bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanical mechanism of soft soil foundation improved by geosynthetic-reinforced pile-supported technology based on field experiment
Authors: Liu H Y , Qian J S , Ling J M , Wang J H , Lin H Y 
Published: May 2024

Abstract
Geosynthetic-reinforced pile-supported (GRPS) technology is an effective method for improving soft soil foundations. Conducting field tests is crucial for accurately assessing the mechanical behavior of GRPS technology. Based on the fourth expansion project at Pudong Airport, field tests were conducted to investigate the effects of GRPS technology on soft-foundation treatment. Specifically, the tests examined the changes in the pile and soil settlement, pore water pressure, and pile and soil stress. The results showed that the settlement of the GRPS foundation mainly occurred during the loading period, accounting for approximately 65% of the total foundation settlement. Increasing the pile modulus and reducing the pile spacing decreased the total foundation settlement. The filling load was mainly transferred to the piles through the soil arching effect, resulting in a large excess pore water pressure in the soil layer near the pile tip. In addition, when the filling height was low, the load transfer relied predominantly on the tensile membrane effect of the geogrid, which was more pronounced near the piles. However, as the filling height increased, the soil arching effect surpassed the tensile membrane effect and played a key role in load transfer.
Performance of incineration bottom ash amended marine soft clay stabilized by cement in seawater
Authors: Sun Xinlei , Zhi Yeon Ting Matthew , Yi Yaolin 
Published: May 2024

Abstract
Incineration serves as an effective waste management method driven by its ability to reduce mass and volume of municipal solid waste. However, this process generates incineration bottom ash (IBA), which is commonly disposed of in landfills in many countries, especially when dealing with fine IBA. To address this issue, recycling fine IBA for soft marine clay (MC) stabilization is a sustainable option compared to landfilling. Previous studies revealed that aggregate-like and weak hydration properties of fine IBA may increase the strength and decrease compressibility of MC. Nevertheless, when using IBA-MC in land reclamation or coastal protection, the performance may deteriorate, particularly in the presence of seawater. Therefore, this study employed chemical stabilization method combined with ordinary Portland cement (OPC), to solidify/stabilize IBA-MC (OPC-IBA-MC). The aim was to improve the performance of IBA-MC in seawater. The appearance, water content, strength, mineralogy, and microstructure of IBA-MC and OPC-IBA-MC soaked in seawater were investigated. The results showed that the strength of OPC-IBA-MC (4075 kPa) cured in air for three months was significantly higher than that of IBA-MC (983 kPa). Nevertheless, after soaking in seawater, OPC-IBA-MC was dismantled, rendering its strength untestable. The mineralogy and microstructure of OPC-IBA-MC revealed that the formation and growth of ettringite caused instability in OPC-IBA-MC in seawater.
Model tests on red clay foundation reinforced by coir geotextiles
Authors: Li Liang-yong , Chen Jia-cheng , Yang Lin , Zhang Qing-song , Cao Wei-qiang , Cheng Yan-wen 
Published: May 2024

Abstract
Geosynthetics slowly degrade in soil, which may cause environmental problems in the future. Natural coir fibers are green, environmental-friendly, renewable, and have broad application prospects. Coir geotextiles were used to reinforce red clay foundations. The effects of the reinforcement length and depth, first-layer reinforcement depth, and reinforcement-layer spacing on the deformation and bearing capacity of the foundations were studied via load tests. The distribution law of the earth pressure along the depth was also analyzed. The results showed that when the reinforcement length was 1B, the anchorage length of the reinforcement was insufficient, and the reinforcement effect was unclear. As the reinforcement length increased, the anchoring length of the reinforcement increased, and bearing capacity of the foundation significantly increased. However, when the reinforcement length exceeded 3B, the force of the anchorage segment was fully exerted, slightly increasing the bearing capacity of the foundation. The optimal reinforcement length was determined as 3B. The bearing capacity of the foundation increased as the reinforcement depth increased and the buried depth of the first reinforcement layer and spacing of the reinforcement decreased. The optimal reinforcement depth, buried depth of the first reinforcement layer, and reinforcement spacing were 2B, 0.25B, and 0.25B, respectively.
Basic Mechanical Properties of Unit Cell-based Stiffened Deep Mixed Column
Authors: Zhang Yusen , Xu Yan , Li Guangyao , Ye Guanbao , Zhang Zhen 
Published: May 2024

Abstract
As a composite column, stiffened deep mixed (SDM) column is formed by inserting a precast concrete core pile into the center of a deep mixed (DM) column. When SDM columns are used to support embankments over soft soil, they would be failed by shearing, compression, tension, and bending. This study conducted a series of laboratory tests to investigate the basic mechanical properties of a unit cell of SDM column, including uniaxial compression, direct shear and tension tests. The results reveal that the impact on improvement was minimal at a core ratio of 9.8%, subsequently followed by a substantial rise. In addition, the radial compression strength reached the maximum at a core ratio of 25%, and the shear strength approached to a constant value when the core element ratio exceeded 25%. Increasing the area ratio resulted in the change of failure modes of core element. Finally, a relationship among the different strength was discussed.
Soil-cement columns for high-rise buildings: design–testing–construction–monitoring: A case study of green solution in Vietnam
Authors: Dao D H , Ngoc P V , Nam H P , Puppalla A , Han J 
Published: May 2024

Abstract
Soil cement columns (SCCs) are commonly used to reinforce soft ground to support roads and railway embankments, or to withstand horizontal pressure for deep excavations. This study presents another application of SCCs as load-bearing foundations for high-rise building projects. SCCs with a diameter of 800 mm, length of 10 m, cement content of 350 kg/m3, and an unconfined compressive strength (UCS) of 3.6 MPa were applied. In this study, five single columns and one group constituting two columns were constructed, and core drilling and axial static load tests were conducted. The test results indicated that the SCC could achieve a load of 1,650 kN for a single pile and 3,300 kN for the group constituting two columns. In total, 1,123 columns were designed and constructed for this project. Compared with conventional reinforced concrete pile methods, a project using SCC could save 30 construction days and 20% of the total cost. Moreover, SCC can be considered a green and environmentally friendly foundation solution because it does not use concrete or steel materials and does not produce waste soil.
Building responses to soil removal, dewatering, and artificial recharge during deep excavation in water-rich sandy strata
Authors: Liu J C , Hu S L , Tan Y , Chao H 
Published: May 2024

Abstract
In water-rich sandy strata, deep excavations necessitate dewatering within the excavation site, leading to significant groundwater drawdowns and surface subsidence behind walls, which can result in severe damage to adjacent buildings. Nonetheless, the individual impacts of soil removal and dewatering in such permeable sandy formations on building responses remain ambiguous,with scant reported protective experience in literature. This study introduces a validated three-dimensional fluid-solid coupling finite-element model to simulate the construction of an 18-19.8 m deep subway station in Nantong, China. Artificial recharge was applied to mitigate adverse effects on nearby buildings caused by drainage. The investigation explores the separate effects of soil removal, dewatering, and water recharging on the settlements of buildings with three different foundations (natural, raft, and piled footings). Additionally, the influence of post-recharging groundwater levels on building responses was scrutinized. The present findings indicate that discharging confined aquifers significantly contributes to building settlements, while artificial recharge can substantially reverse the deformations in buildings, especially those with natural and raft foundations. As excavation depth and the bearing capacity of the building foundation increase, the relative impact of soil removal on building settlements grows, whereas the influence of dewatering diminishes. Compared to enhancing foundation-bearing capacity, artificial recharge emerges as a more cost-effective strategy to safeguard pre-existing buildings near deep excavations in water-rich sandy strata, provided the post-recharging groundwater levels achieve a certain threshold.
A case study of the response of support structure and stratum deformation caused by deep foundation pit excavation in soft area
Authors: Zhu Q X , Qin H L , Song B W , Wang L , Lü X L 
Published: May 2024

Abstract
Investigating the spatial distribution and evolution patterns of deformations during foundation pit excavation is crucial for safeguarding the surrounding environment. This study focuses on a deep excavation case in Nanjing and discusses the strata deformation and the response of the retaining structure through the excavation phase, informed by on-site monitoring data. A three-dimensional finite element model of the excavation was developed, with comparisons between predicted values and on-site deformation monitoring data underscoring the accuracy of the numerical simulation results. This analysis delved into the deformation spatial distribution within the retaining structure and ground surface settlement throughout the excavation. Moreover, the three-dimensional deformation patterns of the diaphragm wall at various excavation depths were scrutinized, mapping the evolution pattern and spatial distribution of ground surface settlement around the foundation pit across different excavation stages. The findings reveal a pronounced spatial effect in both the diaphragm wall deformation and ground movements behind the wall, with the greatest deformation manifesting near the symmetric plane of the excavation center and markedly less deformation near the excavation corners. Furthermore, the deformation scope broadens with increasing excavation depth. These research outcomes aim to furnish a substantive reference for practical engineering implementations.
Geomechanical impact on subway tunnels beneath open-cut tunnel excavation pits under long-distance overlapping conditions
Authors: Zhou B , Zhao C 
Published: May 2024

Abstract
In urban locales characterized by high population density, tunneling activities frequently entail extensive spatial overlap with pre-existing subway infrastructure. Thus, the geomechanical impact of open-cut excavation pits on subjacent subway tunnels is highly significant. Drawing upon the empirical data from the Tunnel Project of Erqi Square in Zhengzhou City, China, a suite of three-dimensional numerical models was formulated to scrutinize the interplay of three salient variables—excavation depth, excavation width, and vertical clearance between subway tunnels and excavation pit floors—on subway tunnel deformation. The findings elucidate that: (1) the predominant deformation mode of subway tunnels is vertical uplift, with the maximum vertical displacement exhibiting an almost linear correlation with both excavation depth and vertical clearance, yet diminishing in rate with incremental excavation width; (2) among the variables, excavation depth exerts the most pronounced impact on vertical deformation, followed by vertical clearance, whereas excavation width plays a comparatively marginal role; (3) Predictive model for estimating maximum vertical displacement in the silty clay strata of Zhengzhou City was derived through multiple linear regression analysis, and its efficacy was corroborated through juxtaposition with extant measured data, thereby validating its applicability for preliminary prediction of the maximum vertical displacement of subway tunnels in long-distance excavation above the subway tunnels.
Prediction of the undrained base heave and post uplift in braced excavation of a typical subway station in thick soft clay
Authors: Gao Y B , Li Y J 
Published: May 2024

Abstract
Construction of a typical subway station usually involves a narrow long excavation with a width of approximately 20 m. An undrained base heave is a common problem in deep excavation areas with soft clay, which may induce considerable post uplift and damage the safety of the retaining system. Post uplift involves complex interactions between soil, pile post foundation, and supported struts, and an accurate prediction of post uplift is challenging. This paper aimed to establish a practical method for predicting the base heave and post uplift in the construction of typical subway stations in areas with thick soft clay. Series soil–water coupled finite element method (FEM) analysis was conducted to investigate the characteristics of the base heave with different soil properties and wall stiffnesses. The results showed that the calculated base heave can be fitted by a normalized function, regardless of large variations in soil properties and wall design parameters. The normalized function was then applied to a soil–post–strut interaction analysis model to predict the post uplift at different excavation depths. The application of the proposed method to a real subway station project showed that the predicted results were in good agreement with the field observations.
Study on new micro-pile structure for reinforcement of shallow foundation
Authors: ma Yibao , Li Zixi , Zhang Ga , Wang Gang 
Published: May 2024

Abstract
Micropiles are widely adopted for reinforcing shallow foundations. A new type of topping micropile structure was proposed in this study. A certain length of the expansion section was added to the upper part of the micropile, which not only retained the cylindrical section of the micropile but also enhanced the limiting effect on the lateral displacement of the soil near the shallow foundation. A comparative centrifugal model test of the new micropile and an ordinary micropile was conducted by applying a vertical load on the foundation. Under the test conditions in this study, the bearing capacity of the new micropile reinforcement foundation increased by approximately 50% compared to that of an ordinary micropile.The new miniature piles significantly reduced the settlement of the foundation. The reinforcement effect of the new micropiles on a shallow foundation was more pronounced than that of an ordinary pile given that the new micropiles possessed numerous limitations on the lateral deformation of the soil base under the shallow foundation.
Performance of unequal piled raft under vertical loading in cohesionless medium
Authors: Kumar Malviya Dinesh , Samanta Manojit 
Published: May 2024

Abstract
The performance of piled rafts with unequal pile lengths in cohesionless soil under vertical loading was investigated in the present study through experimental and numerical analysis. A pattern function is used to define the pile length arrangement. The motivation for considering such a function is to ensure that the varying pile lengths follow a suitable geometric pattern, and it does not obstruct the construction practice in field applications. The piles at different locations within the raft were equipped with strain gauges to observe the strain distribution along their lengths during the static load test. Load sharing was evaluated by placing an earth pressure cell beneath the raft. A three-dimensional finite element analysis was used to simulate the experimental results aimed at assessing the load settlement and load-sharing responses. A comparison was conducted to verify the reliability of the tests. Subsequently, a detailed parametric study was conducted in accordance with different pattern functions, pile spacing, and pile locations in the piled rafts. The load settlement, load sharing, and bending moment of the raft were evaluated. An understanding of the pile behavior at different locations within the group will be helpful in selecting the suitable pile geometry during actual construction in the field. A foundation designed by considering the optimized pile length will be helpful in developing a more economical and resilient foundation system.
Numerical simulation of the uplift bearing behavior of pile foundations for transmission towers in expansive soil area
Authors: Zhong Yishun , Lü Xilin 
Published: May 2024

Abstract
Piles are commonly used as foundations for power transmission towers located in expansive soil areas. The strength of expansive soil is highly sensitive to the changing water content, which complicates the pile–soil interaction. In this study, a 3D elastoplastic finite element analysis of a typical pile foundation for a transmission tower in an expansive soil area was conducted to understand the effect of water content in expansive soil on the uplift bearing capacity of the pile foundation. The results that the failure mode of the pile foundation is almost unaffected by the water content. Shear failure was observed at the pile–soil interface, and, when the pile was pulled out, it lost its uplift bearing capacity. With the increasing water content of the soil, the ultimate uplift bearing capacity of the pile foundation exhibited a significant decreasing trend, whereas the displacement of soil around the pile became remarkable. The distribution of pile axial force and lateral frictional resistance during the uplift process was also evaluated. The pile axial force decreased gradually and at a higher rate with increasing depth. Once the pile reached the ultimate uplift bearing state, the pile lateral friction increased almost linearly with depth.
Bearing characteristics of a model piled raft foundation in unsaturated soil subjected to variations in the groundwater level
Authors: Xiong X. , Matsumoto T. 
Published: May 2024

Abstract
The bearing characteristics of a piled raft foundation (PRF) in saturated or dry soil ground have been investigated in previous studies. However, soils near the ground surface are generally in an unsaturated state. Matric suction occurs in unsaturated soils and influences the mechanical properties of soil. For more reasonable designs of PRFs, it is undoubtedly necessary to study the bearing characteristics of PRFs in unsaturated soil. In this study, model tests were conducted to investigate the bearing characteristics of a PRF in unsaturated soil subjected to variations in the groundwater level. The experimental results showed that, when the groundwater level was increased and the suction decreased, the load carried by the raft increased under dead load, leading to a significant settlement of the model PRF.
CPTU-based permeability evaluation of clays
Authors: Feng Hualei , Cai Guojun , Ouyang Zhongkun , He Huan , Mayne Paul W. 
Published: May 2024

Abstract
The piezocone penetration test (CPTU) is an efficient in-situ testing method for delineating subsurface stratigraphy and interpreting geoparameters continuously with depth. However, owing to the regional sensitivity and geological diversity, the applicability of CPTU-based geotechnical parameter evaluation methods is limited when applied to specific sites. This requires further scrutiny considering the different geological histories and local soil conditions. In this study, a database that included a collection of CPTU test sites in Jiangsu Province, China, was compiled containing high-quality sampling and laboratory testing performed to characterize the permeability of clay soils. Several published CPTU correlations for determining soil permeability were summarized and compared with laboratory-measured soil permeability as a benchmark reference. The evaluation results indicated that the I
c-based correlations can provide a reasonably good determination of the permeability for the investigated soils with root mean squared error of 0.89 and mean absolute error of 0.77. Finally, a modified approach was presented to evaluate the permeability coefficient of Jiangsu clay soils, which was calibrated using two additional case studies.
Field testing performance of prebored precast piles with enlarged base in soft ground
Authors: Wang WeiDong , Yang Yu , Wu Jiangbin , Qian Jiangu 
Published: May 2024

Abstract
Prebored precast piles with an enlarged base (PPEB piles) are constructed using an innovative and environmentally sustainable method, which notably reduces noise, soil squeezing, and mud discharge. Although PPEB piles have been widely applied in many cities in China, their bearing performance, including side friction and end resistances, on soft ground remains relatively unelucidated. This paper focuses on case studies of vertical-bearing PPEB piles based on a group of vertical static load field tests in Shanghai. The following conclusions are drawn: (1) Compared with traditional hammered-driven piles, PPEB piles exhibit better construction quality and load-bearing performance, as well as a relatively slow increment of settlement even under ultimate loading. (2) The resistance of the enlarged base section of the PPEB pile was approximately 16.3% of the total resistance under ultimate loading. (3) Compared with the values proposed in the Shanghai Foundation Design Code, the side friction resistance of the PPEB pile in deep silty sand (34.5–39 m) exhibited a considerable increase of approximately 156%. Additionally, the side friction in the soft ground was close to the values proposed in code. The case studies provide practical guidelines for the application of PPEB piles in soft ground.
A Comprehensive Review of the Evaluation and Application of Engineering Properties of Expansive Soil Based on Piezocone Penetration Test (CPTU)
Authors: Cai G J , Song D H , Liu L L , Liu X Y , Tian H L 
Published: May 2024

Abstract
Expansive soil presents several challenges in civil and geotechnical engineering because of its distinctive physical and mechanical properties, including considerable volumetric fluctuations, non-linear stress–strain behaviour, and high permeability. Owing to soil disturbances and sample size limitations during sampling, important parameters such as the expansive soil expansion force, compressive strength, and shear strength obtained through indoor experiments often cannot accurately reflect the values in situ. In this regard, in situ piezocone penetration testing has the advantages of small disturbances and high efficiency and has been widely used in subways, bridges, highways, and other engineering projects. This paper comprehensively summarizes the research progress of in situ testing technology in the evaluation and application of engineering properties of expansive soils in China and internationally. First, a detailed analysis of the basic theories and physical mechanisms of various in situ testing methods is provided, focusing on their applicability and accuracy in expansive soils. Second, examples of the application of in situ testing technology in expansive soil engineering are summarized. Finally, predictive models and methods based on in situ testing data, especially those that introduce cutting-edge models such as machine learning and advanced data analysis techniques, are discussed.