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Recent Progress on Advanced Foundation Engineering
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Recent Progress on Advanced Foundation Engineering

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Civil Engineering".

Deadline for manuscript submissions: closed (25 September 2022) | Viewed by 79673

Special Issue Editors

Prof. Dr. Guoliang Dai

E-Mail Website
Guest Editor
School of Civil Engineering, Southeast University, Nanjing 211189, China
Interests: foundation engineering; bridge foundation; geotechnical engineering
Prof. Dr. Fayun Liang

E-Mail Website
Guest Editor
Department of Geotechnical Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
Interests: offshore pile foundation; geotechnical earthquake engineering; soft soil engineering; deep-water foundation; scour and erosion
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Xinjun Zou

E-Mail Website
Guest Editor
School of Civil Engineering, Hunan University, Changsha 410082, China
Interests: foundation engineering; bridge foundation; geotechnical engineering

Special Issue Information

Dear Colleagues,

The stability of the foundation directly determines the safety of the superstructure. Thus, the foundation is very important to the superstructure. The type of foundations may include the pile, suction caisson foundation, diaphragm walling, composite foundation, deep water foundation, anchor foundation, and so on. With the development of modern technologies, innovative design concepts, intelligent test technologies, and advanced construction methods, we can modernize and upgrade our existing design concept and construction method. This Special Issue aims to collect the newest technology related to foundation engineering and the design for the future.

This Special Issue of Applied Sciences seeks to incorporate the latest developments in Recent Progress on Advanced Foundation Engineering, including the bearing characteristics of foundation, latest theoretical research, new type of foundation, innovative design concepts, intelligent test technologies, and advanced construction methods, so that readers and practitioners can make use of them in their own work.

Prof. Dr. Guoliang Dai
Prof. Dr. Fayun Liang
Prof. Dr. Xinjun Zou
Guest Editors

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Published Papers (31 papers)

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Research

26 pages, 6512 KiB  
Article
Modelling the Structure and Anisotropy of London Clay Using the SA_BRICK Model
by Vojkan Jovičić, Nina Jurečič and Gregor Vilhar
Appl. Sci. 2023, 13(2), 880; https://doi.org/10.3390/app13020880 - 9 Jan 2023
Cited by 1 | Viewed by 2344
Abstract
Several constitutive models had been developed by other researchers to cover the main features of mechanical behaviour of natural overconsolidated clays, such as the nonlinear stress–strain response at small and large strains, and the recent stress history effect. Kinematic hardening models include these [...] Read more.
Several constitutive models had been developed by other researchers to cover the main features of mechanical behaviour of natural overconsolidated clays, such as the nonlinear stress–strain response at small and large strains, and the recent stress history effect. Kinematic hardening models include these features to facilitate realistic predictions of soil–structure interaction. This paper presents the further development of a kinematic hardening model BRICK that includes anisotropy and the influence of soil structure on the mechanical behaviour of a natural clay. High quality laboratory tests were used to calibrate the input parameters of the model in a single element configuration, and a documented boundary value problem of tunnel excavation was used to validate the model in finite element calculations. A comprehensive comparative study between the predictions of different kinematic hardening models, using two different software packages, was carried out. It was observed that the SA_BRICK model is in fair agreement with the observed data and gives improved predictions in comparison to other kinematic hardening models, particularly in terms of narrowness of the settlement trough above the tunnel. Advanced predictions of ground deformations caused by tunnel excavations can be effectively used to mitigate possible damage of existing structures affected by tunnelling in an urban environment. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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17 pages, 6451 KiB  
Article
Experimental Study on Shear Behavior of Interface between Different Soil Materials and Concrete under Variable Normal Stress
by Hongyuan Liu, Mingxing Zhu, Xiaojuan Li, Guoliang Dai, Qian Yin, Jing Liu and Chen Ling
Appl. Sci. 2022, 12(21), 11213; https://doi.org/10.3390/app122111213 - 5 Nov 2022
Cited by 3 | Viewed by 1729
Abstract
At present, the interface shear test is mainly used to evaluate the anti-sliding performance of the new foundation base. However, the traditional interface shear test has certain limitations in simulating the load change during the construction process and cannot accurately simulate the interface [...] Read more.
At present, the interface shear test is mainly used to evaluate the anti-sliding performance of the new foundation base. However, the traditional interface shear test has certain limitations in simulating the load change during the construction process and cannot accurately simulate the interface shear characteristics between the structure and the soil under the continuous change of the normal stress. Based on the self-developed large-scale interface shear equipment, this paper carried out the interface shear test and mechanism research of cement soil concrete, sand concrete, clay concrete and other materials in different curing cycles under the loading and unloading modes of variable normal stress repeated steps and continuous loading modes of variable normal stress steps. In addition, this paper deduced the formula of the minimum interface friction coefficient based on Mohr–Coulomb criterion. The experimental results show that the curing effect of cement soil can significantly improve the shear mechanical properties of the interface, and the friction coefficient of the cement soil concrete interface will also increase step by step with the increase of the curing time of the cement soil. The sliding shear surface can be remolded under the preloading of normal pressure, so that the interface shear characteristics of each shear material under repeated loading and unloading can be approximately equal to the interface shear characteristics of multiple equivalent materials under separate loading. In the case of a continuous change of normal stress, the rapid increase of normal stress will lead to accelerated entry into the limit shear state, resulting in plastic failure of the shear plane as a whole. In the engineering with a continuous change of stress, the interface shear friction coefficient of the material with high cohesion fluctuates greatly. The minimum interface friction coefficient formula and test proposed in this paper can be used to evaluate the interface friction coefficient range, and the sand concrete interface shear performance under the continuous normal stress loading mode showed good consistency. The self-developed large-scale interface shearing equipment and its test data provide theoretical basis and solutions for the improvement of traditional interface shearing equipment. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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18 pages, 10922 KiB  
Article
Model Test of Micro-Pile Group Reinforcing High Steep Landslide
by Jinkai Yan, Xueling Liu, Zhichao Zhang, Kemo Jin and Xianzhui Lu
Appl. Sci. 2022, 12(19), 10017; https://doi.org/10.3390/app121910017 - 6 Oct 2022
Cited by 2 | Viewed by 1786
Abstract
High steep landslides are a major concern for infrastructure construction in the mountainous areas of Western China. The micro-pile technique has been gradually used to prevent landslides, due to convenient construction and good performance. However, the application of the micro-pile technique on landslide [...] Read more.
High steep landslides are a major concern for infrastructure construction in the mountainous areas of Western China. The micro-pile technique has been gradually used to prevent landslides, due to convenient construction and good performance. However, the application of the micro-pile technique on landslide prevention was generally implemented on the front edge of landslides, which is not applicable for the high steep landslides due to the limited operation space. In this study, a large-scale model test on the performance of a micro steep pile group on the prevention of high steep landsides was conducted in order to implement the micro-pile on the top of landslides. The force-deformation characteristics and failure modes of the steel pipe micro-pile group reinforcing high steep landslides were investigated. The test results showed that the landslide thrusts acting on the micro-pile group showed a triangle distribution. The maximum soil earth pressure was observed near the slip surface during landsides. The resistance of the micro pole group was distributed in an inverted triangle, mainly in the upper half of the loaded section. The sliding bed resistance is unevenly distributed along the height direction, and is larger near the slip surface. Once the landslide occurred, the force distribution of each row of steel pipe micro-piles was basically the same. The bending moment of the loaded section of the steel pipe micro-pile was mostly negative, with a larger bending moment in the range of eight times the pile diameter above the slip surface. The largest bending moment value is located at two times the pile diameter on the slip surface. On the other hand, the bending moment of the embedded section of the steel pipe micro-pile is mostly positive, showing a tension state with a maximum value at four times the pile diameter under the slip surface. This implies that the role of loaded and embedded sections of the micro-pile group on the landsides is different. The failure mode of the micro-pile group was mainly attributable to the bending failure within eight times the pile diameter above and below the slip surface. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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17 pages, 4269 KiB  
Article
Field Test Study on Vertical Bearing Characteristics of Coal Rock
by Yun Miao and Xudong Wang
Appl. Sci. 2022, 12(18), 9301; https://doi.org/10.3390/app12189301 - 16 Sep 2022
Viewed by 1561
Abstract
Coal rock is rarely used as the foundation bearing strata. For buildings located on coal rock, it is a reasonable and feasible way to obtain the vertical bearing characteristics of coal rock through field tests. Three plate load tests and two bi-directional load [...] Read more.
Coal rock is rarely used as the foundation bearing strata. For buildings located on coal rock, it is a reasonable and feasible way to obtain the vertical bearing characteristics of coal rock through field tests. Three plate load tests and two bi-directional load tests were carried out, and the design parameters of the vertical bearing capacity of the shallow foundation and the deep foundation were obtained, respectively. The plate load test results show that the pressure–settlement curve of coal rock is a steep-drop-type, and the deformation modulus decreases with the increase of the pressure. The bi-directional load test results show that the unit tip resistance-displacement curve of coal rock is a steep-drop-type, and the load transfer function of the unit tip resistance is an ideal elastic–plastic curve, and the displacement value corresponding to the ultimate bearing capacity is about 1% of the pile diameter. The load transfer function of the unit side resistance of coal rock is a hyperbolic curve. The equivalent pile top load–settlement curve obtained according to the load transfer functions of the unit tip resistance and the unit side resistance is consistent with the equivalent conversion results of the bi-directional load test method. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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18 pages, 6563 KiB  
Article
Experimental Study on Lateral and Vertical Capacity of Piled Raft and Pile Group System in Sandy Soil
by Irfan Jamil, Irshad Ahmad, Wali Ullah, Mahmood Ahmad, Mohanad Muayad Sabri Sabri and Ali Majdi
Appl. Sci. 2022, 12(17), 8853; https://doi.org/10.3390/app12178853 - 2 Sep 2022
Cited by 3 | Viewed by 2466
Abstract
In deep foundations, the pile group and the pile raft are generally used. To date, the contribution of the raft is not taken into account in the design, even when the raft is in contact with the soil and the whole system is [...] Read more.
In deep foundations, the pile group and the pile raft are generally used. To date, the contribution of the raft is not taken into account in the design, even when the raft is in contact with the soil and the whole system is therefore considered to work as a pile group foundation. In a combined pile raft system, the raft takes a considerable portion of the applied load, depending upon the number of piles, the spacing to diameter ratio of the piles, and the length to diameter ratio. In this paper, an experimental investigation is carried out to study the response of small-scale pile group and piled raft models with a varying number of piles subjected to both vertical and lateral loads. Additionally, the response mechanism of these models to both types of loads is also studied. A comparison was made between these models. It was found that, unlike the pile group, the piled raft provides considerably high stiffness to both types of loads, and the difference between the stiffness of both systems decreases as the number of piles increases. By comparing the response of the piled raft and the pile group with the same number of piles under the same vertical and lateral load, it was concluded that the piled raft response to the lateral and vertical loads was much stiffer than the pile group response. The lateral deflection and the vertical settlement of the piled raft were less than those of the pile group with the same pile configuration. This effective response of the piled raft to the vertical and lateral loads was due to the raft contribution in resisting the vertical and lateral loads. Moreover, with the increase in the number of piles, the vertical and lateral contribution of the raft decreases. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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20 pages, 7380 KiB  
Article
Study on Creep Behavior of Silty Clay Based on Fractal Derivative
by Qian Yin, Junping Dai, Guoliang Dai, Weiming Gong, Fan Zhang and Mingxing Zhu
Appl. Sci. 2022, 12(16), 8327; https://doi.org/10.3390/app12168327 - 20 Aug 2022
Cited by 5 | Viewed by 1520
Abstract
Soft soil is widely distributed in the riverside area of southern China. The creep deformation characteristics of the soft soil affect the long-term stability of the structure foundation, which cannot be ignored. Through the triaxial drainage creep test, the creep characteristics of riverside [...] Read more.
Soft soil is widely distributed in the riverside area of southern China. The creep deformation characteristics of the soft soil affect the long-term stability of the structure foundation, which cannot be ignored. Through the triaxial drainage creep test, the creep characteristics of riverside soil with a soft interlayer from Jiangsu Province were studied. The test results show that the creep procedure of the soft soil is divided into two stages, exhibiting steady-state creep and shear shrinkage characteristics with time and stress growth, which presents typical nonlinear behavior. Additionally, the confining pressure and stress are critical factors affecting creep characteristics. The fractal dashpot based on fractal derivative theory is introduced in place of the Abel dashpot in the classical fractional Burgers model; a fractal Burgers creep model with few parameters, high precision, and clear physical significance is established. Additionally, an analytical solution to the creep model is given. The model parameters are determined by fitting the test results, and the comparison shows that the results estimated with the model are more accurate than those estimated with the traditional model. The sensitivity analyses of the model parameters reveal the influence of key parameters on the creep characteristics of the soil. The results further confirm that the proposed fractal Burgers model can characterize the creep behavior of viscoelastic soil. These observations are extremely important for predicting the foundation displacement and formulating measures to prevent the deformation, which can provide a reference for engineering applications in the riverside area of southern China. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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14 pages, 4304 KiB  
Article
Centrifuge Model Investigation of Interaction between Successively Constructed Foundation Pits
by Shangrong Chen, Jifei Cui and Fayun Liang
Appl. Sci. 2022, 12(16), 7975; https://doi.org/10.3390/app12167975 - 9 Aug 2022
Cited by 7 | Viewed by 1780
Abstract
A series of centrifuge model tests were conducted to study the interaction between successively constructed adjacent foundation pits. The stress, deformation, and earth pressure on retaining structures and the settlement of the soil between the two adjacent foundation pits during successive construction were [...] Read more.
A series of centrifuge model tests were conducted to study the interaction between successively constructed adjacent foundation pits. The stress, deformation, and earth pressure on retaining structures and the settlement of the soil between the two adjacent foundation pits during successive construction were investigated by a comprehensive instrumentation program. To reveal the effect of the construction sequence, both the stress and deformation of successively constructed foundation pits were compared. The results showed that the stress and deformation of the retaining structure in the foundation pit constructed first were larger than those in the foundation pit constructed later. Due to the inward displacement of the soil around the foundation pits excavated first, the first strut of the foundation pit constructed later underwent high tension during the construction of the first foundation pit. The lateral deformation of the retaining structure of the foundation pit excavated first increased with the increase of the excavation depth. However, the excavation of the second foundation pit reduced the earth pressure on the retaining wall between the two excavations, thus leading to the recovery of the inward deformation in the first excavation. However, the top of the retaining wall deformed into the first foundation pit during the whole construction. The settlement of the soil between the two foundation pits showed a superposition effect. During the construction of the two foundation pits, the settlement of the soil between them kept increasing. The active earth pressure on the middle wall of the foundation pit constructed later was lower than that on the middle wall of the first foundation pit. The excavation of the foundation pit constructed later had no significant effect on the passive earth pressure of the first foundation pit. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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16 pages, 10433 KiB  
Article
Bulk and Rayleigh Waves Propagation in Three-Phase Soil with Flow-Independent Viscosity
by Qing Guo, Hongbo Liu, Guoliang Dai and Zhongwei Li
Appl. Sci. 2022, 12(14), 7166; https://doi.org/10.3390/app12147166 - 16 Jul 2022
Cited by 1 | Viewed by 1500
Abstract
The flow-independent viscosity of the soil skeleton has significant influence on the elastic wave propagation in soils. This work studied the bulk and Rayleigh waves propagation in three-phase viscoelastic soil by considering the contribution of the flow-independent viscosity from the soil skeleton. Firstly, [...] Read more.
The flow-independent viscosity of the soil skeleton has significant influence on the elastic wave propagation in soils. This work studied the bulk and Rayleigh waves propagation in three-phase viscoelastic soil by considering the contribution of the flow-independent viscosity from the soil skeleton. Firstly, the viscoelastic dynamic equations of three-phase unsaturated soil are developed with theoretical derivation. Secondly, the explicit characteristic equations of bulk and Rayleigh waves in three-phase viscoelastic soil are yielded theoretically by implementing Helmholtz resolution for the displacement vectors. Finally, the variations of the motion behavior for bulk and Rayleigh waves with physical parameters such as relaxation time, saturation, frequency, and intrinsic permeability are discussed by utilizing calculation examples and parametric analysis. The results reveal that the influence of soil flow-independent viscosity on the wave speed and attenuation coefficient of bulk and Rayleigh waves is significantly related to physical parameters such as saturation, intrinsic permeability, and frequency. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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15 pages, 3699 KiB  
Article
Low-Cycle Reverse Loading Tests of the Continuous Basalt Fiber-Reinforced Polymer Column Filled with Concrete
by Jianhang Li, Hongbo Liu, Qing Guo, Guoliang Dai, Junlong Zhou and Penglin Xie
Appl. Sci. 2022, 12(13), 6359; https://doi.org/10.3390/app12136359 - 22 Jun 2022
Cited by 2 | Viewed by 1738
Abstract
The continuous basalt fiber-reinforced polymer column filled with concrete (BFRPC composite column) can well resist the erosion of the external environment, improve the durability of the structure, and reduce the life-cycle cost of the project. To evaluate the mechanical behaviors of the BFRPC [...] Read more.
The continuous basalt fiber-reinforced polymer column filled with concrete (BFRPC composite column) can well resist the erosion of the external environment, improve the durability of the structure, and reduce the life-cycle cost of the project. To evaluate the mechanical behaviors of the BFRPC composite column under cyclic lateral loading, laboratory low-cycle reverse loading tests were implemented on a BFRPC composite column specimen, a prestressed reinforced concrete (PRC) tube column specimen, and a prestressed high-strength concrete (PHC) tube column specimen. The failure features, hysteretic curve, and skeleton curve for these three types of column specimens were compared and analyzed through the load–displacement hysteretic curve. The results indicated that the BFRPC composite column possesses the better bearing capacity and deformation performance. The horizontal bearing capacity of the BFRPC composite column is at least three times better than that of PHC and PRC tube columns. Finally, the functional expression of the skeleton curves for the BFRPC composite column is fitted by the rational function fitting method. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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15 pages, 8174 KiB  
Article
Case Study on the Deformation Coupling Effect of a Deep Foundation Pit Group in a Coastal Soft Soil Area
by Shangrong Chen, Jifei Cui and Fayun Liang
Appl. Sci. 2022, 12(12), 6205; https://doi.org/10.3390/app12126205 - 18 Jun 2022
Cited by 20 | Viewed by 2342
Abstract
Simultaneous construction of adjacent projects may lead to emergencies in a foundation pit group, which significantly affects the deformation and safety of foundation pits. In this study, the deformation characteristics of a deep foundation pit group and the mutual interactions among the adjacent [...] Read more.
Simultaneous construction of adjacent projects may lead to emergencies in a foundation pit group, which significantly affects the deformation and safety of foundation pits. In this study, the deformation characteristics of a deep foundation pit group and the mutual interactions among the adjacent foundation pits were observed by a monitoring system during excavation. Field data of the foundation pit group, including the lateral deflections of the enclosure pile, the ground subsidence, as well as the vertical column movements, were analyzed and compared with individual excavations in Shanghai. The field data showed that the excavation of the adjacent foundation pit reduced the lateral deformation of the enclosure structure, caused by the reduction of active earth pressure acting on the retaining pile. Furthermore, the foundation pit excavated later caused upward movements of the soil between them. However, the foundation pit excavated earlier had a negligible influence on the vertical column movements of the foundation pit excavated later. Due to the optimized excavation sequence of the deep foundation pit group, the deformation of this special excavation was well controlled. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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14 pages, 2054 KiB  
Article
Method for Calculating Vertical Compression Bearing Capacity of the Static Drill Rooted Nodular Pile
by Jing Guo, Guoliang Dai and Yue Wang
Appl. Sci. 2022, 12(10), 5101; https://doi.org/10.3390/app12105101 - 18 May 2022
Cited by 2 | Viewed by 2275
Abstract
The static drill rooted nodular (SDRN) pile is a new kind of composite pile foundation made by inserting a precast nodular pile into the cemented soil. Based on the tests and analysis on the mechanism characteristics of these two kinds of interfaces, which [...] Read more.
The static drill rooted nodular (SDRN) pile is a new kind of composite pile foundation made by inserting a precast nodular pile into the cemented soil. Based on the tests and analysis on the mechanism characteristics of these two kinds of interfaces, which are between the pile and cemented soil, and between the cemented soil and soil, this paper proposes a calculation method for the ultimate vertical bearing capability of the SDRN pile considering two failure modes. When the precast pile and surrounding cemented soil fails as a whole, the diameter of the cemented soil pile is taken to calculate the ultimate shaft resistance, and the shaft resistance of the SDRN pile is about 1.05∼1.10 times that of the bored pile in the same soil layer. When the core precast pile fails in penetration mode, the diameter of the core pile is taken. The pile shaft resistance takes that of displacement piles in the same soil layer. The lower nodular pile shaft resistance should consider the squeezing effect of nodular joints. Besides, the improvement of pile tip resistance due to the expanded cemented soil should also be taken into consideration. The result is the smaller value calculated according to these two failure modes. The ultimate bearing capacity of a SDRN pile calculated by the theoretical method is not only compared with the field test result, but also the simulation result of a 2D model pile built by PLAXIS finite element software. In addition, the finite element simulation is also confirmed to be an effective way to investigate the mechanism characteristics of SDRN piles more thoroughly. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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18 pages, 3742 KiB  
Article
Numerical Study on the Deformation of Tunnels by Excavation of Foundation Pit Adjacent to the Subway
by Xiang Zhao, Hanxuan Wang, Zhongwei Li, Guoliang Dai, Ziwei Yin, Shuning Cao and Junlong Zhou
Appl. Sci. 2022, 12(9), 4752; https://doi.org/10.3390/app12094752 - 9 May 2022
Cited by 24 | Viewed by 2222
Abstract
The excavation of the foundation pit will cause changes in the soil stress field around the foundation pit, and that may have adverse effects on the adjacent subway tunnels. In this paper, a complex deep foundation pit excavated in different sections is taken [...] Read more.
The excavation of the foundation pit will cause changes in the soil stress field around the foundation pit, and that may have adverse effects on the adjacent subway tunnels. In this paper, a complex deep foundation pit excavated in different sections is taken as the research object, and the support structure of the complex foundation pit project is introduced, which accumulates experience in the selection of support structure for similar projects. The finite element models are established by MIDAS/GTS software to evaluate the influence of excavation in different sections of the foundation pit on the tunnel deformation, and the accuracy of the finite element calculation results is verified by comparing the monitoring data. The results show that: The horizontal deformation of the subway tunnel is generally smaller than the vertical deformation. Tunnel monitoring should focus more on the development of the vertical deformation of the tunnel. The maximum vertical deformation and horizontal deformation of the tunnel are both smaller than the local specification limits, and the excavation of the foundation pit in this project has little influence on the deformation of the subway tunnel. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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18 pages, 10059 KiB  
Article
Numerical Study on the Effect of Large Deep Foundation Excavation on Underlying Complex Intersecting Tunnels
by Xiang Zhao, Zhongwei Li, Guoliang Dai, Hanxuan Wang, Ziwei Yin and Shuning Cao
Appl. Sci. 2022, 12(9), 4530; https://doi.org/10.3390/app12094530 - 29 Apr 2022
Cited by 15 | Viewed by 1774
Abstract
The effect of large deep foundation excavations on the surrounding existing tunnels is a problem that cannot be avoided in the current construction background. This effect is difficult to assess precisely, especially when the geometry of the tunnels and pits is complex. In [...] Read more.
The effect of large deep foundation excavations on the surrounding existing tunnels is a problem that cannot be avoided in the current construction background. This effect is difficult to assess precisely, especially when the geometry of the tunnels and pits is complex. In this paper, a three-dimensional (3D) finite element model has been developed based on a case containing four complex intersecting tunnels and a large deep foundation pit. The model used the hardening soil model with small-strain stiffness (HSS) and the Hoek–Brown (HB) model to describe the mechanical properties of the soil and rock, and various methods including the standard penetration test (SPT) and heavy dynamic penetration test (HDPT) were used to determine the model parameters. The results of the analysis are as follows: the excavation of the foundation pit caused the tunnels to heave and the heave deformation conforms to the normal distribution; the maximum heave of numerical simulation is 3.1 mm which is consistent with the field data; the horizontal displacement, horizontal convergence, and vertical convergence of the tunnels caused by the excavation of the pits are small, and all kinds of deformations meet the control requirements; the intersection of multiple tunnels shows obvious stress concentration when the tunnels were constructed, and the lining stress slightly decreases as excavation progresses. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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19 pages, 6201 KiB  
Article
Lateral Loading of a Rock–Socketed Pile Using the Strain Wedge Model Based on Hoek–Brown Criterion
by Feng Xu, Guoliang Dai, Weiming Gong, Xueliang Zhao and Fan Zhang
Appl. Sci. 2022, 12(7), 3495; https://doi.org/10.3390/app12073495 - 30 Mar 2022
Cited by 4 | Viewed by 3589
Abstract
Rock–socketed pile under lateral loading is important in engineering practice. It is very significant to calculate the lateral bearing capacity of rock–socketed piles since few studies focus on this problem. The rock cohesion and instantaneous angle of friction, which have a high correlation [...] Read more.
Rock–socketed pile under lateral loading is important in engineering practice. It is very significant to calculate the lateral bearing capacity of rock–socketed piles since few studies focus on this problem. The rock cohesion and instantaneous angle of friction, which have a high correlation with confining pressure, are obtained. Moreover, the strain wedge model is modified from three aspects: the assumption of nonlinear displacement; the stress level related to cohesion and friction angle; and the pile side resistance. Then, the modified strain wedge model is employed to deduce p–y criterion for rock–socketed pile considering Hoek–Brown failure criterion. The fourth-order partial differential equation constructed according to the p–y curve is solved by using the finite difference method. A numerical method with 2 m diameter rock-socketed pile is given to validate the rationality of the proposed method. It is shown that the proposed could predict the pile deformation well, and the responses are considered acceptable. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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17 pages, 4277 KiB  
Article
Shear Behaviour of Aeolian Sand with Different Density and Confining Pressure
by Xuefeng Li, Wendong Xu, Lei Chang and Wenwei Yang
Appl. Sci. 2022, 12(6), 3020; https://doi.org/10.3390/app12063020 - 16 Mar 2022
Cited by 7 | Viewed by 2432
Abstract
Different from the other roadbed material, the unique mechanical properties of aeolian sand bring great difficulties to the construction and maintenance of desert highways. However, the main attention was usually paid to the engineering properties of aeolian sand, such as collapsibility, strong permeability, [...] Read more.
Different from the other roadbed material, the unique mechanical properties of aeolian sand bring great difficulties to the construction and maintenance of desert highways. However, the main attention was usually paid to the engineering properties of aeolian sand, such as collapsibility, strong permeability, and poor gradation. To investigate the shear behaviour of aeolian sand under different engineering conditions, the drained and undrained tests were performed on aeolian sand with relatively large range of density and confining pressure. Under this condition, both the drained and undrained tests tend to the same critical state line, and the shear behaviour of aeolian sand is directly dependent on its density. Under the undrained condition, the q-ε1 curves and the effective stress paths in triaxial stress space exhibit four types of undrained shear behaviour, such as flow, limited flow, strain hardening, and strain softening. Meanwhile all the specimens exhibit three types of failure, such as flow slip, bulging failure, and shear bands. In the q-p’ plane, the analogous drained and undrained stress paths can be followed by aeolian sand with same initial relative density but different confining pressures, and there are two critical state lines due to the generation of shear bands for dense sand. In addition, the critical state lines in e-lnp’ plane decrease with increasing initial relative density Dr, that is, the material constant eᴦ decreases with increasing Dr, and the λ is also not constant but decreases with the increase in Dr. The results suggest that the strength behaviours of aeolian sand can be fitted by a straight line considering relative density and confining pressure and that two empirical formulas are established to describe this feature. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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17 pages, 7735 KiB  
Article
Investigation on the Influencing Factors of K0 of Granular Materials Using Discrete Element Modelling
by Jiangu Qian, Chuang Zhou, Weiyi Li, Xiaoqiang Gu, Yongjun Qin and Liangfu Xie
Appl. Sci. 2022, 12(6), 2899; https://doi.org/10.3390/app12062899 - 11 Mar 2022
Cited by 4 | Viewed by 2569
Abstract
Earth pressure coefficient at rest K0 is commonly estimated by empirical equations, which to date has had insufficient accuracy and universality. For better prediction, the investigation on the factors influencing K0 is required. A series of discrete element method (DEM) simulations [...] Read more.
Earth pressure coefficient at rest K0 is commonly estimated by empirical equations, which to date has had insufficient accuracy and universality. For better prediction, the investigation on the factors influencing K0 is required. A series of discrete element method (DEM) simulations of oedometer tests are conducted to verify the key factors influencing K0 of granular materials. The influences of initial fabric anisotropy, particle shape, initial void ratio, inter-particle friction angle is investigated. The evolution of microstructure is monitored during the tests to reveal the relationship between the microstructure evolution and K0 values. The results show that the effect of fabric anisotropy exists but is limited. Particle shape, initial void ratio, and inter-particle friction angle all significantly affect the K0 values alone. According to the DEM results, an attempt is made to propose a more reasonable empirical equation in which K0 is a function of relative density, critical state friction angle, and “shape factor”. This new empirical equation has higher accuracy and can consider the effect of particle shape, inspiring the determination of K0 values in practical engineering. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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19 pages, 3450 KiB  
Article
Axial Bearing Mechanism of Post-Grouted Piles in Calcareous Sand
by Zhihui Wan, Heng Liu, Feng Zhou and Guoliang Dai
Appl. Sci. 2022, 12(5), 2731; https://doi.org/10.3390/app12052731 - 7 Mar 2022
Cited by 11 | Viewed by 2799
Abstract
Post-grouted piles, as a foundation form for large-span and large-scale structures on calcareous sand, are expected to provide a high bearing capacity, but research on the response of post-grouted piles subjected to axial load in calcareous sand is still in the exploratory stage. [...] Read more.
Post-grouted piles, as a foundation form for large-span and large-scale structures on calcareous sand, are expected to provide a high bearing capacity, but research on the response of post-grouted piles subjected to axial load in calcareous sand is still in the exploratory stage. In this paper, a model test is constructed for static pressure piles in calcareous sand under axial loading. The response of axial compressive piles, with and without post-grouting, in calcareous sand were investigated, and the test results were compared with those of axial compressive piles, with and without post-grouting, in siliceous sand. The influence of post-side-grouting on the response of a single pile subjected to axial compressive load in calcareous sand and its bearing mechanism were further analyzed. The results show that the change in shaft resistance, caused by the lateral extrusion of calcareous sand, is less than the negative effect caused by particle breakage during pile driving, so single piles without post-grouting in calcareous sand exhibit weaker axial bearing behavior than that in siliceous sand. A single pile with post-side-grouting in calcareous sand can provide a higher bearing capacity by increasing the shaft resistance and tip resistance compared with a single pile without post-side-grouting, and the increased ratio of the bearing capacity of piles, after grouting in calcareous sand, is better than that of piles in siliceous sand. Post-side-grouting can not only strengthen the surrounding soil by the solidification effect of injected cement grout, but it can also have a strengthening effect on the tip resistance. In addition, ideal-geometry grouting has more obvious advantages in improving the bearing behavior of pile foundations than annular point grouting, and higher stability in improving the bearing properties of pile foundations is evident for ideal-geometry grouting. Therefore, it is suggested that a directional grouting device should be adopted in actual projects in the future to form a more stable pile-soil interaction system and to expand the application prospect of pile foundations in calcareous sand. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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14 pages, 11997 KiB  
Article
Experimental Study of Wave-Induced Response of Piles in Seabed with Various Permeability
by Ting Huang, Yinghui Tian, Guoliang Dai and Ao Jiao
Appl. Sci. 2022, 12(5), 2698; https://doi.org/10.3390/app12052698 - 4 Mar 2022
Cited by 1 | Viewed by 1801
Abstract
Subjected to continuous wave loading, the responses of pile foundations and seabed develop gradually, severely affecting the serviceability of piled structures. This paper presents the results of a series of flume experiments on pile foundations in fine sandy and silty seabed under regular [...] Read more.
Subjected to continuous wave loading, the responses of pile foundations and seabed develop gradually, severely affecting the serviceability of piled structures. This paper presents the results of a series of flume experiments on pile foundations in fine sandy and silty seabed under regular wave loading. Pile-head displacement and pore water pressure were measured and the effects of pile diameter, cross-section, pile stiffness and wave height were investigated. The experimental results indicate that the pore pressure in fine sandy seabed varied only slightly even under 640 s of wave loading but showed an increase of 15.7–25.9% around a pile. In silty seabed with much lower permeability, pore pressure accumulated quickly due to piles and oscillated impressively at the depth of soil liquefaction. Based on the comparison between the calculated and measured pile-head displacement, we found that the response of smaller-diameter piles in lower-permeability seabed was much more easily magnified by the induced pore pressure. Increasing the pile diameter and attaching fins could lead to a smaller response of piles. Wave height was a major factor in the experiments that affected the development of response. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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16 pages, 5132 KiB  
Article
Study on the Dynamic Response Characteristics and p–y Curve of Straight and Inclined Pile Groups in Saturated Sands
by Yurun Li, Jian Zhang, Huabin Chen, Dongfeng Qiang and Yongzhi Wang
Appl. Sci. 2022, 12(5), 2363; https://doi.org/10.3390/app12052363 - 24 Feb 2022
Cited by 6 | Viewed by 1706
Abstract
This paper is based on a shaking table test of 2 × 2 straight pile groups and 2 × 2 inclined pile groups in non-liquefied sand and saturated sand with different thicknesses. Under the sine wave with a certain peak acceleration and frequency, [...] Read more.
This paper is based on a shaking table test of 2 × 2 straight pile groups and 2 × 2 inclined pile groups in non-liquefied sand and saturated sand with different thicknesses. Under the sine wave with a certain peak acceleration and frequency, the lateral dynamic response characteristics, the distribution law of the maximum bending moment envelope diagram, and the p–y curve of the straight and inclined pile groups are studied. The results show that the bending moment of the straight pile group is 3~4 times that of the inclined pile group at the bottom section of the pile in the 300 mm saturated sand. When the thickness of the saturated sand increases to 380 mm, the maximum bending moment of the straight pile group is 6~7 times that of the inclined pile group at the bottom section of the pile. Through the comparison of indicators, it shows that the inclined pile group can have better bending resistance when subjected to the same lateral dynamic load. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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24 pages, 3244 KiB  
Article
Prediction of Pile Bearing Capacity Using XGBoost Algorithm: Modeling and Performance Evaluation
by Maaz Amjad, Irshad Ahmad, Mahmood Ahmad, Piotr Wróblewski, Paweł Kamiński and Uzair Amjad
Appl. Sci. 2022, 12(4), 2126; https://doi.org/10.3390/app12042126 - 18 Feb 2022
Cited by 99 | Viewed by 7865
Abstract
The major criteria that control pile foundation design is pile bearing capacity (Pu). The load bearing capacity of piles is affected by the various characteristics of soils and the involvement of multiple parameters related to both soil and foundation. In this [...] Read more.
The major criteria that control pile foundation design is pile bearing capacity (Pu). The load bearing capacity of piles is affected by the various characteristics of soils and the involvement of multiple parameters related to both soil and foundation. In this study, a new model for predicting bearing capacity is developed using an extreme gradient boosting (XGBoost) algorithm. A total of 200 driven piles static load test-based case histories were used to construct and verify the model. The developed XGBoost model results were compared to a number of commonly used algorithms—Adaptive Boosting (AdaBoost), Random Forest (RF), Decision Tree (DT) and Support Vector Machine (SVM) using various performance measure metrics such as coefficient of determination, mean absolute error, root mean square error, mean absolute relative error, Nash–Sutcliffe model efficiency coefficient and relative strength ratio. Furthermore, sensitivity analysis was performed to determine the effect of input parameters on Pu. The results show that all of the developed models were capable of making accurate predictions however the XGBoost algorithm surpasses others, followed by AdaBoost, RF, DT, and SVM. The sensitivity analysis result shows that the SPT blow count along the pile shaft has the greatest effect on the Pu. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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21 pages, 2426 KiB  
Article
Dynamic Lateral Response of the Partially-Embedded Single Piles in Layered Soil
by Jianjun Ma, Shujuan Han, Xiaojuan Gao, Da Li, Ying Guo and Qijian Liu
Appl. Sci. 2022, 12(3), 1504; https://doi.org/10.3390/app12031504 - 30 Jan 2022
Cited by 5 | Viewed by 2479
Abstract
Scouring can reduce the strength and rigidity of the pile–soil system and become one of the major causes for the failure of the structure of the partially-embedded single pile. The stratification of the soil fields has a significant influence on the internal force [...] Read more.
Scouring can reduce the strength and rigidity of the pile–soil system and become one of the major causes for the failure of the structure of the partially-embedded single pile. The stratification of the soil fields has a significant influence on the internal force and deformation of laterally-loaded piles. A dynamic model of the laterally-loaded single pile in layered soil is established employing Hamilton’s principle based on the modified Vlasov foundation model. Then, the finite difference method is used to obtain the numerical matrix containing the control equations of the single pile to achieve accurate modeling of the soil–structure interaction (SSI) system affected by scouring, so as to solve the natural frequencies of the single pile. Green’s function method obtains the analytical solution of the forced vibration of the single pile. The effects of scouring and the layered soil on the dynamic response of the single pile are studied by numerical calculation and parameter analysis. It is shown that the dynamic model of the partially-embedded single pile in layered soil based on the modified Vlasov foundation model can accurately predict the dynamic characteristics of pile foundation affected by scouring. As the scouring degree intensifies, the first-order natural frequencies of the single pile in layered soil decrease significantly. The subgrade reaction coefficient of each layer of soil in the modified Vlasov foundation model decreases, and the shear coefficient increases. The first-order natural frequencies of the single pile at each scour level increase with the increase in the thickness of the underlying soil. When the elastic modulus of the first layer of soil is increased by one time, the first-order natural frequencies of the single pile are increased by about 20%. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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14 pages, 8810 KiB  
Article
Responses of Laterally Loaded Single Piles Subjected to Various Loading Rates in a Poroelastic Soil
by Meen-Wah Gui and Alex A. Alebachew
Appl. Sci. 2022, 12(2), 617; https://doi.org/10.3390/app12020617 - 10 Jan 2022
Cited by 5 | Viewed by 2206
Abstract
Groundwater table has an important role in soil–structure interaction problems. However, analysis of laterally loaded single piles has often been conducted by solely considering the mechanics of the soil skeleton or decoupling the interactive mechanics of the soil skeleton and the fluid flux; [...] Read more.
Groundwater table has an important role in soil–structure interaction problems. However, analysis of laterally loaded single piles has often been conducted by solely considering the mechanics of the soil skeleton or decoupling the interactive mechanics of the soil skeleton and the fluid flux; in other words, most analyses were performed without taking into consideration the coupling effect between the soil skeleton and the fluid flux. To improve our understanding of the hydromechanical coupling effect on laterally loaded single piles, a series of finite element study on laterally loaded single piles in saturated porous media was conducted. The effect of pile cap geometries, cap widths, cap embedment depths, and pile lengths, on the response of laterally loaded single piles was also studied. The loading condition of the pile was found to have a significant effect on the generation of excess pore-water pressure. The lateral displacement and bending moment computed at the maximum excess pore water pressure, which in turn, is equivalent to an undrained analysis, produced the minimum responses among all the other loading conditions. The effect of pile cap geometries was found to be much less significant than anticipated. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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24 pages, 3679 KiB  
Article
Undrained Elastoplastic Solution for Cylindrical Cavity Expansion in Structured Cam Clay Soil Considering the Destructuration Effects
by Zhanghui Zhai, Yaguo Zhang, Shuxiong Xiao and Tonglu Li
Appl. Sci. 2022, 12(1), 440; https://doi.org/10.3390/app12010440 - 3 Jan 2022
Cited by 4 | Viewed by 2185
Abstract
Soil structure has significant influences on the mechanical behaviors of natural soils, although it is rarely considered in previous cavity expansion analyses. This paper presents an undrained elastoplastic solution for cylindrical cavity expansion in structured soils, considering the destructuration effects. Firstly, a structural [...] Read more.
Soil structure has significant influences on the mechanical behaviors of natural soils, although it is rarely considered in previous cavity expansion analyses. This paper presents an undrained elastoplastic solution for cylindrical cavity expansion in structured soils, considering the destructuration effects. Firstly, a structural ratio was defined to denote the degree of the initial structure, and the Structured Cam Clay (SCC) model was employed to describe the subsequent stress-induced destructuration, including the structure degradation and crushing. Secondly, combined with the large strain theory, the considered problem was formulated as a system of first-order differential equations, which can be solved in a simplified procedure with the introduced auxiliary variable. Finally, the significance and efficiency of the present solution was demonstrated by comparing with the previous solutions, and parametric studies were also conducted to investigate the effects of soil structure and destructuration on the cavity expansion process. The results show that the soil structure has pronounced effects on the mechanical behavior of structured soils around the cavity. For structured soils, a cavity pressure that is larger than the corresponding reconstituted soils when the cavity expands to the same radius is required, and the effective stresses first increase to a peak value before decreasing rapidly with soil structure degradation and crushing. The same final critical state is reached for soils with different degrees of the initial structure, which indicates that the soil structure is completely destroyed during the cavity expansion. With the increase of the destructuring index, the soil structure was destroyed more rapidly, and the stress release during the plastic deformation became more significant. Moreover, the present solution was applied in the jacking of a casing during the sand compact pile installation and in situ self-boring pressuremeter (SBPM) tests, which indicates that the present solution provides an effective theoretical tool for predicting the behavior of natural structured soils around the cavity. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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21 pages, 10413 KiB  
Article
Deformation Characteristic of a Supported Deep Excavation System: A Case Study in Red Sandstone Stratum
by Weizheng Liu, Tianxiong Li and Jiale Wan
Appl. Sci. 2022, 12(1), 129; https://doi.org/10.3390/app12010129 - 23 Dec 2021
Cited by 11 | Viewed by 4415
Abstract
A complete case record of a deep foundation pit with pile-anchor retaining structure excavated in red sandstone stratum is presented in this study. The horizontal displacement of pile top, the horizontal displacement at various depths, the axial force of anchor cable, and ground [...] Read more.
A complete case record of a deep foundation pit with pile-anchor retaining structure excavated in red sandstone stratum is presented in this study. The horizontal displacement of pile top, the horizontal displacement at various depths, the axial force of anchor cable, and ground settlement during construction are measured. A three-dimensional numerical model is established to analyze the additional stress and deformation induced by the excavation and the accuracy of the FEM model is verified by comparing with field measured results. Both the measured and numerical simulation results show that the deformation of the pile-anchor supported deep excavation is significantly affected by the spatial effect. The results show that the deformation in the middle of the foundation pit is greater than the pit angle and that the deformation of the long side is greater than that of the short side and gradually decreases from the middle to the pit angle. The deformation and stress in the middle of the long side of the foundation pit are the largest, which is the most unfavorable part. With the increase of vertical excavation depth, the spatial effects tend to increase, and the influence scope of spatial effects is about five times the vertical excavation depth in the red sandstone stratum. The ground settlement outside the pit is mainly distributed in a groove shape, and the maximum settlement occurs about 8.5 m away from the pit edge. Finally, parametric studies of reinforcement parameters indicated that 1.5–2.0 times the initial elastic modulus and cohesive force of soil should be used for reinforcement. It is recommended that the ranges for pile diameter, pile spacing, anchor cable prestressing and inclination angle should be selected as 0.8–1.2 m, 1.4–2.0 m, 100–150 kN, and 10°–20°, respectively. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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11 pages, 6541 KiB  
Article
Incorporating Setup Effects into the Reliability Analysis of Driven Piles
by Xiaoya Bian, Jiawei Chen, Xixuan Bai and Kunpeng Zheng
Appl. Sci. 2022, 12(1), 2; https://doi.org/10.3390/app12010002 - 21 Dec 2021
Cited by 1 | Viewed by 2517
Abstract
Driven-pile setup is referred to a phenomenon in which the bearing capacity of driven piles increases with time after the end of driving (EOD). The setup effect can significantly improve the bearing capacity (ultimate resistance) of driven piles after initial installation, especially the [...] Read more.
Driven-pile setup is referred to a phenomenon in which the bearing capacity of driven piles increases with time after the end of driving (EOD). The setup effect can significantly improve the bearing capacity (ultimate resistance) of driven piles after initial installation, especially the ultimate shaft resistance. Based on the reliability theory and considering the setup effects of driven piles, this article presents an increase factor (Msetup) for the ultimate resistance of driven piles to modify the reliability index calculation formula. At the same time, the correlation between R0 and Rsetup is comprehensively considered in the reliability index calculation. Next, the uncertainty analysis of load and resistance is conducted to determine the ranges of relevant parameters. Meanwhile, the influence of four critical parameters (factor of safety FOS, the ratio of dead load to live load ρ = QD/QL, Msetup, the correlation coefficient between R0 and Rsetup, and ρR0,Rsetup) on reliability index are analyzed. This parametric study indicates that ρ has a slight influence on the reliability index. However, the reliability index is significantly influenced by FOS, Msetup, and ρR0,Rsetup. Finally, by comparisons with the existing results, it is concluded that the formula proposed in this study is reasonable, and more uncertainties are considered to make the calculated reliability index closer to a practical engineering application. The presented formula clearly expresses the incorporation of the pile setup effect into reliability index calculation, and it is conducive to improving the prediction accuracy of the design capacity of driven piles. Therefore, the reliability analysis of driven piles considering setup effects will present a theoretical basis for the application of driven piles in engineering practice. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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15 pages, 3198 KiB  
Article
Field Tests on Bearing Characteristics of Large-Diameter Combined Tip-and-Side Post Grouted Drilled Shafts
by Zhitong Zhang, Weiming Gong, Guoliang Dai, Xiaolin Cao, Yu Zhu and Hao Huang
Appl. Sci. 2021, 11(24), 11883; https://doi.org/10.3390/app112411883 - 14 Dec 2021
Cited by 5 | Viewed by 1609
Abstract
This paper presents a field study on the axial behavior of four large-diameter drilled shafts embedded in coarse sand. The grouting and loading test procedures were reported. The bearing capacity of shafts (TS1 and TS2) and grouted drilled shafts (TS3 and TS4) were [...] Read more.
This paper presents a field study on the axial behavior of four large-diameter drilled shafts embedded in coarse sand. The grouting and loading test procedures were reported. The bearing capacity of shafts (TS1 and TS2) and grouted drilled shafts (TS3 and TS4) were herein determined by the bi-directional static test and top-down load test, respectively. The enhancement mechanism of bearing characteristics of the grouted shafts was discussed in detail. The test results indicate that the bearing characteristics and load transfer mechanisms of the test shafts were significantly affected by the quantity of pressurized cement slurry and the mechanical properties of the soil surrounding the shafts. Furthermore, the tip resistance of shaft can be mobilized more rapidly and fully after grouting, the side and tip resistance are mobilized in a more synchronized and coordinated manner due to the pre-mobilization of the grouted cement. Additionally, the standard penetration test (SPT) prediction model was introduced to calculate and predict the SPT blow counts of soil after grouting. The results show that the post grouting has a more obvious improvement on the strength of cohesionless soil. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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12 pages, 24972 KiB  
Article
Estimating CPT Parameters at Unsampled Locations Based on Kriging Interpolation Method
by Jinhao Liu, Jinming Liu, Zhongwei Li, Xiaoyu Hou and Guoliang Dai
Appl. Sci. 2021, 11(23), 11264; https://doi.org/10.3390/app112311264 - 29 Nov 2021
Cited by 5 | Viewed by 2289
Abstract
The cone penetrometer test (CPT) has been widely used in geotechnical investigations. However, how to use the limited CPT data to reasonably predict the soil parameters of the unsampled regions remains a challenge. In the present study, we adopted the Kriging method to [...] Read more.
The cone penetrometer test (CPT) has been widely used in geotechnical investigations. However, how to use the limited CPT data to reasonably predict the soil parameters of the unsampled regions remains a challenge. In the present study, we adopted the Kriging method to obtain the CPT data of an unsampled location in Adelaide, South Australia, based on the collected CPT data from six soundings around this location. Interpolation results showed that the trend of the estimated parameters is consistent with the trend of parameters of the surrounding points. From the Kriging interpolation result, we further carried out axial bearing capacity calculation of a precast concrete pile using the CPT-based direct method to verify the reliability of the method. The calculated bearing capacity of the pile is 99.6 kN which is very close to the true value of 102.8 kN. Our results demonstrated the effectiveness of the Kriging method in considering the soil spatial variability and predicting soil parameters, which is quite suitable for the application in engineering practice. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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14 pages, 987 KiB  
Article
Prediction of Ultimate Bearing Capacity of Shallow Foundations on Cohesionless Soils: A Gaussian Process Regression Approach
by Mahmood Ahmad, Feezan Ahmad, Piotr Wróblewski, Ramez A. Al-Mansob, Piotr Olczak, Paweł Kamiński, Muhammad Safdar and Partab Rai
Appl. Sci. 2021, 11(21), 10317; https://doi.org/10.3390/app112110317 - 3 Nov 2021
Cited by 34 | Viewed by 3426
Abstract
This study examines the potential of the soft computing technique—namely, Gaussian process regression (GPR), to predict the ultimate bearing capacity (UBC) of cohesionless soils beneath shallow foundations. The inputs of the model are width of footing (B), depth of footing ( [...] Read more.
This study examines the potential of the soft computing technique—namely, Gaussian process regression (GPR), to predict the ultimate bearing capacity (UBC) of cohesionless soils beneath shallow foundations. The inputs of the model are width of footing (B), depth of footing (D), footing geometry (L/B), unit weight of sand (γ), and internal friction angle (ϕ). The results of the present model were compared with those obtained by two theoretical approaches reported in the literature. The statistical evaluation of results shows that the presently applied paradigm is better than the theoretical approaches and is competing well for the prediction of UBC (qu). This study shows that the developed GPR is a robust model for the qu prediction of shallow foundations on cohesionless soil. Sensitivity analysis was also carried out to determine the effect of each input parameter. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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16 pages, 5990 KiB  
Article
Experimental Evaluation of the Bending Behavior of a Drilled Shaft with Partial Casing under Lateral Loads
by Xiaojuan Li, Guoliang Dai, Xueying Yang, Qian Yin, Wenbo Zhu and Fan Zhang
Appl. Sci. 2021, 11(20), 9469; https://doi.org/10.3390/app11209469 - 12 Oct 2021
Viewed by 2044
Abstract
Few studies, especially those related to field tests, have examined the bending behaviors of drilled shafts with partial casings (DSPCs). This work reports the results of experimental studies on the behavior of DSPCs under lateral loads, including an in situ test and a [...] Read more.
Few studies, especially those related to field tests, have examined the bending behaviors of drilled shafts with partial casings (DSPCs). This work reports the results of experimental studies on the behavior of DSPCs under lateral loads, including an in situ test and a set of laboratory tests. First, a DSPC with a diameter of 2 m and length of 87.9 m was studied in clay beds, and a steel casing with a diameter of 2.0 m and length of 33 m was used. In this test, strain gauges were distributed along the steel rebars in the concrete pile and the wall of the steel tube at different depths, and thus the longitudinal strains of the concrete pile and the steel tube could be studied. Second, laboratory experiments were implemented with reinforced concrete-filled steel tubular columns under pure bending conditions. In these tests, strain gauges were distributed along the steel rebars in the concrete pile and the walls of the steel tubes at the pure bending section of the specimens. Different wall thicknesses and drilling fluid conditions were considered. The field test results show that the strain of the concrete piles and the steel tubes were linearly distributed at the same cross-section. This means that a DSPC remains a flat plane after it deforms. Whereas a correction coefficient related to the loading level need to be considered in the calculation of the bending stiffness. Laboratory studies show that the strain of DSPCs was linearly distributed at a small bending moment under the best bond-quality condition, whereas obvious nonlinear behaviors were shown under a large bending moment with poor bond-quality conditions. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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17 pages, 7285 KiB  
Article
Bearing Capacity of Single Pile-Friction Wheel Composite Foundation on Sand-over-Clay Deposit under V-H-M Combined Loadings
by Yikang Wang, Xinjun Zou and Jianfeng Hu
Appl. Sci. 2021, 11(20), 9446; https://doi.org/10.3390/app11209446 - 12 Oct 2021
Cited by 15 | Viewed by 2855
Abstract
This paper presents numerical modelling to investigate the bearing capacities and failure mechanisms of single pile-friction wheel composite foundation in sand-overlying-clay soil conditions under combined V-H-M (vertical-horizontal-moment) loadings. A series of detailed numerical models, with validations of centrifuge testing [...] Read more.
This paper presents numerical modelling to investigate the bearing capacities and failure mechanisms of single pile-friction wheel composite foundation in sand-overlying-clay soil conditions under combined V-H-M (vertical-horizontal-moment) loadings. A series of detailed numerical models, with validations of centrifuge testing results, are generated to explore the potential factors influencing the bearing capacity of this composite system. Intensive parametric study is then performed to quantify the influences of the foundation geometry, soil properties, sand layer thickness, pre-vertical loading and lateral loading height on the failure envelopes in the V-H-M domain. Last but not least, an empirical design procedure is proposed based on a parametric study to predict the bearing capacity of this composite foundation under various loading conditions, which can provide guidance for its design and application. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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18 pages, 20617 KiB  
Article
Study on Soil Displacement Fields around the Expanded Body of Drill-Expanded Concrete Piles Based on DIC Technique
by Lina Xu, Haoyun Deng, Lei Niu, Yongmei Qian and Daohan Song
Appl. Sci. 2021, 11(19), 9097; https://doi.org/10.3390/app11199097 - 29 Sep 2021
Cited by 3 | Viewed by 2273
Abstract
The soil displacement field around a drill-expanded concrete pile is noticeably different from that of an equivalent section pile placed under axial load due to the mutual embedment between the expanded body and the soil. It is important to study the soil displacement [...] Read more.
The soil displacement field around a drill-expanded concrete pile is noticeably different from that of an equivalent section pile placed under axial load due to the mutual embedment between the expanded body and the soil. It is important to study the soil displacement field around drill-expanded concrete piles in order to understand the mechanisms of interaction between the pile and the soil. First, the model test of the half-face pile installed in undisturbed soil and the model test of the half-face pile installed in sand were used to study the soil displacement field around the pile. Then, the entire process of the soil displacement field’s formation and development under the load was observed by using digital image correlation (DIC) techniques. Finally, numerical simulation was used to verify the results of the model tests. The results show that the displacement characteristics of the soil around the pile in the undisturbed soil and sand are basically the same. There is a clear soil compression zone under the expanded body, and the magnitude and density of the displaced soil in the compression zone are much higher than in other areas. Both the vertical displacement and the horizontal displacement gradually decrease as the distance from the expanded body and the burial depth increase. The horizontal displacement of the soil under the expanded body follows a trend of first moving toward the pile body and then moving away from it. The results of the numerical simulation are basically consistent with the results of the model test, indicating that the results of the model test are relatively reliable. Full article
(This article belongs to the Special Issue Recent Progress on Advanced Foundation Engineering)
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