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Tolerably mobile subsea foundations are designed to slide on the seabed to accommodate flowline thermal expansion and contraction, and are a potential alternative to conventional (fixed) foundations. During the periodic sliding events that occur during operation, soil berms form at the extremities of the foundation footprint. The size of the berm increases throughout the life-cycle of the foundation, leading to increasing peak sliding resistance. This may hinder mobility of the foundation and overstress the pipeline connections that the foundation is designed to support. Equally, the berms may be relied on to reduce sliding and thus minimize settlement of the foundation, which can also overstress pipeline connections. This paper analyses the mechanism leading to berm accumulation and its mobilisation, also addressing periodic remoulding and reconsolidation of the sediment in the berm. A framework is proposed to predict the accumulation of soil berms and the resulting peak sliding resistance, and is validated by eight centrifuge model tests performed on a kaolin clay and a calcareous silt. [ABSTRACT FROM AUTHOR]

Based on the perspective of flight technology and flight safety, the unsaturated clayey foundation soil of a high plateau airport in the mountainous area of southwest China is taken as the research object, and the calculation method of the composite modulus of CFG pile composite foundation with the soil between the piles as the unsaturated soil is established according to the relevant characteristics of unsaturated soil, and the calculation method of the composite foundation's settlement is carried out on the basis of this method. At the same time, Plaxis finite element analysis software is used to model the actual project and numerically analyze the settlement characteristics of the composite foundation. Finally, the calculation results of the two methods are compared and studied with the actual settlement monitoring values on site. The study shows that: 1) the theoretical analysis method is able to consider the effects of pile length, pile modulus, and matrix suction in unsaturated soil of rigid piles on the composite modulus, which is more in line with the reality than the conventional composite modulus method that does not consider the unsaturated nature of the soil between the piles; 2) the resultant values computed by the theoretical and numerical analysis methods recommended in this paper are both smaller than those measured at the site but the difference is within the range of 10%, so that in the actual plateau of the High Plains airports can choose the two analysis methods recommended in this paper to conduct related research. [ABSTRACT FROM AUTHOR]

In order to ensure flight safety, the requirement of foundation settlement of high-plateau airport is stricter than that of airport in plain area. In order to monitor the abnormal state of runway foundation in the process of use of a high-plateau airport and prevent and resolve the major risk of foundation settlement to flight safety. It takes a high-plateau airport in the southwest mountain area as an example, selecting two representative A and B sections for analysis. It takes the first 60 days' monitoring data as training samples, which shows nonlinear characteristics. The Long and Short Term Memory neural network (LSTM) prediction model and BP neural network model are constructed to predict the trend of foundation settlement after construction. In the process of building the LSTM model, the minimum root-mean-square error of test samples was selected as the fitness function, and the parameters of the LSTM model were modified by Genetic Algorithm (GA). And then the modified LSTM prediction model based on the early settlement of the foundation was constructed. The results shows that the modified LSTM model and BP model constructed in this paper are generally consistent with the field measured values in the prediction of airport foundation settlement of high-plateau, but the modified LSTM model is more sensitive to the abrupt change of data and has a more stable trend than the BP model. The predicted values of the modified LSTM model are all greater than those of the BP model, and the predicted values of the modified LSTM model are closer to the monitored values in the field than the predicted values of the BP model, and the relative error between the predicted values and the monitored values is less than 3%. The research can provide a reliable theoretical reference for the design, construction, operation management and later maintenance of high-plateau airport. [ABSTRACT FROM AUTHOR]

Rockfall frequently occurs in the mountainous areas and threatens structures such as settlement areas, transportation lines, and agricultural field. The empirical approaches for rockfall mapping have been an attractive research topic in rock mechanics in the recent years, because producing rockfall maps of large areas by using the deterministic and the probabilistic analysis seems difficult due to the necessity of numerous inputs. The cone propagation approach is preferred as a practical tool particularly in the regional scale. The digital elevation model (DEM) of a region prone to rockfall is used for determination of possible propagation zones based on a simple geometric rule known as the energy line angle (reach angle). As a new term, ELAmax_stop was defined to represent the energy line angle that extends to the border of the propagation zone as the maximum run-out distance that is obtained from application of the cone approach to all points (pixels) in source area. The angle denoted as α refers to the threshold slope angle of the steep areas utilized to identify potential source areas by using DEM. Conceptually, the fallen rock blocks within a rockfall-prone region stop within the cone propagation zone, which is bounded by the energy line angles α and ELAmax_stop. While the value of α is susceptible to the resolution of DEM, ELAmax_stop, which exhibits a wide angle range as documented in the literature, is controlled by rock block features together with slope surface properties of the propagation zone. Due to the variability of ELAmax_stop and α depending on the studied region and the resolution of the DEM, the boundary value of the energy line angles between different susceptibility classes need to be adjusted by considering α and ELAmax_stop. By adopting the cone propagation approach to enable adjustable use of energy line angles for rockfall susceptibility mapping, a series of graphical presentations was prepared. These graphical presentations allowed for the prediction of energy line angles corresponding to various rockfall susceptibility classes including very low, low, medium, high, and very high. In addition to the graphical presentations, a series of practical equations were derived for the same purpose. In the final part of the study, a new rating system, namely the run-out distance rating (RDR), was introduced for the preliminary determination of ELAmax_stop. Due to the empirical structure of the methodology, the suggested supportive approach to the practitioners for determining ELAmax_stop should be considered as an initial step that opens to improvement. The proposed methodology in this study was implemented in the regions of Kargabedir Hill and Sivrihisar residential areas in Turkey to prepare rockfall susceptibility maps. [ABSTRACT FROM AUTHOR]

A polyethylene pipe reinforced by winding steel wires (PSP) consists of steel wires and high- density Polyethylene (HDPE). Due to its unique structure and combination of material, the PSP possesses excellent mechanical properties, and it has been widely used in many fields as a buried pipe. Foundation settlement is an evitable loading, and strength failure of buried PSP sometimes occurs due to the foundation settlement. In this paper, numerical investigation of failure behavior of buried PSP was conducted. Firstly, groups of uniaxial tensile tests were carried out to acquire the rate-dependent constitutive equation of the HDPE. Secondly, finite element model of PSP embedded in soil subject to foundation settlement was established. Steel wires are represented by truss elements, and HDPE pipes were modeled with solid elements. The steel wires are built in a spiral structure similar to the real steel-wire mesh of PSP. The effect of the nonlinear material property of components were considered in the model, as the tensile curves were input into the model. The PSP was buried in soil, and foundation settlement was applied on a part of the soil's top surface as the displacement boundary condition. Due to the great ductility of HDPE, the steel wires broke prior to the HDPE, so the maximum stress of steel wires was used as the failure criterion of PSP. Once the maximum stress of steel wires exceeds the ultimate strength, PSP was considered to have failed. Based on this model, the stress distribution along PSP was investigated with various internal pressure and settlement displacement. The combined influence of the internal pressure and foundation settlement on PSP failure behavior was analyzed, and the location where failure most possibly occurred was determined under different loading conditions. Furthermore, the influence of different structural parameters of PSP and soil was discussed. [ABSTRACT FROM AUTHOR]

The combination of permeable and impermeable columns is commonly employed to enhance the stability of natural ground and expedite the consolidation process while effectively reducing foundation settlement. This study presents a comprehensive investigation of the consolidation characteristics of unsaturated composite foundations (USCF) using various methods. Firstly, a mathematical model is developed under the assumption of equal strain, considering depth‐dependent initial stress. To obtain more generalized analytical solutions for excess pore pressures and foundation settlement, separation of variables, Laplace transformation, and inversion Laplace transformation are employed. Secondly, the accuracy of the proposed analytical solutions is validated by comparing them with two specific cases reported in the existing literature, achieved by reducing the compression modulus of columns. Lastly, a series of parameters are investigated to examine the consolidation characteristics of USCF considering depth‐dependent initial stress. The results demonstrate that the final settlement of the foundation will be overestimated while the variation of vertical stress along the depth is neglected. Furthermore, adjusting the values of area replacement ratios proves to be more effective and straightforward than modifying the compression modulus of columns in the reinforcement treatment of USCF. [ABSTRACT FROM AUTHOR]

Air-booster vacuum preloading (AVP) without sand blanket and surcharge vacuum preloading (SVP) methods were used to treat two adjacent areas in a foundation reinforcement project on Donghai Island, Zhanjiang City, Guangdong Province, China. In this study, engineering characteristics of the AVP foundation were obtained through analyzing monitoring data. Results showed that the AVP method obtained superior foundation consolidation results compared to SVP method. This study proposed a new simplified mechanical model for AVP, with a single PVD (prefabricated vertical drain) centered and the air-booster pipes symmetrically distributed around the PVD, applied equivalent air-booster pressure to the drainage boundary. Furthermore, this study established a mathematical analytical model for predicting consolidation settlement based on the proposed simplified model. By comparing the theoretical settlement value with the measured value, this paper verifies the rationality of the analytical solution. Finally, this study analyzed the effects of well resistance, smearing effect, compression index, and permeability index ratio on consolidation characteristics. Land reclamation projects will generate a large amount of dredged ultrasoft soil foundation. The AVP method can achieve superior foundation treatment effects by injecting gas into soil mass through air-booster pipes. The results of this case study demonstrate that the AVP method has substantial advantages compared to the conventional vacuum preloading method. The AVP method can increase foundation settlement, shorten the time for foundation treatment construction, and improve the foundation reinforcement effect. In addition, the AVP method can alleviate PVD clogging and maintain soil permeability, while simultaneously avoiding the excessive use of dredging sand. Therefore, the AVP method can lead to potential economic benefits and protect the natural environment, and it is a method worth considering. Moreover, the mathematical model for predicting consolidation settlement of the AVP method was proposed based on new mechanical assumptions, which can be applied as a reference for settlement prediction in relevant engineering, and the rationality has been verified through comparison with measured settlement results. [ABSTRACT FROM AUTHOR]

In many settlement prediction methods, the creep settlement of shallow foundations on sand is either disregarded or accounted for using time correction factors that lack a reliable basis. These existing settlement correction factors for creep have mainly been derived from a restricted number of long-term settlement measurements and do not consider the influence of factors such as the load level, rate of load application and properties of the soil below the foundation. In this study, a newly proposed one-dimensional elasto-viscoplastic macro-element was used to investigate the factors influencing the time-dependent behaviour of shallow foundations on sand. The safety factor of the foundation, the creep characteristics of the soils and the duration of load application were found to have important effects on the post-construction settlement development. The simulation results were used to develop an enhanced settlement correction factor for creep, which takes into account the identified factors. The improved settlement correction factor was found to be comparable to existing ones when the safety factor of the foundation is 3. The effectiveness of the proposed settlement correction factor is demonstrated using creep settlement measurements from one field footing test and two case histories. [ABSTRACT FROM AUTHOR]

One of the greatest challenges faced when using gravity settling is achieving efficient particle removal and retention rates under high inflow rates. This paper proposes a new method for enhancing sedimentation and protecting the settled particle. This is accomplished by placing one layer of the virtual bed above the real bed to divide the water body into hydraulically different upper and lower regions. The normal structure of the newly-proposed virtual bed is a flat plate with many small perforations. When the water flows along the top surface of the virtual bed, it creates two effects: (1) it isolates and protects water in the area below the virtual bed from being disturbed by the fast and turbulent flows above, which enhances sedimentation of the particles in the lower region and protects the sediment which could be eroded; and (2) the vertical vortex generated by the surficial flows passing over the openings helps the nearby suspended particles to enter the quiescent water region below. To assess the performance of the newly-proposed virtual bed, a rectangular settling tank was used to conduct comparison tests of particle removal with three particle size ranges, four inflow rates, five virtual bed structural designs, and multiple experimental conditions. The results clearly showed that, compared with a traditional settling tank (without the virtual bed), the addition of the proposed settling structure notably enhanced the particle settling rate by 10%–15% for the particles tested and experimental conditions assessed. The virtual bed method easily can be applied to various water treatment devices and facilities to enhance the suspended particle removal efficiencies in treatments of storm runoff, wastewater, and many other kinds of water without the need for chemical additions or energy-intensive processes. This paper proposes and tested an innovative method for increasing the removal of suspended particles using a virtual bed. A virtual bed is composed of a plate with numerous holes through it suspended above particle-settling facilities. It enhances particle settling by providing a less disturbed region for settling particles, protecting already-settled particles, and encouraging the suspended particles to move toward the real bed. Laboratory tests in a rectangular tank with different particle sizes and flow rates showed that the virtual bed effectively improved particle removal rates. Various possible virtual bed structure designs are proposed and were examined. The best-performing virtual bed was identified, and possible reasons for its performance were discussed based on hydraulics and physics principles. Experiments with different tank configurations and virtual bed position arrangements were conducted, and based on the experimental results, general suggestions for using the virtual bed in practice more effectively are given. In principle, the proposed virtual bed can be applied to any particle-separation facilities. [ABSTRACT FROM AUTHOR]

During a deep excavation project, monitoring the structural health of the adjacent buildings is crucial to ensure safety. Therefore, this study proposes a novel probabilistic deep reinforcement learning (PDRL) framework to optimize the monitoring plan to minimize the cost and excavation‐induced risk. First, a Bayesian‐bi‐directional general regression neural network is built as a probabilistic model to describe the relationship between the ground settlement of the foundation pit and the safety state of the adjacent building, along with the actions in a dynamic manner. Subsequently, a double deep Q‐network method, which can capture the realistic features of the excavation management problem, is trained to form a closed decision loop for continuous learning of monitoring strategies. Finally, the proposed PDRL approach is applied to a real‐world deep excavation case in No. 14 Shanghai Metro. This approach can estimate the time‐variant probability of damage occurrence and maintenance actions and update the state of the adjacent building. According to the strategy proposed via PDRL, monitoring of the adjacent buildings begins in the middle stage rather than on the first day of the excavation project if there is full confidence in the quality of the monitoring data. When the uncertainty level of data rises, the starting day might shift to an earlier date. It is worth noting that the proposed PDRL method is adequately robust to address the uncertainties embedded in the environment and model, thus contributing to optimizing the monitoring plan for achieving cost‐effectiveness and risk mitigation. [ABSTRACT FROM AUTHOR]

Analytical approaches to determine the long-term settlement of shallow foundations subjected to dynamic cyclic loading with a large number of cycles (millions) are presented. The approaches use the high-cycle accumulation (HCA) model to calculate the permanent strain caused by the cyclic loading and are conceptionally similar to conventional settlement analyses. The incorporation of a threshold strain amplitude, below which no accumulation of deformations occurs, in the HCA model is discussed. It is demonstrated that the simple analytical approach, which does not require numerical calculations, gives results very similar to more complex finite-element simulations. [ABSTRACT FROM AUTHOR]

Interference effects of two adjacent foundations include changing failure mechanism, load settlement, and stress distribution behavior; this can result damages such as differential settlement, tilting, cracking, reduction of serviceability, and even failure. To address these issues, the present study aims to assess the effect of the number of new adjacent building stories on settlement and the tilt of the existing building. The study evaluates the interference effects of two adjacent foundations on sand and fill by finite-element Plaxis 3D in two groups. The first numerical modeling group is conducted in a small scale and compared with laboratory tests that are performed on a 1 g chamber with a height and diameter of 1 m, thickness of 0.01 m, revealing a similar settlement and tilting pattern. The second group is modeled two closely circular footings in full scale. The results showed that the induced settlement increases as the number of stories increases, from 7.5 to 23.5 mm for sand and 25.6 to 38.2 mm for fill, respectively, when the applied load increases from 40 to 100 kN/m2. Moreover, in the fill soil, the settlement of the foundation's center was, on average, 167% more than that of sand, with an increase in the number of stories from 4 to 6, and this difference reduced to about 77% in higher stories. Finally, three real cases include "Guilan Residential Building, Grain Silos and Athens Buildings" are evaluated by numerical modeling and induced complications assessed. [ABSTRACT FROM AUTHOR]

Tunnel excavation leads to ground settlement and may cause existing buildings to suffer damage due to excessive deformation. Researchers proposed and studied several protective measures to mitigate the risk of damage to above-ground structures. Concrete and steel diaphragm walls effectively reduce the foundation settlement and are considered successful in protecting nearby structures. Compressing compressible material has advantages as the cost and environmental issues are considered. This study aims to investigate the effectiveness of geofoam buffer in reducing surface movement by conducting two-dimensional numerical analyses. Following verification of finite-element analysis through instrumental readings of the Isfahan subway case, numerical models were developed to determine barrier characteristics' effectiveness on the ground deformation. Analysis results show that the pre-installation of the geofoam diaphragm adjacent to the buried tunnel significantly mitigates the ground surface settlement; however, some adverse effects may be developed in the zone behind the Expanded Polystyrene (EPS) diaphragm wall. [ABSTRACT FROM AUTHOR]

Summary: The mechanical characteristics of the setback super‐tall structure are complex, and the design is difficult. In the actual analysis and design process, the relevant influencing factors should be fully considered. In this paper, the fine construction simulation analysis of the super‐tall structure is carried out. Based on the shrinkage test of concrete members, the CEB‐FIP 90 shrinkage model is modified in terms of the parameters of cross‐section shape and size. The modified model is used to calculate the shrinkage strain of concrete, and the influence of uneven settlement of foundation and seasonal temperature on the structure is considered in the construction simulation analysis. The influence proportion of each non‐load effect on the horizontal displacement, vertical displacement, and internal force of key components is obtained. The refined construction analysis results are compared with the field monitoring data, and the data are in good agreement. [ABSTRACT FROM AUTHOR]

The intricate geological conditions of reservoir banks render them highly susceptible to destabilization and damage from fluctuations in water levels. The study area, the Cheyipin section of the Huangdeng Hydroelectric Station, is characterized by numerous ancient landslides of varying scales and ages. In June 2019, during the reservoir filling process of the Huangdeng Hydroelectric Station, a large-scale reactivation of ancient landslides occurred in this area, posing severe threats to riverside infrastructure and human safety, including ground cracking, house cracking, foundation settlement, and road collapse. The reactivation mechanism of ancient landslides at reservoir banks is highly complex due to fluid dynamics. This study conducted field investigations in the Cheyipin landslide area, monitored surface and subsurface deformations using GNSS and inclinometers, and analyzed the distribution characteristics, destruction features, and reactivation mechanisms of the landslides through correlation analysis and numerical calculations. The results indicate that the instability pattern of the slopes manifests as traction-type sliding failure. The slopes do not slide along the ancient sliding surface but along a newly formed arcuate sliding surface, with the direct impact area mainly concentrated near the waterline. The stability of the slopes in this project is closely related to the reservoir water level. It can be assumed that the lowering of the reservoir water level triggered the reactivation of the ancient landslides in the Cheyipin section, while the influence of rainfall can be ignored. To prevent the reactivation of ancient landslides, attention should be focused on the changes in reservoir water level, avoiding rapid adjustments in water level during the initial lowering and final raising of the water level. [ABSTRACT FROM AUTHOR]

Soil liquefaction is a destructive geotechnical hazard during earthquakes which causes not only ground settlement and foundation bearing capacity reduction but also lateral spreading of the ground. Lateral spreading can be harmful to embedded structures such as piles and hence may dominate the seismic design of piles. In this study, the behavior of piles subjected to liquefaction-induced lateral spreading was characterized by investigating a pile damage case during the 1964 Niigata, Japan earthquake. Firstly, both flow displacement and flow pressure approaches for modelling of lateral spreading and the beam on nonlinear Winkler foundation method for modeling of pile-soil interaction were adopted to numerically simulate the reality and an existing centrifuge test of the case. Then, a 1 g scaled physical model test was performed through compulsorily displacing a model ground which was liquefied by upward seepage to approximate the action of lateral spreading on the pile. The obtained results were compared with those from the field observations and existing study concerning the deformation, moment and soil reaction distribution, and damage mode of the pile. It was shown that the flow displacement approach better approximated the investigated case in which the pile penetration depth into the non-liquefied base layer was relatively small. The analyzed moment and soil reaction distribution along the pile were closer to those observed in the tests, leading to flexural damage of the pile near the interface of liquefied and non-liquefied layers just like the reality. [ABSTRACT FROM AUTHOR]

"Shifting transnational bonding in Indian diaspora" is a book edited by Ruben Gowricharn that focuses on the experiences of the Indian diaspora around the world. The book explores themes such as the reinforcement process of the Indian diaspora, emerging tendencies in Indian transnationalism, and the socio-economic factors contributing to the bonding among these communities. It is divided into three sections: Global and local encounters, Glocalisation, and Regional Transnationalism. The chapters in each section delve into specific topics related to the lived experiences of immigrants and the complexities of their sense of belonging to their homeland or hostland. The book offers engaging insights into the field of diaspora studies, although it could have provided more elaboration on the acculturation context in the host society and problematized the overarching conceptualization of the diasporic trajectory of immigrant groups. [Extracted from the article]

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]

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]

While the main focus of numerous engineering-geological investigations is to determine load-bearing capacity and settlement in engineering structures, this article aims to point at the specificity of sewer system engineering-geological investigations, which focuses on workability of soils and rocks. The study deals with workability class assessment of seven different sewer system localities. The significance of this research lies in the mutual comparison of workability class assessment of these seven localities in terms of two different workability standards. Each of the standards represents an independent model of assessment and classification of workability. The first standard (CSN 73 1001) classifies soils and rocks into seven workability classes, while the second (EN ISO 14688) comprises only three workability classes. Each of the approaches has its advantages and disadvantages. In comparison to the first one, the second standard permits faster and easier classification of rocks, but may be less fair to investors or developers when considering the real engineering-geological conditions and costs of implementation. Rocks were newly classified into three (easy, medium and difficult) categories of earthwork realization difficulty. In the study, 33 layers were classified in the category of easy realization of earthworks, 8 layers in the category of a medium degree of earthwork realization difficulty, and two layers in the category of a difficult realization of earthworks. [ABSTRACT FROM AUTHOR]

The settlement deformation of the retaining wall, slope top and the soil behind it is an important index for the safety of foundation pit engineering. By analyzing the settlement amount and settlement rate of the structure, scientific guidance can be provided for engineering construction. The average settlement rate and vertical cumulative settlement of the foundation pit group on the south bank of Dalian Bay Subsea Tunnel for two years (from August 29, 2020 to May 27, 2022) were obtained by small baseline set time series Interferometric Radar Technology (SBAS -InSAR). The results show that the maximum settlement in this area is 75.3 mm. The monitoring results were verified using measured leveling data. The verification results show that is feasible to apply this technology to foundation pit monitoring. [ABSTRACT FROM AUTHOR]

Ground fissure is the most common geological catastrophe phenomenon in Xi'an, posing a major security threat to the currently developing urban cloud rail transit system. In this paper, a 3D-FEM calculation model is established to study the influence of the intersection angles between the hidden ground fissure and the cloud rail on the deformation and failure characteristics of the structure. The findings indicate that the pile foundation is under tension in the main deformation area of the hanging wall of the ground fissure, and the negative friction zone (NFZ) appears below the neutral point (buried depth 18 m for intersection angle 30°). The pile foundation is under compression in the footwall, and the pressure it bears is less than the tensile force sustained by the hanging wall pile, and the NFZ is above the middle point. The NFZ of the pile foundation in the hanging wall and footwall increases as the intersection angle decreases. The pile foundation mainly undergoes vertical settlement, and the horizontal displacement is relatively small. The 3D movement of the pile foundation results in settlement and inclination of the superstructure of the cloud rail simply supported beam bridge, such as the pier and track beam. Therefore, the cloud rail bridge should span the ground fissure at a large angle as far as possible, and 3D adjustable support should be adopted to adjust the offset of the track beam caused by the ground fissure. [ABSTRACT FROM AUTHOR]

This study shows the application of the deep learning (DL) algorithm in the inversion of the crucial constitutive model parameters directly referring to the surface settlement monitoring data. Three parameter inversion models (BiLSTM, CNN1D, and ConvLSTM) based on DL algorithm are used for a comparative study. The datasets for training and testing are synthetic data that we calculated by importing the independently designed Python script into the finite element (FE) software ABAQUS. The Mohr–Coulomb (MC) model and the Modified Cam-Clay (MCC) model are used in the numerical model. The generalization abilities of the inversion models are tested using the monitoring settlement of the new airport in Xiamen, China. The main results show that: (i) the three-parameter inversion models based on DL can accurately identify the soil parameters that have a significant influence on the settlement calculation, and (ii) in terms of training time and prediction accuracy, the inversion model based on CNN1D has a better comprehensive performance than ConvLSTM and BiLSTM. The good consistency between the settlement calculated by the parameters retrieved from the DL model and the monitoring values shows that it has great potential to use DL as a meta-model for the calculation of the foundation settlement and the prediction of future development. [ABSTRACT FROM AUTHOR]

The novelty of this paper is to propose exact three-dimensional analytical solutions to the half infinite thermo-elastic body pressed by a rigid cylindrical structure for the first time, in which uniform heat flux flowing from rigid structure into the half infinite body is considered. Using recent general solutions expressed by four harmonic functions and extending potential theory method to consider heat effect, the governing integral equations are first derived. Then, the equations are analytically solved and displacement, stress, and temperature field components expressed by elementary functions are obtained. To validate the presented solutions, the correctness of the solutions is exactly examined, and normal contact displacement and stress without heat effect are compared with those in literatures. Furthermore, a numerical example which is the stainless steel thermo-elastic body pressed by a displacement restrictor is studied. Displacement, stress, and temperature distributions are analyzed, and the influence of heat flux on the pressed depth is also discussed in detail. The analytical solutions presented in this paper are rather important in engineering practice and can provide a basis for indentation analysis, displacement restrictor design, foundation settlement calculation, and so on. [ABSTRACT FROM AUTHOR]

To study the instability mechanism of the slope of the widened highway roadbed during rainfall, a rainfall simulation device was developed for geotechnical centrifugal model testing. Settlement and widening tests for the old roadbed, and settlement and simulation rain tests for the widened roadbed were performed in sequence. During the test, the settling process of the old and the new roadbeds and the instability process of the embankment slope by rainfall were observed by the settling monitoring device installed on the centrifuge manipulator system. The test results showed that the major consolidation of the old roadbed was completed in the first year of operation; after the roadbed was widened, the new settlement of the old roadbed was much smaller than the new settlement of the widened roadbed, resulting in the differential settlement between the new and old roadbeds. Longitudinal cracks formed by the differential settlement on the road surface provided infiltration channels for rainwater. After rainfall, the rainwater first infiltrates downward at the foot of the slope and expands the vertical joints of the loess to form vertical infiltration channels, causing settlement at the foot of the slope. After that, the rainwater infiltrated laterally into the interior of the roadbed and beyond the slope toe, increasing further settlement. The settlement area expanded continuously, eventually causing the roadbed slope to become unstable. According to the research results, the key to preventing rainfall damage to the subgrade was to protect the slope foot, block the rainfall infiltration channel, and reduce the settlement of the foundation. [ABSTRACT FROM AUTHOR]

Earth platforms supported by rigid columns provide an effective solution for embankments founded on thick deposits of soft soils. Nevertheless, the failure mechanisms and associated soil–structure interactions remain inadequately comprehended, particularly for structures such as columns with caps or ground beams. Recent studies have reported sporadic incidents of basal instability in rigid column–supported embankments over soft soil. To gain further insight into this issue, this study investigated the foundation settlement, failure mode of rigid columns, and ground stability under staged embankment construction by centrifuge model tests. Different ground improvement schemes (head conditions) are compared, including columns, capped columns, and columned ground beams, along with natural ground as a base model. Test results show that the potential slip surfaces for embankments on soft ground are almost circular in shape, with or without capped column support. Rigid columns exhibit different failure modes across the improved domain: compression failure under the crest, bending failure under the shoulders, and tensile/bending failures near the toe. Under critical conditions, the columns near the toe collapse first, followed by the adjacent columns beneath the slope and center of the embankment. In contrast, the column failure sequence is unclear for the beam scenario. Capped columns were found to reduce the foundation displacement significantly. Given equivalent area coverage ratios, columned beams demonstrate greater efficacy in controlling ground deformation than capped columns. The interconnecting beams form a strong foundation that mitigates overstressing of subsoil, thus reducing differential and final settlements. Finally, the stability of the ground reinforced with rigid columns under embankment loading is discussed, taking into account the fracturing of columns and the function of caps and ground beams. [ABSTRACT FROM AUTHOR]

While design methods of deep foundations are mainly developed for homogenous soil deposits, the presence of highly cemented layers could lead to underestimation of resistance and overestimation of settlement of pile foundations. This study presents a novel approach using competent caliche layers bonded to the top and bottom of a continuous flight auger (CFA) pile as a new composite foundation system named caliche stiffened pile (CSP). The key objective is to optimize the required pile length in a cost-effective approach without ameliorating soil properties. Settlements of the CSP foundation for a high-rise building were monitored and full-scale tests were conducted to measure piles' capacity. Finite element back analyses were performed to avoid adverse effect of sample disturbance in settlement calculations. A back calculation of a test fill embankment was performed to determine soil stiffness parameters by simulating an unscheduled imposed load to the structure. Impacts of the CSP on controlling the settlement of pile foundation and optimizing the required pile length are investigated using finite element analysis and a parametric study. The proposed CSP foundation can reduce the CFA pile settlement significantly in the presence of caliche layers with thickness equal or greater than a pile diameter at CFA pile head and toe, where the CSP is located. [ABSTRACT FROM AUTHOR]

Uneven settlement phenomenon is very easy to occur in the sandy pulverized ground stratum, the underground pipe corridor longitudinal and transverse stiffness difference is obvious, so that it is easy to crack and deformation due to uneven settlement in this type of stratum. This paper carries out research on uneven settlement and cracking and deformation of Qihe tube corridor, analyzes the reasons leading to uneven settlement and the factors affecting the deformation and cracking of the tube corridor, and provides guidance for foundation treatment and tube corridor repair and mixing and reinforcement. It was found that the concrete structure of the corridor itself had exposed reinforcement, pockmarks and holes, and that cracks on the structure of the corridor sprouted and expanded from these defects. Defects and damages on the concrete structure of the pipeline corridor are contributing factors to the deformation and cracking of the members, and the uneven settlement of the foundation is the main initiating factor for the cracking and deformation. The analysis of the numerical simulation results of similar underground pipeline corridors is carried out, and it is found that the simulation results are consistent with the deformation characteristics of the Qihe pipeline corridor, which further supports the conclusions of this paper. The main stratigraphic factors contributing to the inhomogeneous settlement were found to be the water-rich and loose bodies in the lower part of the strata, as revealed by the physical means and the experimental verification boreholes. Localized hydraulic effects such as pumping further accelerate the uneven settlement of the foundation. [ABSTRACT FROM AUTHOR]

Induced partial saturation (IPS) is a new foundation treatment method for mitigating soil liquefaction using biogas. A series of laboratory tests were performed to demonstrate the influencing factors of IPS using Pseudomonas stutzeri biogas. On the basis of the optimal biogas production conditions, the intervention effect of Pseudomonas stutzeri biogas on the foundation deformation under buildings was investigated based on shaking table tests. The test results showed that the best carbon source in the denitrification process of Pseudomonas stutzeri biogas is sodium citrate. The most effective initial value of optical density-based concentration was 0.1. The carbon–nitrogen ratio (C/N) of the bacterium suspension was used as the index to control the saturation. The degree of saturation reduction showed a good linear correlation with the C/N. The optimum temperature of this method was between 20 °C and 30 °C. The most suitable pH value was between 7 and 9. The environmental factors had minimal influence on the degree of saturation reduction but had a significant effect on the average rate of gas generation and the period of initial stagnation. After Pseudomonas stutzeri biogas desaturation, the settlement of the building was greatly reduced. The settlement of saturation of 92.5% sand foundation reached 17.1 mm, and the 85% saturation was only 10.6 mm. These results provide a good foundation for the feasibility of utilizing Pseudomonas stutzeri biogas mitigation of the liquefaction hazard of sand. [ABSTRACT FROM AUTHOR]

The effect of vertical vibrational loads on the bearing capacity of a foundation resting on salt-encrusted flat soil improved by cement addition was experimentally examined by conducting a physical model. The vibration foundation model resting on the finite dimensions of cemented sabkha was first subjected to incremental vertical monotonic loads to evaluate the bearing capacity for different subsoil conditions; the bearing capacity was calculated from the load–settlement curves. The cemented sabkha overlies the saturated sabkha soil. The influence of the vertical vibrational load for each increment in the vertical monotonic load on the settlement was studied, and a modified load–settlement curve was introduced. For a foundation with no large deformation or liquefaction due to vibrational loads, the vibrational loads insignificantly influence the bearing capacity of the foundation. With increasing frequency, the initial stiffness decreases, resulting in an increase in the settlement. The influence of the cement content and thickness of cemented sabkha on decreasing the foundation's settlement decrease with increasing monotonic loads and operating frequency. [ABSTRACT FROM AUTHOR]

Roadbed construction typically employs layered and staged filling, characterized by a periodic feature of 'layered filling—filling interval'. The load and settlement histories established during staged construction offer crucial insights into long-term deformation under filling loads. However, models often rely solely on post-construction settlement data, neglecting the rich filling data. To accurately predict composite foundation ground (CFG) settlement, an LSTM–Transformer deep learning model is used. Five factors from the 'fill height–time–foundation settlement' curve are extracted as input variables. The first-layer LSTM model's gate units capture long-term dependencies, while the second-layer Transformer model's self-attention mechanism focuses on key features, efficiently and accurately predicting ground settlement. The model is trained and analyzed based on the newly constructed Changsha–Zhuzhou–Xiangtan intercity railway section CSLLXZQ-1, which has a CFG pile composite foundation. The research shows that the proposed LSTM–Transformer model for the settlement prediction of composite foundations has an average absolute error, mean absolute percentage error, and root mean square error of 0.224, 0.563%, and 0.274, respectively. Compared to SVM, LSTM, and Transformer neural network models, it demonstrates higher prediction accuracy, indicating better reliability and practicality. This can provide a new approach and method for the settlement prediction of newly constructed CFG composite foundations. [ABSTRACT FROM AUTHOR]

This paper presents the performance of three types of small-scale shell foundations (pyramidal frustum, semi-cylindrical and prismatic shell) of the same plan area on different states of sand provided with or without reinforcement. To understand the effect of reinforcement and its dependency on the vertical embedment depth, two cases were considered, i.e. reinforcement at a depth equal to 0.5 B (B=width of foundation) and another case at a depth equal to B. Bearing capacity for different shell foundations models and settlement behaviour were studied based on the load settlement curves and compared with that of conventional flat foundation model. The experimental results show that shell models perform better than the flat foundation model in terms of bearing capacity and settlement resistance on the different states of sand with or without reinforcement. The relationship of ultimate load with the angle of internal friction was found. Reinforcement embedded at 0.5B depth was found to be better than provided at B depth in all the states of sand. It is also noticed that the bearing capacity ratio is lower for the sand reinforced at a depth of B than that of 0.5B, showing the dependency on reinforcement embedment depth. [ABSTRACT FROM AUTHOR]

It is important to predict the future behavior of historic buildings to avoid potential problems. Wat Khao Sukim Pagoda is situated on a hill slope and has different types of foundations. These foundations include both shallow and pile foundations representing different stages of construction and having different loadings. Although the structure meets the design criteria for the current loading, in the future overloading may occur. Therefore, an analysis of additional loading was undertaken using the 3D finite element method (FEM). In particular, the effects of differential settlement and its mitigation were investigated. Changes in the groundwater level were simulated after major rain events and compared to dry conditions. Overall, the concept of staged construction (preloading) is a useful technique to minimize the risk of differential settlement associated with different types of foundations. In addition, the current results showed that the average differential settlement value at each stage was lower than in previous work. Furthermore, the new model reduced the differential settlement value by more than 50%. These results showed that the concept of preloading can better solve the differential settlement problem in this type of construction. The PLAXIS 3D model showed that the groundwater level increase did not affect Pagoda settlement, indicating that the Pagoda was stable and could withstand a large load without undergoing any major structural deformations and that it was suitable structurally for a variety of applications, even in wet conditions. [ABSTRACT FROM AUTHOR]

Foundation settlement prediction is significant to the reuse and management of the reclaimed land from the sea by dykes where composite stratum of many strata with different physical and mechanical properties is encountered. Toward the foundation settlement analysis of reclaimed land in the Yellow Sea composite stratum in eastern China, a weighted-combination model is proposed in this paper combining the hyperbolic model, exponential curve model, and Asaoka model. First, the weight coefficient of the weighted-combination model is calculated by the reciprocal square method of average absolute error (MAE). Second, the settlement prediction results of different models are evaluated by the absolute error, MAE, root-mean-square error, and mean absolute percentage error. Finally, the settlement mechanism of reclaimed foundations in a composite stratum is analyzed from the point of view of the multistratum coupling, and the adaptability of different models to the settlement prediction of reclaimed foundations in a composite stratum is discussed. The results show that the predicted settlement duration curves of the weighted-combined model are in good agreement with the measured settlement duration curves, and the prediction performance is better than that of the hyperbolic model, exponential curve model, and Asaoka model. The MAE of the weighted-combination model is 75.7% lower than that of the exponential curve model, 90.2% lower than that of the hyperbolic model, and 70% lower than that of the Asaoka model. This model provides a new way to predict the settlement of reclaimed foundations in a similar composite stratum. [ABSTRACT FROM AUTHOR]

The issue skirted foundations, which are typically made of steel or concrete, feature a skirt beneath the periphery. These foundations are primarily used in offshore structures. They offer the advantage of reducing material costs and installation time. Unlike shallow foundations, skirted foundations transfer the load to a deeper level, thereby enhancing the foundation's bearing capacity and minimizing settlement. This study focuses on the performance of square-skirted foundations under static and seismic compressive loading by numerical and physical modeling methods. It specifically assesses the impact of skirt length on the bearing capacity and settlement of the foundation, considering a soil density of 40% under vertical load conditions. The analysis takes into account different skirt length-to-width ratios (L/B) of 0.0 (surface), 0.5, 1.0, and 1.5. The results indicate that the inclusion of skirts enhances the bearing capacity and settlement behavior of surface foundations on sand, with improvements increasing as skirt depth increases. These findings suggest that the implementation of skirts is an effective technique for reducing both displacements and acceleration in vertical directions, enhancing foundation resistance, and significantly improving the structure's response to earthquake loading. The experimental results align with numerical modeling, validating its use for large-scale designs. However, further investigations using full-scale tests are needed to generalize these results for real-world applications. [ABSTRACT FROM AUTHOR]

Shake table experiments are conducted to assess the potential of the polymer injection technique as a liquefaction countermeasure. A large 2.9 m high (10 ft) laminar soil container on a 3.9×1.85 m (13×6 ft) shake table is employed. Mitigation of liquefaction-induced settlement for a shallow foundation is explored. In a series of two shake table experiments, the system response is studied first without (baseline) and subsequently with polymer injected into the liquefiable stratum. Each test is densely instrumented to provide insights into the dynamic response of the soil and foundation system. Furthermore, cone penetration tests (CPTs) are performed pre- and postinjection to assess the extent of soil improvement. Strong base excitation is imparted by the shake table, resulting in liquefaction and excessive foundation settlement in the original baseline test. In the second test, with the polymer injection countermeasure, a significant reduction is observed in the tendency for liquefaction and the resulting foundation settlement. After this test, careful excavation provided additional insights into the polymer's configuration within the deposit, increasing overall soil relative density, confinement and creating solidified paths for the shallow foundation load toward the lower, more competent stratum. As such, these mechanisms have the potential to allow for: (1) an increase in soil resistance to liquefaction, and (2) a significant reduction in settlement of overlying shallow foundations. [ABSTRACT FROM AUTHOR]

It is inevitable to cross buildings in the process of urban shield construction. Now, relying on the soft ground above and hard ground below the shield between Taoyuan Road Station and Shengjin tower station section of Nanchang rail transit line 4 project, the software PLAXIS 3D was used to analyze the influence of the construction sequence of the tunnel shield on the buildings and the ground settlement. At the same time, the influence of different construction sequence, different shield speed, tunnel face pressure and the distance between the shield tunnel excavation face and the building pile foundation on the settlement of the building pile foundation was analyzed. The results showed that the construction of the right line first and then the left line has the least impact on the building compared with other construction sequences; The simulation results of the optimal scheme were completely consistent with the actual monitoring results; The faster the shield speed was, the less the consolidation time of soil was, and the smaller the impact on buildings was; The greater the tunnel face pressure, the greater the disturbance to the soil and the greater the impact on the building; When the shield tunnel excavation face was farther away from the building, the impact on the building was smaller. When the excavation face was more than 7m away from the vertical distance of the building pile end, the impact of the horizontal distance between the tunnel and the pile foundation on the surface settlement was very small. The conclusion had certain guiding significance for the subway shield construction in Nanchang area. [ABSTRACT FROM AUTHOR]

Modifying the loess foundation effectively solved the deformation and settlement of the building foundation and improved its stability. However, burnt rock-solid waste was often used as filling material and light aggregate, while there were few studies on the engineering mechanical properties of modified soil. This paper proposed a method of burnt rock solid waste-modified loess. Therefore, we conducted compression-consolidation and direct shear tests on burnt rock solid waste-modified loess under different burnt rock contents to explore its improved loess's deformation and strength characteristics. Then, we used an SEM to investigate the modified loess's micro-structures under different burnt rock contents. The results showed that as the burnt rock-solid waste particle content continued to increase, the void ratio and compressibility coefficient of the samples with different ranges of burnt rock-solid waste particles gradually decreased with rising vertical pressure, while the compressive modulus increased first, then reduced and then increased with the increase of vertical pressure; the shear strength indexes all showed an increasing trend with the increased content of burnt rock-solid waste particles; when the content of burnt rock-solid waste particles was 50%, the compressibility of mixed soil was the lowest, the shear strength was the largest, and the compaction effect and shear resistance were the best. However, when the content of burnt rock particles was 10–20%, the shear strength of the soil improved significantly within the content range. The mechanism of burnt rock-solid waste to enhance the strength of the loess structure was mainly to reduce the porosity and average area of soil, significantly improve the strength and stability of mixed soil particles, and thus significantly improve the mechanical properties of soil. The results of this research will provide technical support for safe engineering construction and geological disaster prevention and control in loess areas. [ABSTRACT FROM AUTHOR]

The complexity of the cohesive soil structure necessitates settlement modeling beneath shallow foundations. The goal of this research is to use recently discovered machine learning techniques called the hybridized radial basis function neural network (RBFNN) with sine cosine algorithm (SCA) and firefly algorithm (FFA) to detect settlement (Sm) of shallow foundations. The purpose of using optimization methods was to find the optimal value for the primary attributes of the model under investigation. With R2 values of at least 0.9422 for the learning series and 0.9271 for the assessment series, both the produced SCA - RBFNN and FFA - RBFNN correctly replicated the Sm, which indicates a considerable degree of efficacy and even a reasonable match between reported and modeled Sm. In comparison to FFA - RBFNN and ANFIS - PSO, the SCA - RBFNN is believed to be the more correct method, with the values of R2, RMSE and MAE was 0.9422, 7.2255 mm and 5.1257 mm, which is superior than ANFIS - PSO and FFA - RBFNN. The SCA - RBFNN could surpass FFA one by 25% for the learning component and 14.2% for the test data, according to the values of PI index. Ultimately, it is apparent that the RBFNN combined with SCA could score higher than the FFA and even the ANFIS - PSO, which is the proposed system in the Sm forecasting model, after assessing the reliability and considering the assumptions. [ABSTRACT FROM AUTHOR]

The Millennium Tower is a 58-story reinforced concrete building that was constructed in San Francisco, California, between 2005 and 2009. The Tower is founded on an embedded pile-supported mat with pile tips bearing in dense marine deposits that overlie an overconsolidated marine clay layer known locally as Old Bay clay. This clay layer experienced stress increases from Tower self-weight and from multiple episodes of dewatering between 2006 and 2018 at the Tower site and neighboring sites, including one that was sustained for 6 years. Settlements of the Tower foundation have been measured since 2006, and lateral deflections of the Tower have been inferred and measured since 2009. The data show that during multiple episodes of "loading" (from stress increase or dewatering), settlements initially accelerated and then gradually slowed over time, as expected from consolidation principles. Similarly, lateral deflections (from foundation tilt) (1) accelerated following foundation construction activities at adjacent sites (dewatering and excavation); and (2) oriented toward adjacent excavations, which at various times occurred to the project south, north, east, and west of the Tower site. An objective of this paper is to describe this case history, including the geotechnical site conditions and results of a monitoring program that tracked foundation settlements, Tower tilt, groundwater levels at the Tower site, and ground inclinations over time. We also evaluate soil deformation mechanisms that likely produced the movements. We find that settlement amounts and time variations are well captured by one-dimensional and three-dimensional analyses of volume change in Old Bay clay and other foundation soils from primary consolidation and secondary compression, provided that time variations of stress increase and groundwater level are accounted for. Three-dimensional analyses also capture time variations of lateral deflections, which were caused by volume change and shear deformations in foundation soils, the latter having been affected by unloading from adjacent excavations. [ABSTRACT FROM AUTHOR]

Dynamic loading causes (1) a substantial change in the strength and deformation parameters of sandy soil and (2) excessive viscoplastic deformation. The goal of this study is to create a new analytical solution to the problem of the settlement of (1) the foundation that is the source of dynamic loading, and (2) a nearby foundation, taking into account the rheological properties of sandy soil subjected to vibration, given that these rheological properties depend on shear stresses. The proposed solution allows the progress of deformation over time to be described. The present paper states and provides an analytical solution for the problem of evaluating the settlement of a single foundation that transmits static and dynamic harmonic pressure to the base. The authors also analyze the settlement of another foundation located at some distance from the transmitting foundation. The second foundation transmits static pressure to the base. The dependence of the viscosity coefficient on the shear stress intensity and vibration intensity, as well as the vibrocreep decay over time, are based on the exponential and homographic dependencies previously identified by two of the authors (A.Z. Ter-Martirosyan and E.S. Sobolev). The solution to the problem is obtained by numerical integration in the Mathcad program of an analytical expression for nonlinear viscoplastic deformations. As a result of the research, the authors have found that the dynamic viscoplastic component makes the greatest contribution to foundation settlement. The settlement of the transmitting foundation increases along with increasing static and dynamic pressure transmitted to the base. The settlement of the nearby foundation increases when the pressure increases under the foundation, but it reduces when static pressure from the transmitting foundation, the depth of the foundation, and the distance between the foundations increase. General analytical dependencies obtained by the authors comply with the results of laboratory and field experiments performed by other researchers. These dependencies can be used to predict the settlement of foundations in whose unsaturated sandy bases mechanical vibrations propagate. [ABSTRACT FROM AUTHOR]