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A study was undertaken to evaluate the embodied greenhouse gas emissions of four different design options for the foundation of a residential modular building in the East Midlands, UK. The assessment considered the embodied carbon dioxide equivalent of material production (without and with Portland cement replacement using ground granulated blast-furnace slag), transportation, construction works (such as soil excavation) and plant usage on site and off site. The findings indicated that helical piles and reinforced concrete slabs supported with expanded polystyrene were the most sustainable options (in terms of embodied emissions) compared with conventional strip and pad foundations. This study provides valuable insight into considerations and constraints that may arise when evaluating the sustainability of modular building foundations. It offers practical guidance for decision makers in the modular construction sector seeking to mitigate the environmental impact of their geotechnical design. [ABSTRACT FROM AUTHOR]

The identification and repair of structural damage in building foundations are critical tasks in ensuring the safety and integrity of civil infrastructure. This research paper proposes a method based on genetic algorithms for the identification and repair of structural damage in building foundations. The proposed approach begins with the identification of structural damage by analysing sensor data, including vibration measurements and strain gauges, obtained from the building's foundation. A genetic algorithm is then employed to optimize the identification process by iteratively searching for the most likely damage scenarios based on the collected sensor data. Once the damage is identified, the algorithm proceeds to develop an optimal repair strategy. It considers various parameters, such as available repair materials, budget constraints, and desired structural performance, to generate a repair plan that minimizes cost and maximizes the restoration of structural integrity. The repair plan is optimized using the genetic algorithm to find the best combination of repair techniques and materials. To evaluate the effectiveness of the proposed method, extensive simulations and case studies are conducted on different types of building foundations. The performance of the algorithm is assessed in terms of its accuracy in identifying structural damage and the efficiency of the repair strategy. [ABSTRACT FROM AUTHOR]

Abstract Coastal civil infrastructure is vulnerable to the effects of climate change. Hurricane storm surge and coastal flooding can cause significant hydrostatic and hydrodynamic loads on structures while saltwater intrusion (SWI) may lead to deterioration of foundations. The effects of saltwater intrusion due to Sea Level Rise (SLR) on the foundations of buildings and other civil infrastructure is poorly understood. Such damages may not be detected in a timely fashion nor be insured, leading to significant and unanticipated expenses for building owners. In this study, we evaluate the impact of SWI due to various SLR scenarios on the corrosion of reinforcement in foundations of nearly 137,000 residential buildings in low-lying areas surrounding Mobile Bay, AL. We find that the potential for costly damage is significant. Under an extreme SLR scenario, the annual expected repair costs for the foundations of the studied homes may reach as much as US$90 million by 2100.

This work presents an analytical method for determining vertical dynamic impedance and displacement response factor of a rigid cylindrical foundation embedded in unsaturated poroelastic soils. The foundation is assumed to be perfectly boned to its surrounding soil and its overlying half-space of unsaturated poroelastic soil, subjected to harmonic vertical loadings. The soil surrounding the circumference of the cylinder is modeled as a number of infinitely thin horizontal soil layers. Based on the Biot-type soil constitutive model, the equations governing the interaction of unsaturated soils with the cylindrical foundation are derived. Solutions are obtained by solving ordinary differential equations transformed from partial differential governing equations using the Hankel transform. The proposed solutions are verified against existing solutions of benchmark elastodynamic problems for embedded cylindrical foundations in dry and saturated soils. Using the derived solutions, several influencing parameters defining the stiffness and mass of the foundation system are examined to investigate the dynamics of the foundation interacting with it adjacent soils. It is concluded that the dynamic displacement response factor is sensitive to soil saturation. It is believed that the proposed solution should be beneficial to dynamic design with cylindrical foundations embedded in unsaturated soils. [ABSTRACT FROM AUTHOR]

In soft soil layers, piles are frequently loaded laterally by horizontal soil movements. In many cases, the lateral pressure acting on piles due to horizontal soil movements is calculated with empirically or analytically based approaches, respectively. However, most of these design approaches do not consider possible influences on the resulting pile loads. This paper presents the results of model tests and numerical simulations on single piles and pile groups in cohesive soil subjected to lateral loads which were carried out to overcome limitations of available design approaches. Based on extensive small-scale 1 × g-model tests and numerical investigations with the finite element method, influencing factors on the lateral pressure, such as the roughness of the pile–soil interface, the pile size, the pile shape and the pile spacing were identified. A parametric study with the numerical model quantified the most relevant factors influencing the development of lateral pressure on piles due to adjacent surface loads and lead to the development of a simplified analysis approach. [ABSTRACT FROM AUTHOR]

In the realm of constructing urban underground spaces, it is imperative to address the impact of tunnel leakage on the surrounding environment. This paper introduced a theoretical analysis to investigate the localized water leakage's influence on adjacent pile foundations. A pore pressure distribution function, accounting for localized leakage water, was formulated. Integrated with the seepage control equation, this function facilitated the calculation of additional stress imposed on piles due to tunnel localized water leakage. Employing the Pasternak foundation model, an analytical solution was developed to assess the lateral performance of adjacent piles under localized water leakage conditions. This approach was compared with numerical simulations to validate the reliability of soil seepage fields and pile lateral performance resulting from localized tunnel leakage at different positions. Through comprehensive parameter analysis, it was observed that the width of the leakage joint significantly influenced pile lateral responses, manifesting in three distinct stages: linear increase, nonlinear gradual augmentation, and stabilization. Different positions of the lining leakage joint yielded varying effects on adjacent piles' lateral responses, with closer proximity intensifying the impact on the pile. When leakage joints were situated near the pile toe, a pronounced negative bending moment was generated. Furthermore, this study summarized the influence range of tunnel localized leakage adjacent to piles. It established that the maximum pile-tunnel horizontal distance inducing lateral pile responses due to tunnel localized leakage was set at 8 times the pile diameter (8 Dp). Additionally, tunnel leakage influences should be considered when the pile length exceeded 0.6 times the depth of the tunnel axis. [ABSTRACT FROM AUTHOR]

Seasonal freeze–thaw (F–T) cycles significantly affect the mechanical properties of soils and the behavior of pile foundations in soils subjected to F–T cycles under different loading conditions. Soils exposed to F–T cycles can impact the performance of pile foundations. Consequently, the effects of F–T cycles should be taken into account when designing piles, particularly in cold regions such as Canada. In recent years, climatic conditions in Canada have changed due to global warming, increasing the number of F–T cycles in many regions each year. This study aimed to investigate the influence of different numbers of F–T cycles on the behavior of piles in sandy soils. Laboratory experiments were conducted on physical models of piles subjected to axial (uplift) and lateral loads combined with F–T cycles. The model was scaled using standard scaling principles, and the test apparatus was equipped with various sensors to measure temperatures, forces, and displacements. The results showed that as the number of F–T cycles increased, the lateral capacities of the piles under individual and combined loads increased steadily. The lateral load capacity increased from 350 to 430 N after five F–T cycles under individual loading and from 225 to 455 N after five F–T cycles under combined loading. However, the pile's uplift load capacity remained constant under individual and combined loads and there was no change due to F–T cycles. The results of this experimental study will be useful for understanding the behavior of piles subjected to seasonal F–T cycles and for improving the design of pile foundations in cold regions. [ABSTRACT FROM AUTHOR]

Under various stress paths, the deformation characteristics represented great differences. In this paper, a series of cyclic triaxial tests have been conducted with Fujian standard sand. By comparing the constant deviatoric (CDS) and constant axial stress paths (CAS), the influence mechanism of the cyclic amplitude of the deviatoric stress was discussed. The test results showed that the stress path significantly influenced the volumetric and shear strains. The increasing and decreasing trend in the volumetric strain (ɛv) was consistent with the spherical stress (lnp). Compared with the two stress paths, the slope of the ɛv−lnp curve during the loading and unloading stages was larger under the CAS path. In the CDS path, qc almost did not affect the cumulative volumetric strain, and in the CAS path, the effect was obvious. The shear strain curve was in accordance with the direction of the stress path. As the cyclic number increased, the shear strain gradually accumulated. The shear strain accumulation under the CAS path was larger. The shear strain largely depended on the relative position between the critical state line (CSL) and the stress state of the soil during cyclic loading and unloading. Practical Applications: In practical engineering, the soil will experience various stress paths. For example, in slope or earth–rock dam engineering, where the water level rises and falls repeatedly, the soil often goes through the stress path of constant deviational stress with the cyclic increase and decrease in the spherical stress. In foundation pit engineering, the soil often experiences the stress path of the constant axial stress (CAS) with cyclic loading and unloading of the lateral stress. The stress path greatly influences the deformation and strength of soil. Therefore, the previous two stress paths are compared in this paper to discuss the influence of the cyclic amplitude of deviatoric stress. Under three different consolidation states, the cyclic amplitude of the deviatoric stress significantly influenced the volumetric and shear strains. The shear strain largely depended on the relative position between the critical state line (CSL) and the stress state of the soil during cyclic loading and unloading. Therefore, in practical engineering, if the stress path in the experiment differs from the actual value, the influence of the stress path should be properly considered. The results should be modified according to the degree of influence of each stress condition. [ABSTRACT FROM AUTHOR]

Collapsibility significantly impacts the bearing capacity of pile foundations in loess areas. To improve the load-bearing capacity of piles, the pile-base postgrouting technique is widely used worldwide. However, there are still several related issues to be solved: the impact of loess collapsibility on the bearing capacity; the effectiveness of the pile-base postgrouting technique in enhancing the bearing capacity; and the diffusion pattern of the grout during the grouting process. To investigate these issues, this experiment utilizes a visual static pressure device combined with numerical simulation. According to the experiment, the maximum axial force and neutral point appeared to shift downward after grouting, resulting in a 17.5% increase in the bearing capacity of the pile foundation. Additionally, an increase in grouting pressure leads to a rise in both the number of shear cracks and the diffusion radius. As the permeability of the grout improves, the number of shear cracks and diffusion radii tend to stabilize after an initial increase. These discoveries enable a thorough analysis of the changes in side friction and base resistance of postgrouted piles in collapsible loess. Furthermore, they provide valuable references and guidance for the implementation of the pile-base postgrouting technique in loess areas. [ABSTRACT FROM AUTHOR]

The prevailing design methodology for foundation pit support structures conventionally treats the pit cross section as a two-dimensional plane, facilitating the computation of soil and water pressures acting upon the retaining structure. Regrettably, this conventional approach tends to overlook the critical corner effect, particularly when the foundation pit is in proximity to a subway tunnel, where the nuanced nature of this corner effect remains indeterminate. Consequently, this research is directed toward an in-depth investigation of a deep foundation pit contiguous to a subway tunnel. A systematic evaluation and optimization of the corner effect pertaining to the deep foundation pit are undertaken through a combination of comprehensive field monitoring and simulation methodologies. The results show that a substantial mitigation in the deformation of the supporting structure, settlements of the ground surface and adjacent buildings, as well as the displacement of the subway tunnel, were achieved through a consideration of the corner effect. Notably, the ameliorative impact of adjacent buildings on the corner effect is observed. Further scrutiny reveals that the supporting structure within a distance of 12 m from the pit corner is most susceptible to the corner effect, as evidenced by a plane strain ratio (PSR) falling below 0.8. Beyond a spatial threshold of 20 m, the PSR attains a value of 1.0, indicative of a negligible corner effect and the foundation pit section existing in a plane strain state. The adjustment of pile length or diameter based on the PSR emerges as a viable strategy that can realize the construction cost optimization on the premise of ensuring the stability of the foundation pit. The impact of pile diameter variation is paramount, corresponding to a reduction in the range of PSR values below 0.8 from 12 m to 9.8 m. The corner effect is significantly diminished. [ABSTRACT FROM AUTHOR]

In recent years, foundation pit construction has been rapidly developing in the direction of deep and large-scale, leading to the frequent occurrence of construction accidents. The pit construction process is characterised by a complex environment, high construction risk, and numerous coupling effects between the construction risk factors. In this paper, 23 main accident-causing factors in foundation pit construction are determined based on the six major risk accident types. In addition, the Grey-DEMATEL-Fuzzy comprehensive evaluation method of the risk evaluation model is introduced for better prediction and judgment of risk level, which combines the grey system theory with the method of decision-making experimental analysis, and in the case of inaccurate or incomplete information, the use of less data can achieve the evaluation results with a high degree of reliability, and it will effectively avoid the impact of the lack of information as well as the subjectivity in the process of risk evaluation. Through the Grey-DEMATEL method, the central degree value for each risk indicator factor is calculated, the coupling role and importance of each risk indicator are analysed, and the indicator weights are calculated. Based on the calculated weights, the fuzzy comprehensive evaluation method is used to evaluate the overall risk level. The empirical research on the deep foundation pit construction project of Haitangxi subway station in Chongqing reveals that the excessive lateral earth pressure on the pile wall is the most prominent risk factor. The overall risk level of the construction process is medium, and the risk is within the controllable range. On this basis, corresponding preventive measures can be formulated, providing a basis for risk prevention in the construction of deep foundation pit projects. [ABSTRACT FROM AUTHOR]

Translation abstract Induced vibrations of structures on piled or shallow foundations – a comparison using numeric calculationsWhen predicting structural vibrations due to vibration sources in the neighbourhood, e. g. from traffic, construction work or machine vibrations, the question sometimes arises as to what influence the foundation of the structure has on the amplitude and frequency content of the resulting vibrations. This article systematically compares the so‐called induced vibrations of structures on pile foundations and on shallow foundations on the basis of numerical calculations. After a description of the calculation method using the “Thin Layer Method” (TLM) in the frequency domain, individual piles in a homogeneous half‐space and those in a soil layer on a stiffer subsoil are first considered. Excited by horizontal and vertical forces on the ground surface at some distance, the amplitudes of the vibration velocity (Schwingschnelle) at the level of the pile head before and after installation of the pile are determined and compared. Frequencies between 1 Hz and 40 Hz are considered. The influence of soil stratification is discussed. In the second part of the work, the vibration velocities of shallow and pile foundations under the same excitation are calculated and compared. Characteristic differences can be recognized from the comparison. In this analysis the rising building structures are modelled as rigid masses in a highly simplified manner. The calculation results contribute to the introductory question. [ABSTRACT FROM AUTHOR]

AbstractNowadays, the use of deep foundations in various civil engineering projects, especially in marine and coastal structures, has been increasing. One type of deep foundations are helical pile foundations, which have gained significant attention in recent decades. This research investigates the load–displacement behavior of different helical pile configurations regarding geometry, i.e., helix diameter and spacing ratio (S/D) in two different soil densities under pullout and compressive loading conditions via the FCV-AUT device. Babolsar sand from the southern coast of the Caspian Sea was utilized for advancing this study. Additionally, four full-scale pile tests were conducted on the Caspian Sea coast under both grouted and non-grouted conditions for pullout and compressive loading. The results indicate that increasing the helix diameter, soil density, and S/D ratio enhances the compressive load-bearing capacity. However, in tensile loading, the ultimate load decreases with an increase in the spacing ratio. Furthermore, the grouting process in the three-helix pile exhibits better performance compared to the two-helix pile, potentially increasing the pile capacity up to 30%. In conclusion, the results obtained from the FCV device, utilizing scale theory, have been generalized to the large-scale pile test results in the field, are representative of in agreement and compatible. [ABSTRACT FROM AUTHOR]

Translation abstract Innovative foundation for noise barriers – a Deutsche Bahn pilot project with ground screwsIn geotechnical engineering, ground screws are often associated with lightweight constructions and are established worldwide as a foundation for solar power plants. Larger ground screw designs are currently being developed and tested as part of pilot projects. At approx. 406 mm, these ground screws have around four times the tube diameter of the above mentioned and are therefore to be classified and dimensioned as pile foundations. In contrast to conventional driven steel piles, the ground screws are driven into the ground without vibration. It is obvious that the foundation elements should be used where particular attention must be paid to noise and vibration emissions. For example, as a foundation element for noise barriers as part of the special noise remediation program for the Middle Rhine Valley. This article presents the Deutsche Bahn pilot project, provides information on the design of the large ground screws and highlights the advantages of the innovative foundation system. [ABSTRACT FROM AUTHOR]

The joints between precast reinforced concrete pile segments in deep foundations are typically mechanically lockable. They include anchor bars embedded inside the ends of each segment, forming lap splices with the main bars. Because of their particular technology, these lap splices are somewhat different from traditional lap splices, as shown in the first part of this paper, where the impact of their specific characteristics on the tensile behavior of the joints is discussed. The experimental section presents the results of 19 tensile tests on these lap splices and compares them with established theoretical models. The roles of various parameters (lap length, type and amount of confining reinforcement, type of anchor bars, and concrete cover thickness) are investigated. One of the major findings indicates a significantly lower lap capacity when using plain‐bar spirals compared to closed‐ribbed stirrups. Additionally, at low stress levels, the models tend to be unconservative. Building on this insight, a modified model is proposed for lap splices provided with plain‐bar spirals. [ABSTRACT FROM AUTHOR]

In this study, numerical analyses of connected and disconnected piled-raft foundations (PRFs) comprising a single pile, 2 × 1, 3 × 1, 2 × 2, 3 × 2, 3 × 3 and 5 × 5 pile groups subjected to different lateral loads, with a constant vertical load, have been carried out by three-dimensional finite-element analysis. Results from the analysis have been validated with reported field studies considering vertical load and reported experimental studies considering lateral load. The reported multilayered sub-soil profile has been considered for the analysis. Parametric studies in terms of the effect of variation in pile length (L/d = 20, 30, 39), spacing of piles in the pile group (S/d = 3, 5, 6), number of piles, thickness of raft (0.5, 1.2 and 2 m), variation of axial force, excess pore water pressure, bending moment and shear force along the depth of the piles for connected and disconnected PRFs have been discussed for a time period of 20 years. The horizontal connected piled-raft coefficients have been determined corresponding to the lateral deflections. A generalised equation has been predicted for the horizontal connected PRF coefficient. [ABSTRACT FROM AUTHOR]

The PHC (pre-stressed high-strength concrete) pile foundation, serving as an innovative supporting structure for solar power stations, is subjected to complex loading conditions in engineering scenarios. In this study, field tests of the full-scale PHC Pile foundation were conducted in sand layer, loess layer, and double-layer sites to investigate its operational behavior under different load conditions. The study assessed the inclination of the column top, ground displacement, and torsion to analyze the stress and deformation characteristics of PHC pile foundations. The deformation of PHC short pile foundations exhibited distinct phases. Torsional load reduced the column crack load by 30%. The pile cap effectively controlled plastic deformation, minimizing foundation deformation, while torsional load increased lateral deformation. Under cyclic load, the PHC pile behaved with an approximate elasticity characteristic within the test load range. The deformation increased by approximately 10%. Furthermore, three-dimensional numerical simulations analyzed the effects of foundation dimension, bending-moment-to-lateral-load ratio, torque-to-lateral-load ratio, and pile cap size on internal forces and deformation. Simulations indicated that increasing the pile cap length was more advantageous for reducing deformation and internal forces. The bending-moment-to-lateral-load ratio was significant in design, while the torque-to-lateral-load ratio had a negligible impact. A comprehensive design program is proposed based on field tests and numerical simulations, considering deformation and bearing capacity. The study confirms the reliability of the PHC pile foundation as a support structure for heliostats, aiming to offer valuable insights for practical applications. [ABSTRACT FROM AUTHOR]

Piled raft foundations (PRFs) below stepped high rise towers are often subjected to non-uniform loads with eccentricities. In this study, twenty five cases of rectangular rafts with different pile configurations and orientations embedded in sand are analyzed using nonlinear three-dimensional finite element analysis. These PRFs are subjected to different triangularly distributed loads and uniformly distributed loads with and without eccentricities. The piled raft responses investigated are the maximum and differential settlements, angular distortion, tilt, load sharing between the raft and the piles, the load carried by the individual piles, and the subgrade modulus (spring constant) at the raft-soil and pile-soil interfaces. The PRF responses are greatly influenced by the distribution of the applied loads and the magnitudes of the load eccentricities. The study provides insights into the PRF behavior under nonuniform and eccentric loads and may help practitioners in making informed design decisions. [ABSTRACT FROM AUTHOR]

Pile foundations supporting wind turbines, silos, elevated water tanks or bridge piers are frequently subjected to multi-component loads, which may lead to significant rotations and settlements compromising the safe operation of the structure. The prediction of these displacements is of major concern and can be easily carried out using force-resultants plasticity models, also referred to as 'macro-elements', stemming from the idea of describing the foundation behaviour by a single upscaled constitutive relationship between generalized forces and displacements. When properly formulated, they can reproduce key aspects of the mechanical response of the foundation at low computational cost as compared to numerical analysis. To this end, a new macro-element for pile groups formulated in the classical framework of strain-hardening elasto-plasticity is presented and discussed. The required model parameters can be calibrated by closed-form equations and additional few data of numerical and/or experimental nature. The proposed mathematical framework is finally validated against the results of centrifuge tests and 3D finite element analyses. [ABSTRACT FROM AUTHOR]

Records of pile lengths are not available for several hundred high-mast light towers (HMLTs) throughout the state of Minnesota. The foundation systems, typically steel H-piles or concrete-filled steel pipe piles connected to a triangular concrete pile cap, risk overturning in the event of peak wind loadings if the foundation piles are not sufficiently deep to provide the designed uplift capacity. Without prior knowledge of the in situ pile lengths, an expensive tower foundation retrofit or replacement effort would need to be undertaken. However, the development of a nondestructive screening tool to determine the in situ pile length—compared with replacing or retrofitting all towers with unknown foundation geometries—would potentially provide significant cost savings. The main goal of the research is the development of nondestructive evaluation testing techniques for determining in situ pile lengths using steady-state vibration and hammer-impact seismic testing. The foundation testing protocol involves (1) a preliminary site investigation to determine the shallow subsurface geometry and orientation of the foundation pile cap, (2) the use of seismic cone penetrometer (SCP) attached to a cone penetration test rig to capture the induced steady-state and impact waveforms, and (3) data-driven analysis of field testing results to determine the pile lengths. [ABSTRACT FROM AUTHOR]

In order to solve the problem of poor accuracy of blasting vibration prediction by the traditional Sadowski empirical formula and BP neural network, a model based on the mind evolutionary algorithm (MEA) is proposed for the first time to optimize the BP neural network. The blasting demolition of a raft slab foundation of an underground garage in Shenyang City, Liaoning Province, China, is taken as a research object, and the effects of the horizontal distance between different monitoring points, demolition area, elevation difference, the maximum amount of a single section of the charge, and the horizontal angle between the measurement point and the minimum resistance line on the peak velocity of vibration are taken into account. The empirical Sadowski formula, the MEA-BP algorithm, and the GA-BP algorithm were introduced to randomly train the 40 sets of data monitored at the site and to predict the eight sets of data outside the training, respectively. The results showed that the maximum relative errors of the results predicted by the MEA-BP model, the GA-BP model, and the empirical Sadowski formula were 14.94%, 19.36%, and 22.81%, respectively, and the average relative errors were 8.88%, 10.79%, and 16.84%, respectively. The prediction results corroborate that the MEA-BP algorithm has high adaptability in blasting vibration prediction for raft foundation demolition and provides reference for the prediction of vibration peak velocity in similar blasting projects. [ABSTRACT FROM AUTHOR]

Piled rafts and pile groups are the common types of deep foundations for tall buildings subjected to combined loading. Their complex behavior made their design and analysis very complex and sometimes uneconomical. This paper explores the distribution of lateral load on piles within a piled raft and pile group under a constant vertical load. The study utilized experiments with small-scale models of piles and rafts to observe the behavior. The response of each pile was recorded and analyzed with respect to lateral displacement. The results indicated that in the case of piled rafts under lateral load, the rear piles are resisting more load than the front piles, unlike in pile groups where front piles carry more load than rear piles. This behavior continued until the number of piles reaches nine, thereafter the load-carrying behavior shifted, and front piles began to carry more lateral load. The reason behind this shift is that as the number of piles increases, the raft contact pressure decreases and subsequently decreases the stiffness of soil below raft and hence the piled raft starts behaving as a pile group, where front piles carry more lateral load. [ABSTRACT FROM AUTHOR]

Previous earthquake events indicate that pile foundations in liquefiable soils are vulnerable to damage due to the coupling of inertial and kinematic effects. Inclined piles are widely applied in structures located in liquefiable soils, but few investigations of the coupling of the superstructure–pile inertial and soil–pile kinematic effects have been conducted. To address this gap, this study adopted a three-dimensional (3D) numerical model to investigate the coupling of inertial and kinematic effects in pile foundations with different inclination angles. The pile head bending moment was employed to represent the pile response, while the soil surface displacement and structure acceleration were utilized to quantify the kinematic and inertial effects. The role of the inclination angle on the interactions between inertial and kinematic effects is herein considered for pile groups. In particular, the inertial effect significantly influences the behavior of pile groups with larger inclination angles, whereas the kinematic effect predominates the pile head moment in vertical pile groups. In this paper, the influence of the pile inclination angle, superstructure configuration, and earthquake intensity on the interactions was investigated. The principal findings revealed that the kinematic effect dominates in the vertical pile group irrespective of the properties of the superstructure, while the inertial effect plays a significant role in the response of the inclined pile groups, especially for superstructures with considerable heights. Practical Applications: Inclined piles are vulnerable to damage due to the interaction of inertial and kinematic effects during earthquakes. This study conducted a series of three-dimensional (3D) finite-element simulations to investigate the interaction of inertial and kinematic effects in pile foundations with different inclination angles. The influence of pile inclination angle, superstructure height, and earthquake characteristics was investigated. In current practices, various codes and pseudostatic methods have been adopted to sum a percentage of the inertia-induced bending moment and another percentage of the kinematic-induced bending moment. This study indicates that under certain conditions, the simple summing of the bending moment induced by the inertial and kinematic effects could be inaccurate. The present study identified several factors that influence the interaction of inertial and kinematic effects on piles with different inclination angles. The inclined piles in liquefied soil, especially for supporting tall and heavy superstructure, attention should be given to the influence of inertial effect on the pile head bending moment. [ABSTRACT FROM AUTHOR]

When the drilling and blasting method is used to excavate urban subway tunnels, the blasting seismic waves will inevitably produce vibration effects on the pile foundations under the surface buildings, which will seriously threaten the safety of surrounding buildings and the environment. Based on the transmission and reflection laws of stress waves at the interface between soil medium and pile medium and the displacement–stress continuous assumption, the wave function expansion method is used to analyze the whole process mechanism of vibration effect of hollow pipe piles under the action of incident P waves. In addition, the theoretical model of safety criterion for hollow pipe piles under blasting vibration is proposed and the reliability of the model is verified. Furthermore, the impacts of the elastic modulus, density, and pile section parameters of soil and piles on the safety criterion for the blasting vibration effect of hollow pipe piles are analyzed. The results show that as the elastic modulus and density of the soil increase, the critical peak particle velocity (PPV) curves of hollow pipe piles move to the high-frequency and low-frequency bands, respectively, resulting in a decrease in the overall safety of piles. This indicates that hollow pipe piles should not be buried in soil layers with high elastic modulus and density. It is also shown that the larger the hollow area of hollow pipe piles, the lower their safety. Compared to solid circular piles, hollow pipe piles have a higher overall seismic safety reserve. The study results have guidance and reference value for effectively evaluating and controlling the harm of blasting vibration effects of hollow pipe piles. [ABSTRACT FROM AUTHOR]

Translation abstract Index tests to determine the abrasiveness of soilThe wear of tools can represent a relevant cost factor especially in foundation engineering and tunnelling, which ideally should be predictable before the start of construction. However, various factors need to be considered, such as the wear potential of the soil, tool properties, construction method, execution conditions and other project‐specific factors. The DGGT Working Group 1.11 “Wear and Adhesion” is working on recommendations for assessing the wear potential of soil, among other things. In this context, several index tests have been identified that can be used to determine the abrasiveness of soils, although it should be noted that laboratory results do not always reflect real soil conditions. The presented test methods cover different particle size ranges, and a combination of tests allows for the characterization of the abrasiveness of widely grades and mixed‐graded soils. [ABSTRACT FROM AUTHOR]

Used extensively in structural dynamics analysis, the energy method is advantageous for transforming boundary value problems of differential equations into variational extremum problems. Recent applications include analyzing the wave and vibration characteristics of track structures. However, traditional energy methods for dynamic modeling and analysis of ballastless track structures require obtaining the global stiffness matrix and mass matrix of the entire coupled system, which decreases computational efficiency. The EM-CMS algorithm for frequency domain dynamic response analysis of ballastless track structures has been proposed to address this issue. The core of EM-CMS is the development of model reduction strategies within the framework of the energy method to reduce matrix dimensions and thereby improve computational efficiency. Specifically, the steel spring floating slab track is the focus of this research. Utilizing the energy functional variational method, the modal properties of the rail and floating slab structures are obtained, and truncation is performed. A reduced-order model for the steel spring floating slab track is established by considering the boundary conditions between the rail-floating slab and the floating slab foundation (connected through fastener springs and steel springs, respectively, and considering the springs' elastic potential energy). Comparatively, the computational efficiency of EM-CMS is approximately ten times greater than that of the energy method. The method's accuracy is also carefully validated against finite element simulations. [ABSTRACT FROM AUTHOR]

Excavation of deep and long pits can cause strata deformation and settlement of adjacent buildings. The excavation of a deep foundation pit of a nearby building in Zhengzhou City, China, is taken as the research object. The foundation of the foundation pit is an independent foundation under the column, the depth of the foundation pit is 24.5∼26.3 m, and the support form of an underground continuous wall and four internal supports is adopted. The stress and deformation characteristics of retaining structures during the construction of deep and long pits and their impact on the deformation of nearby buildings were studied through on‐site monitoring and finite element simulation. The analysis focuses on the effects of different excavation stages on adjacent structures, with the main conclusions as follows. After excavation, the underground continuous wall far from the building undergoes a "rotating‐kick" displacement, while the underground continuous wall on the side near the building only shows a "kick" displacement. Adjacent buildings have little influence on the distribution of shear force and bending moment of the underground continuous wall of the foundation pit. The first horizontal strut experiences pressure, gradually shifting to tension as excavation continues, with the maximum stress reaching 3.6 × 103 kN. The second, third, and fourth horizontal struts mainly bear compressive forces, increasing with the depth of the struts. The building primarily undergoes settlement in the early stages of deep and long pit excavation. As the excavation progresses, the building points near the pit begin to bulge, but the building corners far from the pit continue to show settlement. During the excavation of the deep and long pit, the differential settlement of the long side of the nearby building first decreases and then increases, and the differential settlement of the short side changes from a slight decrease to a significant increase. The settlement evolution of the building is as follows: overall settlement ⟶ overall uplift ⟶ uplift of the side of the building near the pit ⟶ outward tilting away from the pit. The findings may provide references for designing, constructing, and operating deep and large foundation pits. [ABSTRACT FROM AUTHOR]

When the pile driving operation of the jacket platform is carried out, the depth of the steel pile into the mud is not enough or the maximum penetration depth of the steel pile is not the expected bearing layer, which will make the bearing capacity of the platform pile foundation insufficient, cause the platform to be unstable and cause safety accidents. In this paper, the energy conservation relationship in the process of pile sinking is analyzed and discussed from the calculation theory of hammering work and internal force work. Combined with the soil data of field engineering, the penetration of pile sinking of jacket platform is calculated and theoretically demonstrated. Through the above in-depth calculation and analysis, the variation law of penetration with formation depth is obtained. Finally, the control suggestions of pile sinking operation of jacket platform are obtained, in order to provide reference for engineering operation. [ABSTRACT FROM AUTHOR]

Pile is a common foundation on the slope, which poses a serious threat to the construction and operation if the slope deformation and causes landslide. In this study, a model device of pile foundation on landslide was independently developed by relative displacement loading between pile and soil to explore the influence of landslide deformation on pile and analysis the soil failure rule and the deformation characteristics of pile in different stages of landslide deformation, a few model tests were completed including the relative displacement between soil and pile from 1 to 17 cm, and the pile diameter and the modulus of slide bed were also considered. The results indicated that: the evolution process of landslide deformation with pile foundation on could be divided into four stages including soil compaction, cracks growth, yield stage, and failure stage; ratios of the maximum soil pressure and bending moment growth from the soil compaction stage to the cracks growth stage to the total growth in these four stages are both exceeding 60%; the soil pressure increases with the increase of pile diameter and sliding bed modulus. Therefore, it is best to effectively monitor and control the landslide in the initial soil compression stage that in soil compaction stage and methods such as increasing pile foundations or reinforcing the sliding bed can be used for protection. [ABSTRACT FROM AUTHOR]

The lateral impact loads induced by blasting excavation of subway tunnel are detrimental to adjacent structures with pile foundations. Physical model tests are carried out to study the dynamic behaviors and failure modes of pile foundations under blasting impact loads. Specifically, the acceleration and strain variation monitoring of friction pile foundations subjected to tunnel blasting is conducted. It is indicated that the bending moment, horizontal acceleration, and dominant frequency (DF) of the pile foundation gradually increase with the standoff distance decrease, while the vibration duration becomes shorter. In the case of pile foundations located in the far field of the explosion, an acceleration amplification effect is observed at the pile top due to the presence of Rayleigh waves (R waves) and the high-frequency filtering effect of the surrounding soil and rock mass. Consequently, the pile-superstructure system experiences resonance, leading to shear failure at the connection between the pile cap and pile top. With decreasing standoff distance, the high-magnitude blasting loads may result in either tensile failure at the pile-soil bond interface or bending failure at the connection. For the pile foundations situated in the near field of the explosion, tensile failure occurs at the pile-soil bond interface, resulting in a loss or failure of the pile's lateral frictional resistance. Alternatively, buckling failure may occur in the middle of the pile, and spalling, cracking failure of concrete occurs at the bottom of the pile. [ABSTRACT FROM AUTHOR]

The paper examines the seismic response of bridge piers, highlighting the essential role of soil-structure interaction (SSI) in enhancing structural resilience. Utilizing MIDAS and LPile software, the study evaluates SSI's impact on bridge pier performance during seismic events. The study involves modeling and analysis under varying soil conditions using MIDAS software. LPile software calculates soil spring stiffness, enabling realistic SSI simulations in MIDAS models. The key objectives include comparison of bridge on deep foundation by analyzing soil properties' effects on SSI, comparing fixed base and SSI models, and providing practical design insights. The findings show significant differences in seismic performance with SSI. The fundamental period increased by 28%, indicating a more flexible response. Maximum displacements in the bridge deck rose by 25% in both X and Y directions, compared to a fixed base model. Additionally, shear forces and bending moments decreased, underscoring SSI's benefits in reducing seismic demands. This study offers valuable insights into bridge structures' dynamic behavior under seismic loading, emphasizing the importance of SSI in seismic design practices. The results are crucial for developing resilient bridge designs capable of withstanding complex SSI during earthquakes. [ABSTRACT FROM AUTHOR]

Pile foundations may be subjected to a combination of vertical and lateral loads that are commonly not applied simultaneously. Model tests of six instrumented single piles embedded in remolded loess, in which self-developed equipment was used to carry out different loading sequences of vertical and lateral loads, were performed. The test results indicate that the preapplied lateral load can cause a decrease in the average skin friction of the pile shaft within 13 times the pile diameter below the ground surface, as well as an increase in the pile end resistance. The settlement of the pile top increases with the increase in the preapplied lateral load, and its rate of change increases with increasing vertical load and increasing preapplied lateral load. With the increase in the preapplied vertical load, both the horizontal displacement of the pile at the measuring point and the maximum bending moment of the pile shaft decrease. The location of the maximum bending moment of the pile shaft is between 2 and 4 times the pile diameter below the ground surface, which approaches the ground surface when the preapplied vertical load increases. The preapplied vertical load can increase the ultimate horizontal bearing capacity of the pile. [ABSTRACT FROM AUTHOR]

Creep deformation and softening of soft soil foundations under long-term wave loading can cause gravity wharves to experience problems such as excessive settlement, displacement, and sliding, compromising the safety of the wharf structure. In this study, we conduct mechanical index and vibration tests on consolidated and undrained soft soil specimens to analyze the changes in the soil dynamic characteristics with strain under different confining pressures. Subsequently, the dynamic deformation and strength characteristics of the soft soil obtained from triaxial tests are used to develop a finite element model of the wave–gravity structure–soft soil foundation system. Using this model, analyses are conducted by varying the friction angle to simulate the change in the soft soil strength as the number of wave cycles increases. The results are evaluated to investigate the failure mechanism of the foundation and the bearing characteristics of the riprap bed atop the soft soil. The results indicate that the shear modulus of the soil is related to the effective confining pressure and the shear strain; this relationship is fitted using the Van Genuchten equation. As the internal friction angle of the soft soil foundation decreases, its stability decreases nonlinearly, its strength decreases, and its sliding failure surface lengthens. However, simply increasing the riprap layer thickness has a limited effect on the overall wharf stability. These findings will improve the design of gravity wharves founded on soft soils in port areas with intense wave action. [ABSTRACT FROM AUTHOR]

Cavities are common subsurface anomalies that have a significant impact on the bearing capacity of footings. While cavities behave three-dimensionally, in previous studies, the analysis of cavities has been limited to two-dimensional plane-strain analysis because of the time-consuming nature and complexity of three-dimensional modeling. However, this study demonstrates that the bearing capacity factor derived from three-dimensional modeling can be up to 10 times higher than that obtained from plane-strain analysis, highlighting the importance of considering three-dimensional effects. The present paper conducted three-dimensional simulations to investigate the impact of spherical cavity on the failure mechanisms and bearing capacity of footings under undrained conditions. An extensive parametric study was performed to investigate the influential parameters, including footing width to cavity dimension ratio (B/D), cover depth ratio (C/D), overburden factor (γD/Su), and void eccentricity ratio (S/D) for both circular or square footings. The results indicate that increasing the overburden factor and void eccentricity ratio leads to a decrease and increase in the bearing capacity of the footing, respectively. Furthermore, changes in other parameters can either increase or decrease the bearing capacity depending on the characteristics of the cavity (size and location) and footing (size and shape). General solutions for the bearing capacity factor are provided for different variations of the dimensionless parameters. This study also examined various failure mechanisms, including both cavity-independent and cavity-dependent failure mechanisms, associated with circular and square footings and influential parameters. These mechanisms are categorized into three zones for cavity-independent failures and four zones for cavity-dependent failures. The changes in the influential parameters including B/D, S/D, γD/Su, and C/D lead to changes in the type of failure mechanism and the size of the failure zones, while the foundation shape does not have a significant effect on the failure mechanism. Sinkholes and underground cavities annually contribute to infrastructure damage and financial losses. The 1981 incident in Winter Park, Florida, exemplifies the real-world consequences. Previous investigations have been limited to two-dimensional models due to the time-consuming nature and complexity of three-dimensional modeling, but the real-world nature of cavities in three dimensions requires a more comprehensive understanding. This study directly addresses this need by investigating the impact of three-dimensional cavities on the bearing capacity of circular and square building foundations, also known as footings. This study thoroughly investigated the factors influencing the results, encompassing cavity size, depth, soil weight, and off-center position. It extensively explored potential footing failures, providing detailed discussions. Our findings are presented as easy-to-understand maps and charts covering a broad range of potential scenarios. These visual tools can help engineers and researchers accurately estimate the stability of a building's foundation when a cavity is present underneath. In simpler terms, this research has created a handy tool for professionals to predict the potential danger posed by hidden cavities to buildings and infrastructure. This knowledge can then be applied to ensure safer building practices, potentially saving a significant amount of money and preventing accidents in the future. [ABSTRACT FROM AUTHOR]

In any high-rise building construction based on piles, it is essential to correctly evaluate their response when subject to high loads to avoid oversizing and consequently high costs. This work falls within the framework of the FONDASILEX project, which studies the behaviour of the pile foundations and the soil within the 'Silex2' tower project built in the Part-Dieu district in Lyon, France. This paper presents the geotechnical instrumentation executed for the foundations and the soil to enable the real-time monitoring of their behaviour. It details its conception, execution and limits. Five different types of electrical and unconventional sensors, including the fibre optic technique, which is based on reflectometry by Rayleigh scattering, were employed. This instrumentation allowed us to measure the soil settlement, the applied load at the head of the pile and the induced deformation in the concrete. The obtained measurements showed good agreement between all the sensors and were compatible with the real applied load. The results of this monitoring completed with an additional specific study to characterize the soil will be used in a future study to calibrate numerical models simulating the behaviour of high-rise building foundations. [ABSTRACT FROM AUTHOR]

Researchers analyzed data from 14 participants in a collaborative, interarts, intergenerational community partnership project entitled "An Evening with Harvey Dunn's Feminine Images," to understand the effects of the project design on participant learning. The year-long project included collaboration among faculty and students from six disciplines at South Dakota State University (SDSU) in Brookings, South Dakota, using four paintings by artist Harvey Dunn as its inspiration. In addition, partnerships with the South Dakota Art Museum and a local dance studio provided community engagement with diverse age groups. The project created an environment in which an interarts and intergenerational cohort of learners explored diverse learning opportunities within a new context. Rich description from participant experience helped researchers understand how the project's structural framework was perceived by participants, what the participants learned, and how that learning aligned within Chad Hoggan's (2016) metatheory of transformative learning.

Tabriz, one of the metropolises of Iran, has a particular geotechnical condition. Recently, it has been reported that some of the new structures are tilted in Freshteh town located in the northwest of Tabriz. Different thicknesses of the first subsurface layer, the high level of ground water, and the presence of sand layers between the clay layers are the main reasons for uneven consolidation settlement of buildings in the mentioned area. Residents usually do not feel safe to live in these tilted buildings. However, demolishing and reconstructing tilted structures is a waste of money, unless there is no other solution. Moreover, the demolishing of valuable historical buildings is out of choice. Thus, restoration processes for tilted structures should be considered and developed. Various methods are used to rectify the tilted structures including compaction grouting, underpinning of the foundation, chemical grouting, jacking, soil extraction technique, etc. Among different methods for rectifying uneven settlement of structures, in this study, because of some advantages, the jacking technique has been chosen to rectify the Tilted Reinforced Concrete (RC) buildings. This method can be used in dense urban areas and the residents can stay in their apartment or office in much of the rectifying process. Geotechnical finite element software of Midas GTS NX was used for numerical modeling and analysis of this direct soil-structure interaction rectifying project. The results were verified based on the data reported by Ma et al. (2008). The force applied by the jacks to rectify the uneven settlement should continue until the two sides of the foundation would reach the equal value of vertical displacement, or the uneven settlement of the foundation is reduced to the minimum possible amount. Also, the structural elements of the building should be able to withstand the force applied by the jack and do not crack or collapse during the rectification stages.

Reservoir water-level fluctuation can alter the bearing capacity and stability of foundations on bank slopes by changing local seepage and stress fields, thus inducing displacement deformation of building foundations. A 2D saturated-unsaturated seepage model was constructed with ABAQUS for simulation calculation of the bank slope and buildings in the Shanganping Village, Wushan Section of the Three Gorges Reservoir Region, China. This task was conducted to investigate the influencing law of reservoir water-level fluctuation on building foundations on bank slopes and assure their safety. Subsequently, a comparative analysis about the variation laws of underground water and stresses and displacement of building foundations on bank slopes when the reservoir water-level fluctuation rate varies was carried out. Results show that the height ratio of the trailing saturate line at the side slope is 1.19 when the rate of the reservoir water-level rise is 1 and 3 m/d. Such finding indicates that the hysteresis effect of saturation line is highly obvious when the rate of the reservoir water-level rise is high. The maximum difference of effective stresses at the bottom of the pile foundation is 5 KN when a reservoir water-level fluctuation exists. This finding reveals that the reservoir water-level fluctuation will induce great changes to the stress state of building foundations. The maximum displacement of pile foundation is positively related with the rate of reservoir water-level fluctuation. Such a notion reflects that the rate of reservoir water-level fluctuation is a key influencing factor of deformation behaviors of bank slopes and buildings. During a reservoir water-level fluctuation, the settlement value is negatively correlated with the distance between the pile foundation and the frontal edge of the side slope. The error of settlement between the finite element simulation and the theoretical calculation results is lower than 10%, which verifies the accuracy of the numerical simulation in this study. The research conclusions can provide some references to the safety evaluation of existing buildings and design of new buildings on bank slopes. [ABSTRACT FROM AUTHOR]

The vibration energy of the track slab can be converted into electric energy for wireless sensors by piezoelectric energy harvesters. A track laminated circular plate harvester (TLCP harvester) is designed in this paper based on foundation excitation. The central frequency of the harvester is 222 Hz, which is matched with the 222.8 Hz of the track slab. The stiffness curve, damping, equivalent capacitance, and electromechanical coupling coefficient of the harvester are obtained through the experiment. The harmonic balance method and Runge–Kutta's voltage results are consistent with the experimental results. The frequency responses verify the jump phenomenon and soft characteristics. The experiment results show that the maximum output power is 8.07 mW under 7 kΩ load resistance, and the maximum RMS power is 0.3804 mW under 5 kΩ load resistance. This paper develops a safe and high-efficiency piezoelectric energy harvester for track slabs. [ABSTRACT FROM AUTHOR]

Sediment scour numerical simulation plays a critical role in the design of water-resistant foundation engineering, and this paper addresses a significant gap in most related studies, which often overlook the transformation of sediment and struggle to identify the actual riverbed obscured by yielding bed and suspended load. To tackle this challenge, a comprehensive sediment model based on the meshless Smoothed Particle Hydrodynamics (SPH) method was developed. Firstly, to enhance computational efficiency and mitigate the high cost of Fluid-Solid Interaction (FSI) between water and sediments, cohesionless sediment grains were modelled as non-Newtonian fluids, with yield strength determined according to a combined strength criterion. Subsequently, sediment transformation and identification were determined based on sediment particle velocity and shear stress, with the seepage force driving yield sediment particle motion at the interface. The effectiveness of this comprehensive sediment model was validated through comparison with three scour experiments. The results show better agreement between the model and experimental data, with a root-mean-square error of less than 2.17% in scour morphology simulation and successful identification of the actual post-scouring bed surface in each case. However, the free surface simulation in this model still exhibits slight error, with a root-mean-square error of less than 8.35%. [ABSTRACT FROM AUTHOR]