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This paper investigates the use of a protective pile row barrier to mitigate the risk due to a deep excavation in soft soils adjacent to an existing tunnel. The study includes two reduced-scale 1 g model tests with and without the barrier, along with monitoring data from a case history in Wuhan, the Huazhong Science and Technology Industrial Park basement; physical testing and numerical sensitivity study results are compared to the case history to evaluate the barrier efficiency. The monitoring data show successful excavation and basement construction within allowable displacement thresholds in the presence of the barrier. The entire tunnel settled and translated towards the excavation, although different types of ovalization of the tunnel cross-sections were recorded depending on their alignment to the excavation (centre and corners). Experimental results indicate that the pile row barrier can withstand a portion of the soil pressure on the diaphragm wall, leading to a substantial reduction in tunnel bending moments and displacements; in particular, experimental results showed a greater percentage reduction in settlements than horizontal movements of the existing tunnel. When a pile row barrier is constructed in proximity to the retaining wall, it can help to minimise the detrimental effects of the deep excavation on the existing tunnel, similar to twin retaining wall scenarios. [ABSTRACT FROM AUTHOR]

This paper presents two case studies dealing with undesirable impacts of overburden drilling of casings for end-bearing piles to bedrock. Monitored pore-water pressures and ground settlements are used to document and assess the influence from rotary percussive drilling with "down-the-hole" (DTH) hammers. The studies show that drilling with high-pressure air-driven DTH hammers may cause considerable erosion and soil volume loss adjacent to the drill bit and along the casing, resulting in settlements of the surrounding ground. The risk of soil volume loss increases when the drilling is carried out in erodible soils such as silt and fine sands. The volume loss is found to be caused by a combined air-lift pump effect and a Venturi suction effect. Monitoring pore pressures in the vicinity of the drilling may be used to reduce soil volume loss and prevent damaging settlements. Results from drilling with water-driven DTH hammer showed significantly less ground settlements and influence on pore pressures compared to using an air-driven hammer. The study suggests that the drilling parameters flow rate and penetration rate, and the cross-sectional area of the pile casing can be combined in a non-dimensional methodology to assess the mass balance of drill cuttings when drilling with water flushing. A design framework is suggested to guide overburden drilling in urban settings to reduce potential impact on the surroundings. [ABSTRACT FROM AUTHOR]

To consider the complex soil-structure interaction in a pile-slope system, it is necessary to analyze the performance of pile-slope systems based on a three-dimensional (3D) numerical model. Reliability analysis of a pile-slope system based on 3D numerical modeling is very challenging because it is computationally expensive and the performance function of the pile failure mode is only defined in the safe domain of soil stability. In this paper, an efficient hybrid response surface method is suggested to study the system reliability of pile-reinforced slopes, where the support vector machine and the Kriging model are used to approximate performance functions of soil failure and pile failure, respectively. The versatility of the suggested method is illustrated in detail with an example. For the example examined in this paper, it is found that the pile failure can significantly contribute to system failure, and the reinforcement ratio can effectively reduce the probability of pile failure. There exists a critical reinforcement ratio beyond which the system failure probability is not sensitive to the reinforcement ratio. The pile spacing affects both the probabilities of soil failure and pile failure of the pile-reinforced slope. There exists an optimal location and an optimal length for the stabilizing piles.

Cyclic loads generated by environmental factors, such as winds, waves, and trains, will likely lead to performance degradation in pile foundations, resulting in issues like permanent displacement accumulation and bearing capacity attenuation. This paper presents a semi-analytical solution for predicting the axial cyclic behavior of piles in sands. The solution relies on two enhanced nonlinear load-transfer models considering stress-strain hysteresis and cyclic degradation in the pile-soil interaction. Model parameters are calibrated through cyclic shear tests of the sand-steel interface and laboratory geotechnical testing of sands. A novel aspect involves the meticulous formulation of the shaft load-transfer function using an interface constitutive model, which inherently inherits the interface model's advantages, such as capturing hysteresis, hardening, degradation, and particle breakage. The semi-analytical solution is computed numerically using the matrix displacement method, and the calculated values are validated through model tests performed on non-displacement and displacement piles in sands. The results demonstrate that the predicted values show excellent agreement with the measured values for both the static and cyclic responses of piles in sands. The displacement pile response, including factors such as bearing capacity, mobilized shaft resistance, and convergence rate of permanent settlement, exhibit improvements compared to non-displacement piles attributed to the soil squeezing effect. This methodology presents an innovative analytical framework, allowing for integrating cyclic interface models into the theoretical investigation of pile responses.

This paper proposes a practical approach for data-efficient metamodeling and real-time modeling of laterally loaded monopiles using physics-informed multifidelity data fusion. The proposed approach fuses information from one-dimensional (1D) beam-column model analysis, three-dimensional (3D) finite element analysis, and field measurements (in order of increasing fidelity) for enhanced accuracy. It uses an interpretable scale factor–based data fusion architecture within a deep learning framework and incorporates physics-based constraints for robust predictions with limited data. The proposed approach is demonstrated for modeling monopile lateral load–displacement behavior using data from a real-world case study. Results show that the approach provides significantly more accurate predictions compared to a single-fidelity metamodel and a widely used multifidelity data fusion model. The model's interpretability and data efficiency make it suitable for practical applications. [ABSTRACT FROM AUTHOR]

In an effort to investigate and quantify the patterns of local scour, researchers embarked on an in-depth study using a systematic experimental approach. The research focused on the effects of local scour around a set of four piles, each subjected to different hydromechanical conditions. In particular, this study aimed to determine how different attack angles—the angles at which the water flow impinges on the piles, and gap ratios—the ratios of the spacing between the piles to their diameters, influence the extent and nature of scour. A comprehensive series of 35 carefully designed experiments were orchestrated, each designed to dissect the nuances in how the gap ratio and attack angle might contribute to changes in the local scour observed at the base of pile groups. During these experimental trials, a wealth of local scour data were collected to support the analysis. These data included precise topographic profiles of the sediment bed around the pile groups, as well as detailed scour time histories showing the evolution of scour at strategic feature points throughout the test procedure. The analysis of the experimental data provided interesting insights. The study revealed that the interplay between the gap ratio and the attack angle had a pronounced influence on the scouring dynamics of the pile groups. One of the key observations was that the initial phases of scour, particularly within the first hour of water flow exposure, were characterized by a sharp increase in the scour depth occurring immediately in front of the piles. After this initial rapid development, the scour depth transitioned to a more gradual change rate. In contrast, the scour topography around the piles continuously evolved. This suggests that sediment displacement and the associated sculpting of the seabed around pile foundations are sustained and progressive processes, altering the underwater landscape over time. The results of this empirical investigation have significant implications for the design and construction of offshore multi-pile foundations, providing a critical reference for engineers and designers to estimate the expected scour depth around such structures, which is an integral part of decisions regarding foundation design, selection of structural materials, and implementation of scour protection measures. [ABSTRACT FROM AUTHOR]

This research adopts emerging machine learning techniques to tackle the soil–structure interaction analysis problems of laterally loaded piles through physics-informed neural networks (PINNs), which employs prior physical information in the form of partial differential equations during the model training, eliminating the tremendous data requirement in the traditional data-driven machine learning methods. The formulations to describe the problem are discussed, and the corresponding governing equations are derived. A PINN framework, including neural networks architecture and loss functions, is developed for the machine learning-based solution and elaborated with details. The corresponding model training process is presented, based on which the surrogate model construction and back analysis implementation are introduced to demonstrate the effectiveness and flexibility of the proposed method. This method has been demonstrated for its accuracy via several examples with benchmark solutions from the existing well-developed methods. Finally, a case study of the uncertainty evaluation of a laterally loaded pile is conducted to illustrate its high computational efficiency and advantages in potential engineering applications. [ABSTRACT FROM AUTHOR]

The paper analyses the behavior of a rigid passive pile embedded in a soil profile consisting of a stable layer underlying an unstable layer subjected to a uniform soil displacement. Pile-soil interaction is considered by modeling the soil by a series of elastic–plastic springs along the pile shaft. The modulus of horizontal subgrade reaction is assumed to linearly increase with depth in the unstable layer and constant in the stable one. The ultimate soil resistance is assumed increasing with depth in both layers. The results of analysis are presented in dimensionless form in terms of shear force developed at the slip surface as a function of the pile embedment into the stable layer and the distribution of soil characteristics over depth. The method allows capturing pile response not only at the soil ultimate state but also at the intermediate states. Specifically, the governing equations for the elastic, elastic–plastic and plastic cases are discussed and, whenever possible, a set of closed-form expressions is provided to estimate the maximum bending moment along the shaft and the pile head deflection, so that for an assigned value of the required stabilizing force both ultimate and serviceability limit state of the pile can be checked. A numerical example is given to illustrate the application of the proposed procedure. [ABSTRACT FROM AUTHOR]

It is nowadays recognized that the load-transfer P-Y curves methods offer a powerful framework of analysis of the pile response under lateral loading. The aim of this paper is to present a new formulation the P-Y curves to analyze the response of a single pile embedded in clayey soil, on the basis of the CPT test data. The methodology of work consists of analyzing 8 lateral loading tests on fully instrumented piles driven into a homogeneous saturated clayey soil. The P-Y curves were formulated by the PARECT (parabola-rectangle) function, and successful correlation of their parameters, namely the lateral reaction modulus and the lateral soil resistance, with the cone resistance as well as with the lateral pile/soil stiffness ratio was made. After a comparison with the existing P-Y curves methods, a methodology of analysis by the proposed P-Y curves for piles in normally consolidated to slightly over-consolidated clays was suggested. Moreover, a pile classification according to the pile/soil stiffness ratio was suggested, and the concept of the critical deflection corresponding to the threshold of domain of large deflections of piles was introduced. Validation process was launched by applying this methodology to a centrifuged scale model of a single bored pipe pile in a saturated slightly over consolidated clay. Direct comparison of the load-deflection curves showed an excellent prediction of the small deflections up to about 2% of the pile diameter. Beyond this value, the boundary conditions at the pile tip have an influence on the results, but showed a relatively pessimistic prediction.

Several research studies have been conducted to strengthen weak road layers, regardless of whether they are under construction or constructed, and require maintenance using substrates filled with different materials, which have proven effective in increasing the strength of these layers. In this study, the objective of the work is to identify the maximum and minimum values of the coefficient of lateral soil pressure under various conditions when using reinforced and unreinforced piles filled with sand or granite grains and the extent of their contribution to strengthening road layers. An experiment was conducted using a box filled with soil, piles filled with sand grains or granite grains. It’s confirmed that there is a difference between the coefficients of lateral soil pressure when the piles are unreinforced or reinforced by dividing the sample into 2,3,4,5,6 parts by arming. The study found that the maximum value of the coefficient of lateral soil pressure in the case of sand (1 mm) reinforced is 0.38, whereas the maximum value in the same case with no reinforcement is 0.29. The maximum value of the coefficient of lateral soil pressure in the case of granite grain (2 mm) reinforced is 0.27, whereas the maximum value in the same case without reinforcement is 0.17. Moreover, the maximum value of the lateral pressure coefficient in the case of gravel (3 mm) reinforced is 0.26, and the maximum value in the same case without reinforcement is 0.30.

Earthquake-induced soil liquefaction can cause soil settlement around piles, resulting in drag load and pile settlement after shaking stops. Estimating the axial load distribution and pile settlement is important for designing and evaluating the performance of axially loaded piles in liquefiable soils. Commonly used neutral plane solution methods model the liquefiable layer as an equivalent consolidating clay layer without considering the sequencing and pattern of excess pore pressure dissipation and soil settlement. Moreover, changes in the pile shaft and the tip resistance due to excess pore pressures are ignored. A TzQzLiq numerical model was developed using the existing TzLiq material and the new QzLiq material for modeling liquefaction-induced downdrag on piles. The model accounts for the change in the pile's shaft and tip capacity as free-field excess pore pressures develop or dissipate in soil. The developed numerical model was validated against data from a series of large centrifuge model tests, and the procedure for obtaining the necessary information and data from those is described. Additionally, a sensitivity study on TzLiq and QzLiq material properties was performed to study their effect on the developed drag load and pile settlement. Analysis results show that the proposed numerical model can reasonably predict the time histories of axial load distribution and settlement of axially loaded piles in liquefiable soils both during and postshaking.

Copyright of Journal of Engineering (17264073) is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The advantages of the FCAW-S technology when making circumferential welded joints of pipes with a diameter of up to 2520 mm are indicated. The rational shape of edges prepared for welding pipes with a wall thicknesses of up to 40 mm is proposed. It is shown that it is possible to construct assembly and welding areas (jigs) for site assembly of products at extremely low temperatures using exclusively domestic main equipment. [ABSTRACT FROM AUTHOR]

This study addresses the problem of selecting an equivalent material for soil testing using piles on a large-scale experimental setup. The approach involved conducting model tests in a metallic tank with specific dimensions, allowing for a 1:25 scale. Fine and medium-grained sand was used as the equivalent soil material. The main criterion for sand selection was its similarity to medium-sized sand (0.25-0.50 mm). To ensure test reproducibility, only one sand fraction corresponding to the medium size was used. The results revealed that the chosen sand composition (Type 1) exhibited optimal homogeneity and particle size distribution. For modeling equivalent clay, Type 4 fine sand with 4% oil content was found to be the most suitable, demonstrating increased shear strength. The study concludes that the methods used effectively evaluate the load-bearing capacity of foundation piles, providing insights for optimizing designs for enhanced stability in diverse soil conditions. This approach paves the way for developing sustainable and ecologically efficient engineering structures in varying soil environments. [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]

This paper investigates the response of finned piles in sand subjected to static lateral load through laboratory tests and full-scale field tests. Firstly, model tests were carried out on free headed single piles of different shaft diameters with and without fins in sand to explore the performance of the piles under lateral loading. The results obtained from monotonic loading tests on three series of piles of three different combination of fins and pile shaft diameters were presented. The effect of fins on improving the stiffness and ultimate lateral capacity of the piles was discussed. An equivalent diameter was proposed for a finned pile, which enabled the experimental results to be back calculated using an available elasto-plastic solution for laterally loaded piles in sand. Secondly, field tests were conducted on laterally loaded Starfin screw piles in loose to medium dense sand. The proposed approach was then used for the analysis of the measured response of Starfin screw piles and further validated against measured test results from fully instrumented finned piles in overconsolidated dense sand. The results show that the proposed equivalent diameter and approach for the analysis of finned piles provided the most satisfactory match to the measured data, ranging from the initial elastic state to the ultimate limit state. [ABSTRACT FROM AUTHOR]

Physics‐informed neural networks (PINN) is an emerging machine learning technique and has been applied in different areas successfully. To benefit pile analysis from this innovative technique, this paper addresses several problems that arise when extending PINN to the large deflection analysis of slender piles accounting for nonlinear Soil‐Structure Interaction (SSI). The governing equations for the structural behavior of piles, considering geometric nonlinearity, are elaborated at first, based on which a PINN framework is constructed correspondingly with a model training process. A series of normalization factors are introduced to the loss function to enhance model training stability. Additionally, a regression‐based soil resistance estimation is developed to prevent non‐convergence and instability that may occur during the model training when encountering non‐differentiable SSI. Extensive examples are provided to validate the robustness and accuracy of the proposed analysis method for piles under complex geological conditions. Furthermore, several case studies are conducted, revealing the necessity of appropriate loss normalization and the effectiveness of regression‐based estimation for reflecting non‐differentiable functions in the PINN study. [ABSTRACT FROM AUTHOR]

This paper presents a novel analytical formulation to study the impact of shear deformations on beam-columns and piles by means of the Timoshenko-Engesser’s and Timoshenko-Haringx’s theories. The proposed solution enables the analysis of lateral deformation or buckling, while considering the effect of shear deformations. It offers the flexibility to i) incorporate different boundary conditions at the ends of the element (e.g., semi-rigid connections and lateral transverse springs) and ii) consider an inhomogeneous elastic foundation. When certain variables are disregarded, the proposed GDE can capture particular cases of GDEs found in the literature for beam-columns and piles. Examples are provided to demonstrate the simplicity and practicality of the proposed method, and its accuracy is validated against available analytical or numerical methods. The influence of the shear effects, as computed from Engesser’s and Haringx’s methods, on the lateral and buckling responses of beam-column and pile elements is discussed.

The effect of geocell-reinforced cushion on load distribution and settlement reduction in unconnected piled raft foundations was investigated. Modeling and analysis of various scenarios were carried out using Abaqus software. In this research, a total of nine models, including one connected, three unconnected and unreinforced, and five unconnected and reinforced with geocell, were analyzed. Cushions with thicknesses half of, equal to, and twice that of the foundation were used. The results have shown that optimal outcomes in terms of load distribution efficiency and settlement reduction are achieved when the cushion's stiffness is set at half that of the foundation. The obtained results demonstrate the positive effect of geocell reinforcement in enhancing the performance of unconnected piled raft foundations. The introduction of geocells into the models increases soil stiffness and pile load ratio, consequently enhancing the load-bearing capacity of the piled raft foundation compared to the unreinforced models. The study's findings pave the way for a more effective use of geocells in civil engineering applications, particularly in scenarios demanding high load-bearing capacity and minimal foundation settlement.

Earthquake-induced soil liquefaction can cause settlement around piles, which can translate to negative skin friction and the development of drag load and settlement of the piles. A series of centrifuge model tests were performed to assess liquefaction-induced downdrag and understand the interplay and effects of (1) pile embedment and pile-head load, (2) excess pore pressure generation and dissipation, and (3) reconsolidation and ground settlement on pile response during and postshaking. The model included a layered soil profile (clay, liquefiable sand, and dense sand) with two 635-mm-diameter instrumented piles. One pile was placed with its tip at the bottom of the liquefiable deposit; the other pile was embedded five diameters into the dense sand layer. The model was shaken with multiple earthquake motions with their peak horizontal accelerations ranging from 0.025 to 0.4 g. For each shaking event, the drag load on the piles first decreased during shaking and then increased during reconsolidation, exceeding its preshaking value. With multiple shaking events, the net drag load on the piles increased. The maximum observed drag load was found equal to the drained interface shear strength calculated from the interface friction angle of δ=30° and a lateral stress coefficient of K=1. Larger drag loads and smaller settlements were observed for the pile embedded deep in the dense sand layer. Most of the pile settlements occurred during shaking; postshaking pile settlement was less than 2% of the pile's diameter. The mechanisms behind the development of liquefaction-induced drag load on piles and settlements are described. Select ramifications concerning the design of piles in liquefiable soils are also described.

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Major structures like offshore platforms, wind turbines, transport infrastructure, tall buildings, etc., resting on soft compressible clays, are often supported by pile foundations. Apart from usual vertical loading (dead load, live load, etc.), these piles are subjected to significant cyclic loads arising from actions of waves, ship impacts, winds or moving vehicles. Under such circumstances, the lateral mode of cyclic loading is predominant and affects the overall foundation stability. Such repetitive loading leads to stress reversal in adjacent soft clay initiating progressive degradation in soil strength and stiffness, deteriorating the pile capacity with unacceptable displacements. Although several past studies investigated the response of single pile under lateral cyclic loading, a detailed investigation on pile group in clay subjected to cyclic lateral loading, which is of immense practical interest to field engineers, is yet to be carried out. In this paper, in-depth study has been carried out by developing a three-dimensional dynamic finite element model. Comparison of the computed results with available test data validates the numerical model. Extensive parametric studies with field data indicate that both the axial and lateral pile capacities and displacements have been significantly influenced by the cyclic loading parameters. Relevant design curves are also constructed. [ABSTRACT FROM AUTHOR]

Specific features of the manufacture and delivery of piles and welded pipe sheet piling (WPSP) for the construction of seaports in the Arctic zone are described. It is shown that it is necessary to update the GOST R 52664–2010 standard by expanding the range of standard sizes of manufactured WPSP to include a diameter of 2520 mm and to harmonize the requirements of GOST R 52664–2010 and GOST 33228–2015. [ABSTRACT FROM AUTHOR]

This work presents the results of work on import substitution of anticorrosive protective coatings of pile products of hydraulic structures for the categories of corrosion aggressiveness CX and immersion Im4. [ABSTRACT FROM AUTHOR]

Copyright of Firat University Journal of Experimental & Computational Engineering (FUJECE) is the property of Firat University Journal of Experimental & Computational Engineering (FUJECE) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the paper, there are examples of complex geotechnical problems in both 2D and 3D that are modelled using PLAXIS software on the specialist workstation provided by the Czech Geotechnical Society to their members. [ABSTRACT FROM AUTHOR]

The seismic design of pile foundations mainly relies on analyzing the seismic response of layered, liquefiable locations. Two design scenarios are taken into consideration from the case histories; the first is how pile foundations react to the stresses and lateral displacements brought on by the lateral dispersion of liquefied soil. The second is how to piles reaction to seismic activity that occurs with the development of high pore water pressures. The PLAXIS 3D software is utilized in this research with a non-linear soil constitutive model (hypoplastic model) for both dry and saturated loose sandy soils under the impact of two earthquakes and the motion of different features to give a complete understanding of the dynamic piled foundation response. The findings from this study show that the site profile, pile diameter, pile length, and excitation of ground motion significantly affect the dynamic response of the layered liquefied site. So, in the saturated case, the increase in the piles length to (L/D = 55) in comparison to the original length (L/D = 35) decreased the peak acceleration at the raft foundation by about (24.4 and 41.9) % under the effect of Kobe and Upland earthquake motion, respectively, while in the dry case, the reduction in peak acceleration was about (22.8 and 40.9) % under the effect of Kobe and Upland earthquake motion, respectively.

The most widely used analysis method for the laterally loaded pile problem is the Winkler spring approach. Although researchers have proposed nonlinear formulations for the p-y curves, the contribution of the soil nonlinearity has not been thoroughly studied. The main drawback of the current approach is the use of a single stiffness in the p-y formulation. This study investigates the laterally loaded pile problem by employing the pressure-dependent hardening soil model with small-strain stiffness (HS-Small Model), where the degree of soil nonlinearity is better integrated. The parametric analyses are performed on the verified model for various pile and soil properties. A new p-y model is proposed for pile behaviour under monotonic loading based on the numerical analysis results. The model includes the initial stiffness, ultimate soil resistance, and degree of nonlinearity parameters. The validity of the proposed model is demonstrated by simulating a centrifuge and two field tests from the literature. The proposed model accurately accounts for soil nonlinearity and significantly improves the estimation of lateral displacements.

The paper examines dynamic pile test data from 25 high-quality offshore cases, where end-of-initial driving (EoID) and beginning-of-restrike (BoR) instrumented dynamic monitoring was undertaken on tubular piles driven in sands at well-characterised sites after known setup periods. The static resistances derived from signal matching by two independent specialist teams using different software are compared with CPT-based pile capacity calculations, providing the first axial capacity and setup dataset for large offshore piles driven in sand. Complementary re-analyses are made from three onshore/nearshore sites where dynamic and static testing was conducted on comparable piles. Open-ended tubular steel piles with 0.3–3.5 m diameters driven in (mainly dense) sands are all shown to develop marked setup, which is most active over the first 2–10 days. All piles show similar outcomes 20–30 days after installation. However, the larger diameter offshore piles’ dynamic tests indicate no further setup after 30 days, while smaller diameter piles at onshore/nearshore sites continue to display further marked capacity growth. Comparisons of the axial shaft capacities inferred from signal matching with CPT-based design methods provides insights into the performance of the design methods. A trend for long-term pile shaft set-up to decrease with increasing diameter is identified and ascribed principally to the diameter-dependent constrained dilatancy that develops under axial loading at the pile-sand interface.

In the paper, there are examples of complex geotechnical problems in both 2D and 3D that are modelled using PLAXIS software on the specialist workstation provided by the Czech Geotechnical Society to their members.

Copyright of Journal of Engineering (17264073) is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With developments in maritime trade, the need to increase port capacities has emerged. It is important that the reconstruction of such port structures be carried out without disrupting the activities of the existing port and without damaging the old structures. However, the reconstruction and strengthening of these structures require significant engineering work. Especially in the design of such structures, geotechnical and structural engineering theories and practices need to be considered together. The most important challenge in this type of engineering design is to ensure harmony in geotechnical and structural analyses. In this study, the strengthening of a port structure in Guinea is taken as a case study. First, the existing quay wall was evaluated, and then the geotechnical and structural design of the new structure to be built for capacity increase was discussed. A geotechnical design was made with the Plaxis 2D program, and the structural design was made with the Sap2000 program. The soil behavior was analyzed nonlinearly with the Plaxis program and was modeled with the same accuracy as the Sap2000 program. In addition, pile capacities were confirmed by loading tests performed on the piles. The results show that complex hybrid solutions consisting of reinforced and unreinforced piles can be modeled with the finite element method. As seen from this case study, the capacities of existing port structures can be safely increased, provided that necessary geotechnical precautions are taken. [ABSTRACT FROM AUTHOR]

This paper presents an analytical study on the kinematic response of single cylindrical end-bearing piles embedded in homogeneous saturated soil, due to the propagation of seismic P-waves from the bedrock. The governing equations of soil are based on Biot's theory, while the pile is modelled as one-dimensional rod bonded to its surrounding soil. Solution of the pile and soil governing equations results in closed-form expressions for pile displacement and for the frictional force at the soil–pile interface. These expressions are employed to study the difference in the kinematic response of piles embedded in saturated two-phase soil, compared to piles in single-phase soil, and investigate the sensitivity of the axial kinematic response of piles to the main problem parameters. We show that ignoring the two-phase nature of saturated soil may result in significantly underestimating the amplitude of strong motion transferred to the base of pile-supported structures. [ABSTRACT FROM AUTHOR]

A closed‐form formulation for the dynamic analysis of lateral response of floating piles in a saturated finite‐thickness soil layer is presented in this paper. Governing equations of the saturated soil are established on the basis of Biot's poroelastic theory, solution to which results in the lateral resistance of surrounding saturated soil to pile deflection. Closed‐form expressions of the lateral deformations of pile along depth and the dynamic compliances at pile head are obtained by solving a system of linear equations from the boundary and continuity conditions, instead of solving sophisticated integral equations in existing boundary integral methods. The parametric study focuses on exploring the sensitivity of pile compliances and deformations to the main problem parameters, including pile‐soil modulus ratio and soil permeability. [ABSTRACT FROM AUTHOR]

A novel anchorage for long-span suspension bridges, called pile-caisson composite structures, was recently proposed by the authors in an attempt to reduce the construction period and costs. This study aims to investigate the displacement and force behavior of piles in a pile-caisson composite structure under eccentric inclined loading considering different stratum features. To this end, both 1g model tests and three-dimensional numerical simulations were performed. Two groups of 1g model tests were used to validate the finite-element (FE) method. Parametric studies were then performed to investigate the effects of groundwater level, burial depth of the pile-caisson composite structure, and distribution of soil layers on the performance of the pile-caisson composite structure. The numerical analyses indicated that the influence of the groundwater level on the stability of the caisson was much greater than that of the piles. In addition, increasing the burial depth of the pile-caisson composite structure can assist in reducing the displacements and improving the stability of the pile-caisson composite structure. In addition, the distribution of soil layers can significantly affect the stability of the pile-caisson composite structure, especially the soil layer around the caisson. [ABSTRACT FROM AUTHOR]

Thermally induced ratcheting of a thermo-active pile is the accumulation of net and irreversible pile head displacement upon heating–cooling cycles. Although this kind of phenomenon has been observed in vertically loaded piles in sand, it is unknown whether this exists in laterally loaded cases, and also what underlying mechanisms occur under the thermomechanical flexural soil–pile interaction. This study presents a series of centrifuge tests and finite-element simulations of the thermomechanical behaviour of a laterally loaded thermo-active pile in sand. A new model reinforced concrete (RC) was used in the centrifuge tests to mimic the thermal and mechanical properties of a prototype RC pile realistically. Ratcheting was evident in laterally loaded piles and its extent was more significant when the working horizontal load was higher. The ratcheting phenomenon was attributed to the accumulation of soil plastic strain due to the cyclic mechanical loading induced by pile thermal horizontal expansion and contraction, soil dilation upon soil–pile interface shearing and creep. The additional bending moment induced by the thermal action did not induce yielding within the pile. A subsequent numerical sensitivity study suggested that ignoring the softening behaviour of the sand would lead to underestimation of the magnitude of the accumulative thermally induced pile head lateral displacement. [ABSTRACT FROM AUTHOR]