurrence. [ABSTRACT FROM AUTHOR]

The design of rock-socketed pile foundations requires careful consideration of critical construction aspects such as the socket roughness and smear for accurately estimating the shaft load capacity. Despite the effect of smear being investigated extensively over the years, previous studies are limited in accurately characterizing the effect of smear on the shaft response. This paper presents a comprehensive investigation on the load-bearing mechanisms of model smeared rock-socketed piles with different smear fabrics (configurations) at the pile-rock interface. These model piles were loaded into synthetic soft rocks while being intermittently subjected to three-dimensional (3D) X-ray computed tomography (CT) imaging. Interpretations from the X-ray CT images were correlated with the pile-head load-displacement behavior to gain insights into the load transfer attributes between the pile, smear, and rock. The various interactions between these components were deduced by monitoring the micromechanics at the pile-rock interface through shaft energy utilization, interface void volume, smear volume, and sand density mapping. Based on the observations, it was inferred that the load transfer between the smear and the rock is primarily dependent on the percentage and position of smear occupancy at the interface. Results indicated that for the partially smeared interfaces, the interface mechanics are a combination of smeared and clean shafts with the residual resistances dependent upon the combined compression of smear and rock debris at the interface. Moreover, it was observed that the continuous presence of smear for more than half area of the leading faces of the pile asperities results in the smeared regions of the pile taking precedence over the unsmeared regions in governing the load-carrying capacity of the shaft. The discussions presented in this study can provide a strong base to further study the smear effect, subsequently aiding in enhancing the existing design guidelines to economically construct piles in soft rock. [ABSTRACT FROM AUTHOR]

Interactions between adjacent piled-raft foundations may induce additional settlement and cause the tilt of the structure. This case study investigates the long-term performance of a large piled-raft foundation system supporting high and heavy alumina solution storage tanks based on field measurements and three-dimensional (3D) numerical simulations. To properly consider the interactions among rafts, piles, and soils; the elastoplastic behavior of clayey and sandy soils; and the consolidation behavior of soil after construction, a 3D finite-difference code was utilized for the numerical modeling. Two undrained mechanical analyses were conducted to simulate the installation of foundations/tanks and the filling of alumina solution into the tanks, while two coupled hydromechanical analyses were performed to model the period between the two undrained stages and the stage after tank filling, respectively. The predictive capability of the numerical model was checked by comparing the simulation results first with single pile load test data and then with in situ settlement measurements at different locations of the piled-raft foundations. The long-term behavior of the piled-raft foundations was further investigated by analyzing various aspects including the axial force variation along the pile at different locations, the time-settlement relation at monitoring locations, the vertical effective stress increment and displacement of soil, and the differential settlement between monitoring locations. Based on the simulations, the tilt of the platform was mainly due to the superposition of additional stresses near the centerline of the two rows of piled-raft foundations. Finally, parametric studies were conducted to investigate the interactions among the piled-raft foundations at different pile length configurations. The results show that by properly increasing the length of the piles near the centerline of the two rows of piled-raft foundations, the differential settlement of the platforms can be mitigated. [ABSTRACT FROM AUTHOR]

In recent years, double-wall steel boxed cofferdams with bottom structures have been applied in the construction of deepwater caps for bridges. However, their mechanical properties are affected by many factors. To elucidate the mechanics influencing such double-wall steel boxed cofferdam configurations, an analytical and computational model was proposed. Through the three-dimensional finite element software midas civil, calculations and analyses were executed on a steel boxed cofferdam design example from the 10# pier pile foundation of the Xinjiang Kalasuke Reservoir's extra-large bridge and its platform construction. The alterations in mechanical states triggered by adjustments to the influential parameters, such as wall plate thickness, water injection height between double walls, and support rod spacing within the double walls of the steel boxed cofferdam, were discussed. Results show that, the optimal wall thickness for this cofferdam variant is between 5 and 6 mm, the controllable water injection height ranges from 3.4 m to 4.5 m, and consistently low-stress states occur across the bottom skeleton, secondary beam, and bottom plate throughout the construction process. The spacing between double-wall horizontal components greatly influences the stress and deformation of the inner and outer wall plates. The obtained conclusions provide a significantly reference value for the design theory and practical application of doublewall steel boxed cofferdam structures. [ABSTRACT FROM AUTHOR]

The selection of construction plans for adverse geological conditions frequently encountered during the construction of bridge pile foundations will have a significant impact on the project's progress, quality, and cost. There is a need for the optimization of multi-attribute decision-making methods, considering the subjectivity in in weight allocation and the practical implementation obstacles. In this study, an evaluation framework for pile foundation construction schemes in karst areas was established. The directed graph and Bellman-Ford algorithm are employed to improve the Analytic Network Process (ANP) in the systematic structure, thereby calculating the subjective weights of various indicators. Simultaneously, based on the concept of dynamic weighting, a multiple linear regression is introduced for analyzing the weights of similar projects, resulting in the derivation of universal weights for the primary indicators within the evaluation system. The combination weights are subsequently determined through the weighted average of the two types of weights. Finally, the comprehensive scores of alternative schemes are computed using the grey-fuzzy evaluation method to enable decision-making in scheme selection. Cloud model, ELECTRE-II, and VIKOR methodologies were utilized for the comparison of results. Combining with a case study of a bridge project in karst development area in southern China, the findings indicate that the improved ANP method possesses practical applicability and yields effective computational results. The introduction of universal weights serves to ameliorate the inherent subjectivity in weight allocation. The pile foundation quality achieved using the optimal construction plan is classified as Class I, which prove the feasibility of the model. [ABSTRACT FROM AUTHOR]

The analytical model for calculating the bearing capacity of a pile, presented in the commentary to STN 73 1002 - Pile Foundations, gives a recommendation to reduce the pile's length in the calculation of the shaft resistance. The recommendation is based on Caquot-Kérisel's theory. Especially in the case of embedded piles, reducing a pile's length in the calculation can cause the shaft friction of the embedded pile to be neglected, and the calculated resistance of the pile is thus significantly lower. The results of instrumented static load tests of embedded piles were analysed. The main aim of the study was to verify the validity of reducing the pile's length in the analytical calculation of the shaft resistance. The results of the static load tests analysed did not show any reduction in the shaft friction on the embedded part of the pile. In the form of a parametric study, the effect of reducing the pile's length in the calculation of shaft friction was analysed for different dimensions of embedded piles. [ABSTRACT FROM AUTHOR]

A number of buildings in the Canadian Arctic communities have failed or showed signs of failure of pile foundations caused by climate-change-induced excessive settlements. Effects of climate change warrant alternative pile types and new installation methods. Installing a pile into frozen soils by the torque method is rare in current practice of the Canadian Arctic. The continuous-flight pile is a new foundation type that is installed by torque. This study is aimed at investigating the axial load transfer of continuous-flight piles in frozen soils under long-term loads. A primary objective is to examine the effects of soil temperature, water content, and soil salinity on the resistance and the failure mode of continuous-flight piles in frozen soils. A series of axial load tests of model continuous-flight piles with a shaft diameter of 89 mm were carried out in the lab. Results show that primary and secondary creeps were observed during the constant load tests. The cylindrical shear mode and individual bearing mode were observed and inferred from the measured data. The adfreeze shear resistance and the individual plate bearing resistance under constant loads were estimated and verified using data from the literature. The adfreeze resistance increased with the applied load, and the plate bearing resistance increased as the normalized pile displacement rate increased. The mobilized adfreeze and plate bearing resistances suggest a potential increased load capacity of the continuous-flight pile compared to conventional smooth piles of similar diameter. [ABSTRACT FROM AUTHOR]

Hurricane and tsunami events can generate extreme water flows in nearshore regions of the United States with catastrophic consequences to coastal structures. Field records have shown that light-frame wood structures exhibit high vulnerability to wave-induced forces due to their light construction characteristics, which feature flexible connections and slender pile foundation systems. Previous research has studied the behavior of these structures under wave action, but most studies used rigid body modeling, which is shown in this study to be insufficient for capturing the force demand on these structures. Using a fluid-structure interaction (FSI) framework, this research investigated the structural and soil flexibility effects in the interaction between elevated light-frame wood structures and water flows. Study variables included the flexibility of timber-to-timber connections, soil type, pile embedment, wavelength, and wave amplitude. The study concluded that structural and soil responses to water flows can introduce strong coupled motions. Neglecting this coupling effect may underestimate the force demand on the light-frame wood structures by more than 40%. Accounting for both structural and soil flexibilities is necessary to accurately quantify the wave force demand of these structures. [ABSTRACT FROM AUTHOR]

This paper presents a mechanical analysis of the foundation of a temporary offshore platform using a temporary embedded eight-leg support structure. The model is simulated using the finite element simulation software MIDAS-3D, with the modified RANS equation and Forchheimer saturated resistance model used to control the fluid. The stress analysis principle of the structure is simplified by the pile group theory. The stability of the eight-legged supporting structure is investigated under different embedding depths, pile diameters, wave periods, and amplitudes of the main piles. The results show that the eight-legged supporting structure can intercept and divert water flow, eliminating the impact of the water flow on the main piles during large waves. Additionally, as the diameter of the structure increases under the same wave conditions, the influence of the base volume and surface curvature gradually increases, deteriorating the stress environment of the main pile and decreasing the supporting effect of the eight-legged support structure. Numerical calculations of the seabed rock foundation of the eight-leg supporting structure show that the shallow pile foundation undergoes significant deformation, while the eight-leg supporting structure is still supported by the dead weight of the main pile. [ABSTRACT FROM AUTHOR]

In order to investigate the sensitivity of weak soil parameters on the deformation of balanced double-row piles, a case study was conducted in a deep foundation pit project in Shenzhen City. A variety of analysis methods, including numerical simulation, field measurements, orthogonal experiments, and theoretical analysis, were employed to analyze the impact of three weak soil parameters on the deformation of balanced double-row piles. The research results showed that the deformation of the front and back rows of piles exhibited overturning deformation, gradually decreasing with depth and reaching the maximum at the pile top due to the constraint effect of the balance platform. The numerical simulation results of horizontal displacements for the front and rear piles were in good agreement with the field measurements, confirming the accuracy and reasonableness of the numerical analysis model and parameter selection. Through a series of orthogonal numerical simulation experiments, it was determined that the cohesive strength (C) of soft layers, such as rockfill and silt, is a key factor, the internal friction angle (φ) is an important influencing factor, and the elastic modulus (E) is a general influencing factor. Theoretical analysis was employed to establish the relationship curve between each parameter and the maximum pile deformation, as well as the sensitivity factors, further verifying the impact of these weak soil parameters. The research findings presented in this paper can provide valuable guidance for geotechnical engineers when selecting geological parameters for similar deep excavation projects. [ABSTRACT FROM AUTHOR]

Deep foundation pit settlement prediction based on machine learning is widely used for ensuring the safety of construction, but previous studies are limited to not fully considering the spatial correlation between monitoring points. This paper proposes a transformer-based deep learning method that considers both the spatial and temporal correlations among excavation monitoring points. The proposed method creates a dataset that collects all excavation monitoring points into a vector to consider all spatial correlations among monitoring points. The deep learning method is based on the transformer, which can handle the temporal correlations and spatial correlations. To verify the model's accuracy, it was compared with an LSTM network and an RNN-LSTM hybrid model that only considers temporal correlations without considering spatial correlations, and quantitatively compared with previous research results. Experimental results show that the proposed method can predict excavation deformations more accurately. The main conclusions are that the spatial correlation and the transformer-based method are significant factors in excavation deformation prediction, leading to more accurate prediction results. [ABSTRACT FROM AUTHOR]

Piled raft foundations are composite foundations that combine piles and raft to support civil engineering structure and to reduce the settlement. The data were obtained from Addis Ababa, Ethiopia. In this study, the effects of raft thickness, number of piles, pile length, spacing of piles, and pile diameter on the response of piled-raft foundations were investigated using the finite element-based program Plaxis 3D for layered soils (medium to very stiff high plastic silty clay and medium to very dense silty sand soil) subjected to uniform vertical loading. The results showed that increasing the thickness of the raft from 0.7 m to 1.7 m reduced the differential settlement by 78.21% when there were 16 piles. However, the maximum settlement also increased by 2.81%. Increasing the number of piles from 4 to 16 reduced the maximum settlement by 22.09% for a pile spacing of 4D. Moreover, increasing the pile length from 9 m to 15 m contributed to a 19.49% reduction in the total settlement for a pile spacing of 5D. Therefore, the current study provides a useful framework for analyzing and designing large piled-raft foundations. [ABSTRACT FROM AUTHOR]

In order to consider the influence of liquid phase and soil anisotropy, the soil around the pile is considered a transversely isotropic saturated porous medium, and a horizontal dynamic model of transversely isotropic saturated soil-pile is established. Based on Beor's saturated porous medium theory and the constitutive equation of transversely isotropic media, the horizontal dynamic control equation of transversely isotropic saturated soil is obtained without considering the vertical displacement. The horizontal vibration of transversely isotropic soil layers was solved using the potential function and separation of the variable method, and the horizontal and radial displacements of the solid soil skeleton of transversely isotropic saturated soil were obtained. The horizontal force of transversely isotropic saturated soil on a single pile was also obtained. On this basis, the horizontal dynamic equation of a single pile in transversely isotropic saturated soil was established, and the horizontal vibration of the pile foundation was solved using the initial parameter method, and the horizontal dynamic impedance of a single pile in transversely isotropic saturated soil is obtained. The influence of soil anisotropy parameter, liquid-solid coupling coefficient, diameter-length ratio, and modulus ratio on the horizontal dynamic impedance of a single pile in transversely isotropic saturated soil was analyzed through numerical examples. The analysis results show that the anisotropy parameters δ 1 , diameter-length ratio r 0 / H , and modulus ratio E p / C 66 have a significant impact on the horizontal dynamic impedance of pile foundation in transversely isotropic saturated soil, and the influence of anisotropy on the horizontal vibration of pile foundation should not be ignored. The influence of the liquid-solid coupling coefficient on the horizontal dynamic impedance factor is related to frequency to a certain extent. [ABSTRACT FROM AUTHOR]

The high-strain dynamic test method possesses the attributes of speed, efficiency, and environmentally-friendly, low-carbon characteristics. To study the reliability of the high-strain dynamic test method in detecting the bearing capacity of pile foundation in permafrost regions, 4 test piles, each with a length of 15 m and a diameter of 1.0 m, were poured based on the actual bridge construction project in the permafrost region of Daxing'an Mountains in China. Based on the temperature data between the piles and soil, the refreezing state of the pile foundation was comprehensively judged. Subsequently, the static method was employed to assess the friction resistance values and single pile bearing capacity of each soil layer on the pile side under different freezing states before and after the pile foundation refreezing. Building upon these findings, the restrictive parameters for soil elastic limit q (i) , soil resistance R U (i) and other parameters in the pile-soil model of high-strain dynamic test method are clarified. The test and analysis results indicate that under the condition that the ground temperature of frozen soil is about − 1.9 °C, the pile-soil refreezing takes about 120 days, and the pile-soil refreezing is a slow process; In CAPWAPC calculation program, after the values of soil parameters were constrained by the results of static-load test, the calculated curve is in satisfactory agreement with the measured curve, and the parameters of the pile-soil model are reliable, which can be used for the rapid detection of the ultimate bearing capacity of piles in permafrost regions; In the process of pile-soil refreezing, the change of temperature field affects the freezing strength between pile and soil, the process of pile-soil refreezing is positively correlated with the increase of pile foundation bearing capacity. [ABSTRACT FROM AUTHOR]

Tracked vehicles are widely deployed for heavy lifting and transportation on inaccessible terrains such as swamps, bogs, and peatlands. The stability of a tracked vehicle is traditionally assessed only under uniaxial loading conditions and the impact of combined loading from different directions is ignored. This makes the conventional design framework somewhat unreliable. The failure envelope approach has been widely employed to assess the load-carrying capacity of shallow foundations. However, the failure envelopes available in public domain mainly focused on single isolated foundations, ignoring the interference effect between the tracks due to the rigid connection of the vehicle. This paper aims to develop an integrated framework to assess the stability of a tracked vehicle on a soft soil under fully three-dimensional loading conditions. The finite element method is adopted to simulate the soil–vehicle interactions, with the tracks idealised as two shallow foundations in parallel. The stability of the foundation system is described in terms of failure envelopes considering various track configurations and load combinations. Failure envelopes are represented by expressions and ultimately integrated into a multiple-nested function to determine the overall stability factor. The framework is demonstrated by a case study of designing a tracked vehicle under combined loading conditions. [ABSTRACT FROM AUTHOR]

The movement of the ground and the redistribution of stress caused by shield tunneling result in deformations and changes in internal forces in bridge pile foundations, which, in turn, affect the safety of pile superstructure. A numerical computational model based on the modified Mohr–Coulomb (MMC) criterion was proposed to analyze the effects of shield tunneling on the stability of the pile foundations of existing bridges during the early, middle, and late stages of shield tunnel construction. A 3D numerical model of the shield tunnel and bridge pile foundation was constructed using the finite element software Midas GTSNX. The ground movements and deformation patterns of pile foundations were analyzed throughout the entire shield tunneling process beneath existing bridge pile foundations. Results demonstrate that utilizing the elastic-plastic constitutive model founded on the MMC criterion is more effective for illustrating the surface settlement pattern induced by shield tunnel construction. Bridge piles are continuously deforming during the construction of a shield tunnel. The deformation of a bridge pile is maximized when a shield tunnel reaches the foundation of the pile. The deformation of bridge pile foundations remains stable after passage. The deformation and bending moments of bridge pile foundations decrease with an increase in distance from the tunnel. The influence on bridge pile foundations is reduced with an increase in distance from the shield tunnel. This study provides a good reference for the construction quality control and safety assessment of similar tunnel projects. [ABSTRACT FROM AUTHOR]

In this investigation, deformations of a deep foundation pit in hard rock strata, respectively, under delayed and in-time supporting schemes of one-layer transverse reinforced concrete bracings at the top of the foundation pit, one-layer steel bracings at a depth of 8 m, and one-layer prestressed anchorages at a depth of 22.5 m during excavation were characterized according to lateral deformations of the foundation pit, settlements of the surrounding ground, and axial forces of the steel bracings according to numerical calculations and on-site monitoring. Numerical calculation results showed that the maximum lateral deformations of the foundation pit and settlements of the surrounding ground were, respectively, 10.34 mm and 8.49 mm at an excavation depth of 31 m, which were obviously larger than those under in-time supporting. Meanwhile, under delayed supporting conditions, lateral deformations of the foundation pit and settlements of the surrounding ground were far less than the allowed values, respectively, being 0.3% and 0.15% of the excavation depth, required in the Chinese standard of GB50007-2011, indicating that the foundation pit under delayed supporting conditions had good stability. Therefore, when excavating deep foundation pits in hard rock strata, proper delayed supporting schemes could be considered so that strengths of the surrounding hard rocks could be utilized to the fullest, and at the same time, more spaces for excavation could be freed up, and construction duration and construction costs could thus be lowered. [ABSTRACT FROM AUTHOR]

In this paper, a general power form of head-loss (pressure-drop) equation and the concept of shear velocity were used to study non-Darcy filtration through coarse granular materials. Using new laboratory data, the validity of four widely-used power form pressure-drop equations were evaluated. The results indicated that for the lower size of grain diameter (d ≤ 8.7 mm) the Wilkins (in: Proceedings of the 2nd Australia-New Zealand Conference on Soil Mechanics and Foundation Engineering, Christchurch, 1956) method has predicted satisfactorily the hydraulic gradient, while for the higher size of grain diameter (d ≥ 15.6 mm), the Stephenson (Rockfill in Hydraulic Engineering, Elsevier Science Publishers B.V., Amsterdam, 1979) method predicted acceptably the pressure gradient. The results also indicated that the best estimation for the Izbash coefficient a is the Wilkins method. Finally, new correlations for friction factor, shear velocity and Reynolds number as well as new threshold limits for Darcy, partially-turbulent, and fully-turbulent flow regimes are presented and discussed. [ABSTRACT FROM AUTHOR]

In view of the complexity of the pile foundation underpinning structure system and the stringent requirements of the construction process, this paper briefly describes the necessity of introducing epoxy resin reinforcing adhesive of planting rebar in the design of pile foundation underpinning beam structure to improve the mechanical properties of the reinforced beam new and old concrete joint surfaces and proposes a new type of pile foundation replacement beam system construction method by "chiseling + prestressed reinforcement + epoxy resin reinforcing adhesive". This paper uses an actual pile foundation underpinning project of an urban overpass as a prototype, designs and creates a model structure with a similarity ratio of 1/6, and performs repeated progressive static loading tests to study the load carrying capacity, displacement change, and other properties of the strengthened replacement structure, as well as analyses and distorts the overall working performance and failure mode of them. On this basis, the prototype structure's finite element analysis model was built, and the finite element analysis results were compared with the test results to obtain the mechanical properties and deformation characters of the actual pile foundation underpinning structure system corresponding to the actual underpinning beam load. This paper's study can lay the theoretical and experimental foundation for the smooth development of similar projects. [ABSTRACT FROM AUTHOR]

Negative skin friction caused by ground settlement is an important consideration for deep foundations in limit states design. However, there are inconsistencies in the methodology whereby negative skin friction and associated drag force are considered in assessing the geotechnical capacity or geotechnical ultimate limit state (ULS) in various design codes. This includes two current North American bridge design codes, the Canadian Highway Bridge Design Code, and AASHTO LRFD Bridge Design Specifications. A test pile program was developed to observe effects of ground settlement on pile settlement, capacity, and drag force. Two instrumented steel H-piles were driven through a compressible clay layer to a hard end-bearing stratum, subjected to ground settlement by constructing a 1.5 m high embankment, followed by static load testing. A load-transfer model was calibrated from the test pile program observations. Test results and the calibrated model were used to compare geotechnical ULS requirements of the two bridge design codes. It is demonstrated that drag force did not detrimentally impact pile capacity. The results showed that for conditions of the test pile program, assessing the geotechnical ULS can be more conservative when adhering to the current AASHTO LRFD Bridge Design Specifications than the Canadian Highway Bridge Design Code. [ABSTRACT FROM AUTHOR]

Reinforced earth retaining walls are being utilized more frequently in civil infrastructure projects as an alternate design structure to typical reinforced concrete walls and other structures for supporting backfill. The objective of the present study is to model and analyze a 2-dimensional Segmental Precast Concrete Panel (SPCP) wall using the 2-dimensional finite-element tool PLAXIS and analyze the behaviour of the wall concerning the effect of reinforcement type and surcharge loads. The present work also includes the investigations of the effects of reinforcement type and surcharge loads, as well as the influence of different supporting systems on the deformations and ground-surface settlements of the SPCP wall. Ribbed steel reinforcements, Polyethylene Terephthalate (PET) geogrids and Density Polyethylene (HDPE) geogrids are used to evaluate the wall deformations for reinforcement types. For ribbed-steel reinforcement, ground settlements and wall deformations are 14% and 25% less compared to those of PET and HDPE geogrid reinforcements, respectively. With the increase in surcharge on the backfill soil, wall deformations and surface-ground settlements are increased significantly by 150%. To decrease the deformations of walls resting on soft soil, pile foundations and aggregate piers are considered as supporting solutions. In the case of reinforced blocks with pile foundation as supporting systems, the wall deformations and settlement are 60% lesser than for aggregate pier supporting systems. [ABSTRACT FROM AUTHOR]

Advancing tunnel boring machine (TBM) during tunnel construction induces a surface settlement, affecting adjacent buildings and facilities. A three-dimensional finite-element model (Plaxis 3D) was used to simulate and analyze this process. A comparison between the numerical model and field measurements of the Greater Cairo Metro (Line 3) was made to validate the obtained results. A sensitivity analysis was conducted to determine how changes in some parameters, such as constitutive models, pile position relative to the tunnel axis and pile spacing, affect the results of the finite-element model. Three constitutive models: hardening soil small (HSS), hardening soil (HS) and the Mohr-Coulomb (MC) models, were used to evaluate the effect of the constitutive models on the results. From the numerical analysis, it is clear that the numerical results are in good agreement with field measurements. The results of the HSS model are more realistic and closer to field measurements than those of the HS and MC models. Furthermore, the effect of the tunnel construction on the settlement of adjacent piles is virtually null at a distance of 2 D (where D is the tunnel diameter). Finally, increasing the pile spacing decreases the effect of tunnel excavation on adjacent pile foundations. [ABSTRACT FROM AUTHOR]

On 6 February 2023, East Anatolia was devastated by two major earthquakes resulting in hundreds of thousands of collapses and tens of thousands of human casualties. This paper investigates the factors related to building properties and earthquake environmental effects (EEEs) that contributed to the building damage grade and distribution in southeastern Turkey. In regards to the building construction properties, the loose enforcement of the building code, the random urban planning solutions and the poor construction standards are the main construction deficiencies that led to one of the largest disasters in Turkey's recent history. Regarding geological factors, the triggering of primary and secondary EEEs largely shaped the grade and distribution of damage. Where coseismic surface ruptures intersected with the built environment, heavy to very heavy structural damage was observed. This was evident in many cases along the ruptured segments of the East Anatolian Fault Zone (EAFZ). Liquefaction observed close to waterbodies caused damage typical of building foundation load-bearing capacity loss. The earthquake-triggered landslides affected mainly mountainous and semi-mountainous settlements characterized with pre-earthquake high related susceptibility. The high susceptibility to generation of EEEs was extensively confirmed in many cases resulting in extensive damage. The provided information highlights the importance of such studies for hazard mitigation and disaster risk reduction. [ABSTRACT FROM AUTHOR]