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Helical piles are being increasingly considered for offshore applications as they avoid the acoustic emissions associated with pile driving, and they provide additional capacity relative to a driven pile. In this paper, the installation and tensile capacity of helical piles is considered through a combination of centrifuge experiments and large-deformation finite-element analyses within a coupled Eulerian–Lagrangian framework. The experiments provide a basis for validating the numerical simulations, but also quantify the expected installation torque and undrained tensile capacity, including the variation with time after installation. The numerical simulations extend the parameter space investigated experimentally, considering the number of helices, their spacing and pitch, in addition to the ratio of pile shaft to helix diameter and the profile of undrained shear strength. Mechanisms revealed through the numerical simulations are reflected in a new analytical model for calculating undrained tensile capacity, which is seen to agree reasonably well with the numerically and experimentally determined capacities. [ABSTRACT FROM AUTHOR]

An extensive database consisting of measurements of ground movements and pore pressures from 48 deep excavations is presented. The ground conditions for all cases are soft, normally consolidated clays, often underlain by a coarser layer of soil, i.e., confined aquifer, on top of bedrock. Traditionally wall and ground movements caused by deep excavations have been predicted without assessing effects of groundwater drainage or the influence of installation of tie-back anchors or foundation piles. This study clearly shows that the observed ground movements exceeded expected values based on induced shear movements and significant deformations occur at far distance from the excavation. The cause of the deformations is largely consolidation settlements due to pore pressure reduction, with a zone of influence recorded at up to 400 m distance from the excavation. The construction methods and opening of drainage paths to the confined aquifer is as important for pore pressure reduction, as exposing the confined aquifer itself. In addition, the groundwater drawdown is shown to be dependent on the ground conditions and mitigation measures. It is also shown that the pore pressure reduction and zone of influence may be very small if no drainage path is created, i.e., in case of strutted excavations and no piles or driven piles, or when the bedrock surface is not exposed. The drilling of tie-back anchors and piles are also seen to influence ground movements, especially at a distance of 2–4 times the excavation depth. Charts produced from the database enable estimation of expected groundwater drawdown including zone of influence. In addition, they can support decisions on construction methods, need for mitigating measures and extent of monitoring program in relation to deep excavations. [ABSTRACT FROM AUTHOR]

The increasing degree of urbanization has resulted in traffic and space congestion. When there is no longer any aboveground space for development, the existing space underground is excavated, and the construction of underground buildings is expected to solve the above problems. In the excavation of an underground layer, it is necessary to drive supplementary and existing piles into the soil to form a double-layer pile-supported structure. Aiming at an existing–supplementary double-layer pile-supported structure and considering the pile spacing of the supplementary piles, use of crown beams, and other factors, this study performed a series of indoor model tests and an simulation analysis in combination with finite element analysis software to reveal the bearing characteristics of this structure. The results showed that the installation of supplementary piles could effectively inhibit soil slippage after pile driving, redistribute the soil pressure load of the existing piles, and reduce the number of soil cracks between the piles. With the increase in the supplementary pile spacing, the deformation of the existing–supplementary double-stacked piles gradually intensified, and the bending moment of the pile body and the horizontal displacement at the top of the piles increased. The installation of crown beams in the existing piles could strengthen the connection between the existing and supplementary piles, reduce the number of soil cracks between these piles, and change the force mode of the pile body. Considering the geological conditions and the influence of existing buildings, the deformation laws of the supporting structure and the soil around the foundation piles during the excavation of an underground layer of an L-shaped foundation pit were revealed. The research results are expected to provide a scientific and theoretical basis for the design and construction of downward additional support structures for existing buildings, along with socio-economic significance. [ABSTRACT FROM AUTHOR]

In port dock engineering, high-piled wharves represent one of the primary structural forms. Damage to the foundation piles is a common issue, influenced by external loads such as impact forces during vessel berthing, slope deformations, and operational loads. This study focuses on the Jungong Road Wharf in Shanghai, utilizing FLAC 3D version 6.0 to conduct dynamic calculations under ship impact loading. The dynamic responses of the structure were analyzed, and various internal forces were extracted during the impact event. By combining concrete cracking failure criteria and fatigue damage theories, the effects of ship collisions on the cracking damage of high-piled wharf structures under different scenarios were assessed. Additionally, the applicability of modal flexibility in high-piled wharf scenarios was evaluated through finite element simulations. The results indicate that the dynamic amplification factor caused by dynamic loading is approximately 1.5, underscoring the necessity of considering this effect in the design and impact analysis of high-piled wharves. The impact loading significantly influences the bending moments of the piles, with inclined piles showing the greatest sensitivity. When a designed ship model collides with the high-piled wharf structure at a speed of 0.2 m/s, the tensile stress in the inclined piles reaches 87% of the ultimate tensile strength of the reinforcement. The impact loading has a relatively minor effect on the axial forces of the piles, a limited influence on the bending moments of the beams, but a considerable impact on the axial forces of the beams. Berthing by oversized vessels and unexpected incidents can lead to more severe damage to high-piled wharf structures. In the finite element simulations, modal flexibility effectively identified the locations of damage, with greater changes in modal flexibility correlating with increased damage severity. [ABSTRACT FROM AUTHOR]

Offshore windfarms are a key means to produce clean energy as we seek to limit climate change effects. Impulsive pile driving used for their construction in shallow water environments is among the most intense anthropogenic sound sources. There is an increasing understanding that an array of marine invertebrates detects acoustic cues, yet little is known about how pile driving sound could impact their sound detection abilities. We experimentally quantified potential changes in sound sensitivity for an abundant, commercially and ecologically important squid species (Doryteuthis pealeii) exposed to actual in situ pile driving. The pile was 0.3-m diameter and 10-m long; hammer energy reached 16 kJ per strike. Sound detection thresholds were determined using auditory evoked potentials in animals with no exposure, after one 15-min or five repeated 15-min long pile driving sound sequences, corresponding to cumulative sound exposure levels of 110 and 131 dB re (1 μm s−2)2 s for acceleration and 187 and 214 dB re (1 μPa)2 s for pressure. We found no statistical evidence of temporary threshold shifts in any squid exposed to pile driving sound sequences. These results, combined with companion behavioral studies, suggest that squid may be robust to the sound impacts during offshore windfarm construction. [ABSTRACT FROM AUTHOR]

The problem of calculating the ultimate bearing capacity of a screw pile is studied using the limit equilibrium theory in this paper. Calculation methods for the critical screw pitch and the ultimate bearing capacity under two representative failure modes are proposed. Four key parameters affecting the ultimate bearing capacity are compared and analysed, and design optimisation suggestions are put forward. The results illustrate that the ultimate bearing capacity of the screw pile is mainly affected by the shear strength of the soil, the height of the screw thread and the screw pitch. When designing the screw pile, the height of the screw thread could be increased and the screw pitch reduced to some extent. [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]

This paper aims to investigate the effect of combined end-and-side grouting on the bearing properties of large-diameter rock-socketed bored piles in highly weathered rock layers. Eight full-scale pile load tests were conducted in the highly weathered rock layer to analyze the enhanced mechanism of the combined grouted bored piles. The test data from pile mechanical testing were compared with the recommended values in the current specification and geological survey report. The results demonstrate significant improvement in the side and end resistances of the combined grouted bored piles, resulting in a substantial increase in the bearing capacity and effective settlement control. It was observed that the construction of impact holes for bored piles can cause severe damage to highly weathered rock structures and weaken the mobilization of side and end resistances. Moreover, it was found that the calculation of the enhancement coefficient in the current specification underestimates the practical bearing capacity. The measured enhancement coefficients for the side and end resistance of piles in fully or highly weathered rock layers range from 2.49 to 3.05 and 2.24 to 2.43, respectively, which are more reasonable and feasible for the calculation. The research findings deepen the understanding of the bearing characteristics of large-diameter rock-socketed bored piles with combined grouting and provide valuable case references for the optimal design of large-diameter combined grouted piles for building foundations in Shenzhen, China. Highlights: Post-grouting had the potential to improve super high-building foundation reliability while reducing pile length and cost. The improvement effect and improvement mechanism of combined grouted bored piles embedded in highly rock strata were revealed. The influence of the size effect for large-diameter piles in highly weathered rock was revealed. The construction of impact holes for bored piles can cause severe damage to highly weathered rock structures and weaken the mobilization of side and end resistances. The enhancement coefficients for the side and end resistance of piles in fully or highly weathered rock layers were proposed. [ABSTRACT FROM AUTHOR]

Corrosion is a major cause of deterioration in conventional steel-reinforced prestressed concrete (PC) piles installed in aggressive (marine) environments. As foundation members in bridges, deteriorated piles may result in failure or expensive repair or reconstruction. Corrosion resistant alternatives for reinforcing piles longitudinally and transversely include carbon fiber composite cables (CFCC) and stainless-steel (SS). However, the cost of these alternatives is prohibitive, which in turn increases the production cost of PC piles. To mitigate the high cost of CFCC and SS piles, the spirals in these corrosion resistant piles can be safely replaced by glass fiber–reinforced polymer (GFRP) bars in spiral form. In this research, the effectiveness of GFRP spirals in confining PC piles is presented by showing results of impact experiments conducted on full-size specimens. One control pile was reinforced with steel strands and spirals, while another pile was reinforced with steel strands and GFRP spirals. The spirals within the piles were instrumented at critical locations with strain gauges to record spiral responses. Externally, pile driving analyzer strain gauges and accelerometers were installed for pile response along loading direction. In addition, to further understand the spatial response of the piles tested, three-dimensional finite-element (FE) models were developed using a commercially available code to simulate the impact test. For the FE model, concrete behavior of was modeled using concrete damaged plasticity model, the behavior of steel strands was simulated using a bilinear elastoplastic material, and the GFRP spiral behavior was modeled using a linear elastic material. The results of the research show that PC piles can be confined with GFRP spirals, without decreasing the load-carrying capacity of the pile. Practical Applications: This research brought forth valuable insights with practical implications, particularly regarding the use of glass fiber–reinforced polymer (GFRP) spirals within prestressed concrete applications. The practical applications encompass several key points that stand to influence engineering practices. Notably, both experimental results and finite-element studies assert that prestressed concrete piles reinforced with GFRP spirals exhibit performance comparable to their traditional counterparts employing steel spirals. This similarity extends to a robust response under impact loads, indicating that prestressed concrete piles featuring GFRP spirals as lateral reinforcement can effectively withstand pile driving forces, rendering them suitable for practical applications. Furthermore, the study introduces the prospect of enhancing corrosion resistance in prestressed concrete piles by incorporating GFRP spirals in combination with corrosion-resistant strands. This development expands the feasibility of deploying corrosion resistant prestressed concrete piles for bridge foundations in marine environments. Engineers engaged in bridge construction projects are thus encouraged to explore the adoption of GFRP-reinforced prestressed concrete piles, anticipating enhanced durability and longevity for bridge structures, especially in regions subject to harsh environmental conditions. This plays a pivotal role in advancing resilient and sustainable infrastructure practices within the realm of civil engineering and construction. [ABSTRACT FROM AUTHOR]

Sound induced by impact pile driving is a possible risk to marine life. Therefore, it is common practice to use noise mitigation systems during piling to reduce the respective impact and to fulfill the prescribed noise limits. Scaling laws for the estimation of the underwater noise from unmitigated impact pile driving have been presented in von Pein, Lippert, Lippert, and von Estorff, "Scaling laws for unmitigated pile driving: Dependence of underwater noise on strike energy, pile diameter, ram weight, and water depth," Appl. Acoust. 198, 108986 (2022). This contribution shows how these scaling laws need to be changed if noise mitigation systems are considered. Scaling laws are developed for four different kinds of noise mitigation system setups. These include big bubble curtains, double big bubble curtain combinations, a fully absorbing system directly at the pile, and the combination of a system close to the pile and a double big bubble curtain. The derived scaling laws are verified and compared to publicly available measurement data. [ABSTRACT FROM AUTHOR]

The vibration force and amplitude are the two most important parameters in the analysis of the drivability ofcompacted sand pile vibration driving. The working amplitude is related to the mechanical equipment capacity and soilproperties, while the necessary amplitude is mainly related to soil properties. There are significant differences in theunderstanding of necessary amplitudes among the existing theories for analyzing the drivability of vibration driven piles. Inorder to better solve the problem of predicting the necessary amplitude for vibration pile driving, based on the analysis of thedrivability of compacted sand piles in the artificial island project of the Hongkong -Zhuhai -Macao Bridge and Tunnel, anacceleration sensor is installed on the sand pile pipe to monitor the entire process of compaction sand pile driving. Theamplitude time curve is obtained through quadratic integration. The measured amplitude under various soil conditions iscompared and analyzed with commonly used methods such as the Jiandiao Kobe Corporation Law of Japan, the ICE pile drivingtheory in the United States, and the PTC pile driving theory in France. Based on the measured results, the applicability andadvantages and disadvantages of the above vibration pile driving theory are compared and analyzed, and suggestions for thenecessary amplitude value method are given. The research results indicate that under the condition of using an electric vibrationhammer for pile driving, the necessary amplitude of the Jiandiao Kobe Corporation Law of Japan is larger, the necessaryamplitude of the French PTC method is smaller, and the regularity of the necessary amplitude of the American ICE method is ingood agreement with the measured results, but the value method is not specific enough. It is recommended to further refine andimprove the necessary amplitude values for vibration pile driving based on the ICE law in the United States and engineeringexperience. [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]

Screw piles (often referred to as helical piles) are widely used to resist axial and lateral loads as deep foundations. Multi-helix piles experience complex interactions between the plates which depend on the soil properties, pile stiffness, helix diameter, and the number of helix plates among other factors. Design methods for these piles are typically highly empirical and there remains significant uncertainty around calculating the compression capacity. In this study, a database of 1667 3D finite element analyses was developed to better understand the effect of different inputs on the compression capacity of screw piles in clean sands. Following development of the numerical database, various machine learning methods such as linear regression, neural networks, support vector machines, and Gaussian process regression (GPR) models were trained and tested on the database in order to develop a prediction tool for the pile compression capacity. GPR models, trained on the numerical data, provided excellent predictions of the screw pile compression capacity. The test dataset root mean square error (RMSE) of 29 kN from the GPR model was almost an order of magnitude better than the RMSE of 225 kN from a traditional theoretical approach, highlighting the potential of machine learning methods for predicting the compression capacity of screw piles in homogenous sands. [ABSTRACT FROM AUTHOR]

Micropiles are often implemented through drilling, steel pipe installation, reinforcement and grouting. However, in some parts of the world, especially in areas with fine-grained soils, these shafts are implemented by steel pile driving, followed by reinforcement, and grouting has been expanded considerably. In this study, micropile shafts were installed at the site by both driving and drilling methods. Reinforcement and grouting were carried out by two-step grouting and applying different grouting pressures in the micropiles. Some boreholes (at a distance of 0.3 m from the micropile axis) and test pits were drilled to investigate the penetration radius of the grout at different grouting pressures. Results showed that the bearing capacity of driven micropiles is about 4 to 14% more than that of drilled micropiles due to the soil compaction impacts. The average uniaxial compressive strength of the soil samples after micropiles grouting was dependent on the applied grouting pressure and increased from 25 to 56%. In addition, the direct shear test results showed an increase of 15% in the soil cohesion and an increase of 4° in the internal friction angle for the soil after grouting of the micropiles. [ABSTRACT FROM AUTHOR]

AbstractDifferent pile penetration methods will cause different pile penetration results. Therefore, it is very necessary to study the pile penetration mechanism under different pile penetration methods. In this paper, numerical simulations using the discrete element method (DEM) are carried out to investigate the meso-scopic mechanism of pipe pile penetration under jacking and driving methods. The mechanism is comprehensively compared and analyzed in terms of particle movement, changes in the force chain, displacement changes, resistance of penetration pile, soil lateral stress and soil vertical stress. Results show that the height of the soil plug in the jacked pile is lower than that in the driven pile. The degree of contact force chain at the bottom of the soil plug in the driven pile is slightly higher than that at the bottom of the soil plug in the pile of the jacked pile. The total resistance of the driven pile greater than that of the jacked pile. Within a certain distance below the pile tip, the jacked pile affects the vertical stresses of the soil in this area to a greater extent than the driven pile. Then, parametric sensitivity analysis is performed, which captures the effects of the penetration velocity in the jacking method and the hammering frequency in the driving method. This study can provide a reference for the selection of the penetration method of pipe piles in actual projects. [ABSTRACT FROM AUTHOR]

Underwater noise pollution from pile driving is now attracting increasing attention. However, most of the current numerical and semi-analytical models for predicting the noise are still expensive and time-consuming, and the near-field noise and far-field noise have to be obtained from different models. This paper proposes an efficient semi-analytical solution for predicting underwater noise in both near field and far field with only one model, whose computational efficiency is orders of magnitude higher than that of the finite element model. It is the first time that the Baranov–Novak thin-layer model for soil-pile interaction has been extended to the subject of underwater noise prediction during pile installation, taking into account pile-fluid-soil interaction. The solutions are obtained using the Laplace transform and the variable separation method. By comparing the prediction results with the five reported research cases, it is shown that the error of the proposed model is within reasonable limits for both near-field and far-field noise predictions. [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]

Excavation of foundation pits can cause deformation and differential settlement to nearby pipe gallery structures, potentially resulting in significant issues such as seepage and structural damage. Based on a deep foundation pit construction project for a residential building plot adjacent to the Wuhan-Jiujiang utility tunnel, a three-dimensional finite element analysis model with cement-soil mixed wall (SMW) and trench cutting remixing deep wall (TRD)-drilled pile is established to study the impact of the excavation process on the utility tunnel. The results indicate that as the foundation pit excavation depth increases, the lateral deformation of the drilled pile support structure shows an initial increase followed by a subsequent decrease, and the maximum lateral deformation occurs at the point approximately one-third from the bottom of the foundation pit. Besides, the surface settlement exhibits an initial increase, followed by a subsequent decrease and eventual stabilization. The deformation of the utility tunnel structure causing by excavation is always within specified limit of 15 mm. Compared to the structure before excavation, the maximum values of axial force, shear force, and bending moment of the utility tunnel increases by 0.09%, 0.14%, and 4.88%, respectively. The stress variation is small, which satisfies the safety requirements for its usage, the feasibility of the TRD-drilled pile support structure is demonstrated. This study can serve as a reference for safety assessment of comparable engineering projects. [ABSTRACT FROM AUTHOR]

In construction projects, conducting dynamic load tests on all piles proves impractical. Selective testing estimates bearing capacity, while the remaining piles rely on penetration depth for management. This approach, however, faces reliability issues due to varying conditions among piles. Technological advancements, such as non-contact hammers and sensors, have enhanced the accuracy of penetration depth measurements during final driving. Nonetheless, relying solely on penetration depth for construction and quality management remains problematic. This study, therefore, focuses on enhancing the use of driving formulas to improve pile quality management, particularly for the widely used pre-stressed high-strength concrete (PHC) piles. To improve pile quality management, existing driving formulas underwent review and refinement. Utilizing 258 dynamic load test data from various sites, the Hiley, Gates, and Danish formulas underwent validation through statistical analysis and graphical comparison. Enhancements to the Gates formula, achieved through curve fitting with actual data and the application of segment-based coefficients, demonstrated increased accuracy in bearing capacity estimation. These improvements offer a more reliable approach to pile quality management in construction projects. [ABSTRACT FROM AUTHOR]

The high-strain direct testing method is a novel technique for dynamic testing of pile bearing capacity, developed as an improvement to the traditional high-strain method. While its theoretical feasibility has been demonstrated through numerical simulations and laboratory experiments, its effectiveness in practical engineering applications remains uncertain. This paper discusses the foundational theory of the high-strain direct testing method, highlighting its clear calculation principles, straightforward process, and advantage of not requiring iterative fitting. The bridge project in Zhuhai, Guangdong Province, China, serves as a case study. An instrumentation layout for concrete-filled piles was designed based on the principles of the high-strain direct testing method, and data processing and analysis programs were developed using Python. Fifteen test piles were selected for field application of the high-strain direct testing method, with detailed analysis conducted on the results from four test piles. The test results were consistent with the soil layer distribution characteristics beneath the four piers of the bridge, validating the feasibility of this method in actual engineering practice. Subsequent static load tests on these four test piles allowed for a comparison with the high-strain direct testing method results, confirming the accuracy and reliability of the high-strain direct testing method for determining the bearing capacity of single piles. Furthermore, this paper identifies sources of error in the application of this method and proposes corresponding improvement measures. As this method directly derives results from instrumented measurements, it is theoretically applicable to piles of any cross-sectional shape and material, provided that enough measurement lines can be successfully arranged along the pile shaft. This capability allows for the real-time estimation of the ultimate bearing capacity during pile driving, thereby enhancing the universality of the high-strain direct dynamic testing method beyond traditional techniques. [ABSTRACT FROM AUTHOR]

Research on the types of deep foundation pit support for large water conservancy engineering tunnels, in order to provide new methods for deep foundation pit support and further expand the application scope of deep foundation pit support. By comparing the technical feasibility, sustainable development, and economic rationality of several types of support for deep foundation pits, such as cement soil piles, underground continuous walls, and interlocking piles, and combining with the stability calculation of deep foundation pit support, the safety of the support types is reviewed. The interlocking pile has good waterproof performance, high overall stiffness, and small deformation in deep foundation pits, ensuring the safety of excavation of the entrance slope of large water conservancy tunnels with poor geological conditions, and creating safe conditions for the smooth excavation and operation of tunnels; Adopting bite pile support at the entrance of the large cross-section tunnel takes up less space, effectively solving the difficulties of land acquisition and demolition. Dry hole operation makes it easy to form holes, and the construction speed is faster, creating conditions for timely completion of construction; The construction cost of bite pile is low, there is no need to discharge mud, and the mechanical equipment has less vibration and low noise. Compared with deep foundation pit support types, interlocking piles have higher economic, safety, and environmental friendliness, effectively enhancing the application range of interlocking piles and providing new methods for design. [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]

The reinforcement of soil with concrete columns, as well as pile foundations, is commonly used in building construction, particularly in cases where weak soils are present. This paper presents a comparative analysis of the foundation of an engineering structure using two methods: pile foundations and soil reinforcement with concrete columns. While both methods are similar in terms of execution, they differ in their working characteristics and calculation approaches. The structure analysed was a multi-family building consisting of two residential sections connected by an underground garage. Numerical analyses were conducted using the Finite Element Method (FEM). The load-bearing capacity of a single pile was calculated directly from the results of CPTU soundings using the LCPC method. The analysis led to the design of 1,096 concrete columns with a diameter of 300 mm and a total length of 7,485.5 metres, as well as 334 foundation piles with a diameter of 500 mm and a total length of 3,305.5 metres. The difference in concrete volume is approximately 120 m² in favour of the columns, which constitutes nearly 20% of the total concrete volume. The columns were primarily designed in concrete, which results in additional steel savings, as all foundation piles would require reinforcement. [ABSTRACT FROM AUTHOR]

Toppling accidents of heavy machinery such as pile drivers, cranes, high-altitude work vehicles, and jacks have been recurring in the world. In the past, researches focused to find the overturning moment that causes toppling. However, it is believed that the toppling accidents are related to structural stability issues, in which cases the accidents could possibly occur without any overturning moment. Accidents involving the structural instability are difficult to predict as the directions of load and deformation are different. This unpredictability is considered as a fundamental contributing factor to accidents recurring. Theoretical studies by static and dynamic analyses have been performed by the authors. It was found that not only static deformations but also dynamic inertial forces influence the increased risk of toppling. In the cases of structural instability, dynamic inertial force might amplify angular displacement beyond the critical stability angle, leading to rapid toppling and often resulting in significant disasters. Factors leading to toppling as a trigger include unexpected movement onto weak ground, increased magnitude of load and height, and greater ground incline. Taking those factors into consideration, this paper attempts to elucidate the mechanism of pile drivers' toppling by comparing static and dynamic analyses and providing essential information for preventing accidents. From both static and dynamic analyses, toppling behavior will be described in the load--deformation and the support stiffness--deformation relations. Furthermore, a role of temporal element is illustrated as a quick movement of the machines results in increased risk of toppling. [ABSTRACT FROM AUTHOR]

In this paper, joint precast piles with a cross-section of 400 × 400 mm and a pin-joined connection were considered, and their interaction with the soil of Western Kazakhstan has been analyzed. The following methods were used: assessment of the bearing capacity using the static compression load test (SCLT by ASTM) method, interpretation of the field test data, and the dynamic loading test (DLT) method for driving precast concrete joint piles, including Pile Driving Analyzer (PDA by ASTM) and Control and Provisioning of Wireless Access Points (CAPWAP) methods. According to the results, the composite piles tested by the PDA (by ASTM) method differ by 15 percent compared to the static load method, while the difference between the dynamic DLT (by ASTM) method and the static load (by ASTM) method was only 7 percent. So, according to the results, the alternative dynamic method DLT (by ASTM) is very effective and more accurate compared to other existing methods. [ABSTRACT FROM AUTHOR]

Pile running during the installation of offshore large diameter pipe piles poses a significant challenge to construction safety and pile bearing capacity. This paper proposes a deep learning (DL)-based method for predicting pile running occurrences. Utilizing a dataset of pile installation records collected from various construction sites, the DL model was trained and tested. The predictive capacity of the DL model was compared with conventional analytical methods, demonstrating its superior performance in terms of accuracy and robustness. Additionally, the SHAP (SHapley Additive exPlanations) method was employed for the sensitivity analysis of the model's input variables, and the resultant importance ranking agreed well with the findings of existing studies, thus enhancing the reliability and interpretability of the model's predictions. [ABSTRACT FROM AUTHOR]

Ultra-soft soil is distributed in coastal areas around the world and has poor engineering properties. There is a significant difference in settlement between semi-rigid pile and surrounding soil under embankment load. Based on existing research results, the settlement calculation formula of ultra-soft soil composite foundation reinforced by semi-rigid pile is derived in this paper. Based on the Alamgir displacement model, assuming a three-zone model of pile skin friction with a negative skin friction plastic zone in the upper part of the pile, an elastic zone in the middle part of the pile, and a skin friction-bearing plastic zone in the lower part of the pile, the upward and downward penetrations of pile, and pile–soil slip deformation characteristics are considered. Analytical expressions for settlement calculations of semi-rigid pile composite foundations under embankments were derived based on differential equations for pile–soil load transfer in the unit cell. The influences of pile diameter and the compression modulus of the underlying layer at the pile end on the settlement characteristics of the semi-rigid pile composite foundation are discussed. The results show that the derived theoretical calculation method is in good agreement with the field measurement and laboratory model test results. Ultra-soft soil composite foundations have long settlement stabilization times and large settlement deformations. Penetration deformation occurs at the semi-rigid pile end. The relationship between pile end resistance and pile end piercing deformation is hyperbolic. The compression modulus of the underlying layer has a great influence on pile end penetration. The lower the compression modulus of the underlying layer, the larger the penetration deformation of pile end. The larger the pile diameter is, the smaller the penetration deformation is. [ABSTRACT FROM AUTHOR]

When constructing hollow prestressed high-strength concrete (PHC) pipe piles in soft soil foundations, the generation and dissipation of pore water pressure can induce negative friction on the pile. This phenomenon increases the settlement of the pile foundation and, in severe cases, can lead to pile deflection and flotation. To further investigate the development characteristics of pore water pressure during PHC hollow pipe pile driving in soft soil, this study combined existing theories and numerical models to analyze the generation and influence areas of pore water pressure. Field tests were conducted at three different sites: an untreated site, a surcharge preloading site, and a site treated with cement mixing piles and well dewatering. These tests monitored and analyzed the horizontal and vertical development and behavior of pore water pressure during pile driving at each site. The results indicate that during the pile driving process, when the horizontal distance from the pile center is 3d and 9d, the peak values of the excess pore water pressure in the site treated with cement mixing piles and well dewatering are 117 kPa and 100 kPa. After pile driving is completed, they decrease to 50 kPa and 48 kPa, respectively. The peak values of excess pore water pressure in the surcharge preloading site are 122 kPa and 97 kPa, and after pile driving, they decreased to 80 kPa and 21 kPa, respectively. The peak values of excess pore water pressure in untreated sites are 140 kPa and 121 kPa; after pile driving, they decreased to 82 kPa and 60 kPa, respectively. Pore water pressure increases with the depth of pile driving and decreases with distance from the pile driving location. The peak pore water pressure and dissipation rate during construction were found to be higher at the untreated site compared to the other two sites. Therefore, during pile sinking in soft soil foundations, dewatering and driving drainage boards are effective methods for reducing pore water pressure and accelerating its dissipation. These findings provide a theoretical basis and technical support for ensuring the safety of engineering constructions. [ABSTRACT FROM AUTHOR]

This study proposes a constitutive model to simulate the clayey soil response to the external loads during soil-structure interaction, specifically in the context of pile installation and subsequent set-up. The model considers the alteration of soil structure during prolonged penetration and the gradual regaining of its thixotropic strength. The model is based on the disturbed state concept and critical state theory, with the Modified Cam-Clay model used to define the intact state response. The proposed model, referred to as the Critical State and Disturbed State Concept model, captures the elastoplastic behavior of both normally consolidated and over-consolidated soils. It was validated using triaxial test results and implemented in Abaqus software to simulate pile driving and the set-up phenomenon occurs after the end of pile driving. The model accurately predicts pile capacity and disturbance behavior in the soil, as demonstrated by field compression load tests. [ABSTRACT FROM AUTHOR]

The coupled Eulerian–Lagrangian (CEL) method implemented in Abaqus is an established tool for modelling large deformations in numerical geomechanics. As shown in previous work, it can be extended to a hydro‐mechanically coupled scheme by exploiting the similarity of the heat balance equation to the mass balance equation of fluids. However, the distinction between effective and total contact stresses has not been possible in this approach, which hinders its application to problems with interface friction as frictional stresses are calculated based on total normal contact stress. An approach to circumvent this problem is presented in this work. Its relevance is demonstrated by the simulation of vibratory pile driving model tests in water‐saturated sand. The implementation by means of user‐subroutines is available and works for any total‐stress analysis. [ABSTRACT FROM AUTHOR]

A series of small-scale 1 g model tests were conducted using a self-designed pile driving loading model test system to investigate the effect of relative density and cross-section geometry on the development of soil stress around the pile during the penetration of X-section Cast-in-place Concrete (XCC) pile in sand. It is found that the variations of the radial stress Δσ'r/σ'v0 in the surrounding soil presented a significant "h/R effect" during the penetration of the XCC pile, indicating that the "h/R effect", which was found for circular pile during the penetration of piles, was also observed for the XCC pile. The radial stress distribution along the axial direction of the pile could be divided into three zones, i.e., the pile body region, the pile tip region, and the soil region below the pile tip. The development trend of the radial stress along with soil depth is different in each region. Additionally, the peaks of the radial stresses in the pile tip region were very sensitive to the variations of the relative density of the surrounding soils and the cross-section geometry of the piles, which increased significantly with increasing the relative density and cross-section geometry. The radial stresses Δσ'r/σ'v0 decreased exponentially as the radial distance r/R increased. The decay rates decreased with increasing the relative densities of the surrounding soils, while increased with decreasing the cross-section geometry parameter of the piles. [ABSTRACT FROM AUTHOR]

This study presents a detailed investigation into the soil arching effects within deep foundation pits (DFPs), focusing on their mechanical behavior and implications for structural design. Through rigorous 3D finite element modeling and parameter sensitivity analyses, the research explores the formation, geometric characteristics, and spatial distribution of soil arching phenomena. The investigation encompasses the influence of key parameters such as elastic modulus, cohesion, and internal friction angle on the soil arching effect. The findings reveal that soil arching within DFPs exhibits distinct spatial characteristics, with the prominent arch axis shifting as excavation depth progresses. Optimal soil arching is observed when the pile spacing approximates three times the pile diameter, enhancing soil retention and minimizing deformation risks. Sensitivity analyses highlight the significant impact of soil parameters on soil arching behavior, underscoring the critical role of cohesive forces and internal friction angles in shaping arching characteristics. By elucidating the interplay between soil parameters and soil arching effects, the research provides insights for optimizing pile spacing and structural stability. [ABSTRACT FROM AUTHOR]

One of the common excavation methods in the construction of urban infrastructures as well as water and wastewater facilities is the excavation through soldier pile walls. The maximum lateral displacement of pile wall is one of the important variables in controlling the stability of the excavation and its adjacent structures. Nowadays, the application of machine learning methods is widely used in engineering sciences due to its low cost and high speed of calculation. This paper utilized three intelligent machine learning algorithms based on the excavation method through soldier pile walls, namely eXtreme gradient boosting (XGBoost), least square support vector regressor (LS-SVR), and random forest (RF), to predict maximum lateral displacement of pile walls. The results showed that the implemented XGBoost model performed excellently and could make predictions for maximum lateral displacement of pile walls with the mean absolute error of 0.1669, the highest coefficient of determination 0.9991, and the lowest root mean square error 0.3544. Although the LS-SVR, and RF models were less accurate than the XGBoost model, they provided good prediction results of maximum lateral displacement of pile walls for numerical outcomes. Furthermore, a sensitivity analysis was performed to determine the most effective parameters in the XGBoost model. This analysis showed that soil elastic modulus and excavation height had a strong influence on of maximum lateral displacement of pile wall prediction. [ABSTRACT FROM AUTHOR]

The shape of a blasted rock mass, or simply muckpile, affects the efficiency of loading machines. A muckpile is defined with two main parameters known as throw and drop, while several blasting parameters will influence the muckpile shape. This paper studies the prediction of the muckpile shape in open-pit mines by applying an artificial neural network designed by a genetic algorithm. In that regard, a genetic algorithm has been used in preparing the neural network architecture and parameters. Moreover, input variables have been reduced using the principal component analysis. Finally, the best models for predicting throw and drop determined. Analyzing the performance of the proposed models indicates their superiority in predicting the muckpile shape. As a result, the Mean Squared Error of the throw was 0.53 for the training data and 1.24 for the testing data. While for the drop, the errors were 0.45 and 0.58 for the training and testing data, respectively. Furthermore, the sensitivity analysis shows that specific-charge effects drop and throw more. [ABSTRACT FROM AUTHOR]

Current research deals with the numerical investigation of the behavior of helical piles resting in cohesionless soil subjected to compressive load. The effect of the diameter of pile shaft (DS), the diameter of the helical plate (Dh), the depth of the pile (H), the inter-helical spacing ratio (S/Dh) the number of helix (m), and the type of sand on the load-displacement behaviour of helical pile was evaluated. The numerically determined compression capacity of the helical pile was compared with the existing theories. Apart from this, the artificial neural network technique was employed on the obtained results to develop the model equation. An increase in the compression capacity of single and double helical pile was observed with an increase in the pile depth, the friction angle of sand, and the diameter of pile shaft. For double helical pile, the optimum inter-helix spacing ratio was found to be 3. [ABSTRACT FROM AUTHOR]

Understanding the role that settlement can have on the base resistance of piles is a crucial matter in the design and safety control of deep foundations under various buildings and infrastructure, especially for long to super-long piles (60–90 m length) in soft soil. This paper presents a novel assessment of this issue by applying explainable machine learning (ML) techniques to a robust database (1131 datapoints) of fully instrumented pile tests across 37 real-life projects in the Mekong Delta. The analysis of data based on conventional methods shows distinct responses of long piles to rising settlement, as compared to short piles. The base resistance can rapidly develop at a small settlement threshold (0.015–0.03% of pile's length) and contribute up to 50–55% of the total bearing capacity in short piles, but it slowly rises over a wide range of settlement to only 20–25% in long piles due to considerable loss of settlement impact over the depth. Furthermore, by leveraging the advantages of ML methods, the results significantly enhance our understanding of the settlement–base resistance relationship through explainable computations. The ML-based prediction method is compared with popular practice codes for pile foundations, further attesting to the high accuracy and reliability of the newly established model. [ABSTRACT FROM AUTHOR]

The Wave Equation Analysis of Pile Driving (WEAP) has been widely used to determine drivability, predict static resistance, and assure the integrity of piles in soils. Assigning static and dynamic properties of Soil-based Intermediate Geomaterials (S-IGMs) remains a challenge in WEAP, partly attributed to IGMs that act as transition geomaterials between soil and hard rock. Furthermore, reliable static analysis methods for unit resistance predictions are rarely available for driven piles in S-IGMs in the default WEAP method. To alleviate these challenges, this study presents improved WEAP methods for steel piles driven in S-IGMs, including proposed damping parameters and Load and Resistance Factor Design (LRFD) recommendations based on newly developed static analysis methods and the classification of S-IGMs. A back calculation approach is used to generate the appropriate damping parameters for S-IGMs for three distinct subsurface conditions utilizing a database of 34 steel H- and pipe piles. Newly developed WEAP and LRFD procedures are also recommended. Additional independent 22 test pile data are used to compare and evaluate the accuracy and efficiency of the proposed WEAP methods with the default WEAP method. Compared with the default WEAP, bearing graph analysis results revealed that the selected proposed WEAP method, on average, reduces the underprediction of pile resistances by 6% and improves the reliability with a 43% reduction in the coefficient of variation (COV). Calibrated resistance factors for the proposed WEAP method increase to as high as 0.75 compared to the current AASHTO recommendation of 0.50. An economic impact assessment reveals that the proposed WEAP method is more efficient than the default WEAP method as the average difference in steel weight for 32 test piles is 0.06 kg/kN, almost close to zero, reducing the construction challenges in the current engineering practice. [ABSTRACT FROM AUTHOR]

The Ningbo International Conference Center Project incorporates elements of Chinese traditional culture into its architectural style, resulting in the world's first cantilever bridge international conference center. During the construction process, it faced challenges such as complex engineering geological environments and diverse architectural styles. By harnessing building information modeling (BIM) technology, many challenges encompassing intricate environmental conditions, architectural structures, and construction complexities are effectively visualized in three dimensions, thereby offering viable solutions for engineering implementation. In the scheme design stage, BIM technology plays a pivotal role in bridging the gap between design and construction, optimizing engineering pile and wall material designs. During the deepening design stage, BIM aids in refining designs through intricate node optimization for the ultralong comb type inclined water panel curtain wall and glued wood column decoration, thereby enhancing construction efficiency. Additionally, BIM technology has also played an important role in the simulation and scheme analysis of the entire construction process of complex steel structures. Through the implementation of BIM technology, numerous challenges encountered during the construction phase of the Ningbo International Conference Center project have been effectively resolved, which serves as a valuable reference for employing BIM technology in large-scale international conference center projects. [ABSTRACT FROM AUTHOR]

The document discusses the advancements, challenges, and future prospects of insulation systems in High Voltage Direct Current (HVDC) transmission projects. It highlights the differences between DC and AC transmission, the increasing importance of HVDC projects in modern power grids, and the safety considerations associated with HVDC insulation systems. The document also presents research findings on various aspects of insulation systems, such as thermal aging characteristics of XLPE cables, sag calculation methods, energy storage density of dielectric materials, and fault identification techniques. Additionally, it addresses the development characteristics of partial discharge in oil-pressboard insulation and proposes a joint displacement control technique for tower foundations. The document concludes with a review of research on the external insulation characteristics of post insulators. [Extracted from the article]

The effects of high-intensity impulsive noise generated by pile driving on fish are a major concern in environmental impact assessments. Numerical acoustic models are essential for predicting underwater-acoustic-related problems in complex coastal environments prior to offshore construction. However, underwater noise modeling for impact pile driving has often been performed using simplistic propagation models that are inadequate for three-dimensional (3D) environments. A 3D parabolic equation method (PE) was established in this study to better predict broadband transmission loss (TL) from impact pile driving in complex coastal environments and its influence on the large yellow croaker (Pseudosciaena crocea). The effects of 3D propagation were investigated using two realistic scenarios with different bathymetric complexities. The values and attenuation rate of the broadband TL for the steeply sloped bottom were significantly greater than those for the flat and weakly varying bottoms over 3 km. At a water depth of 5 m, a difference of approximately 10 dB was observed between the two TL scenarios at a distance of 4.5 to 5 km. The simulation results are in reasonable agreement with the field measurement data, with a difference of less than 3 dB. The zones of behavioral response and injury in the large yellow croakerwere estimated using the For3Dmodel. The results showed that the effects of the noise generated by the impact pile driving on the large yellow croaker were evident and three-dimensional. Therefore, 3D propagation effects should be considered when analyzing the influence of underwater noise on marine animals. [ABSTRACT FROM AUTHOR]

Low-to-medium-density chalk can be destructured to soft putty by high-pressure compression, dynamic impact or large-strain repetitive shearing. These process all occur during pile driving and affect subsequent static and cyclic load-carrying capacities. This paper reports undrained triaxial experiments on destructured chalk, which show distinctly time-dependent behaviour as well as highly non-linear stiffness, well-defined phase transformation and stable ultimate critical states under monotonic loading. The chalk's response to high-level undrained cyclic loading invokes both contractive and dilative phases that lead to pore pressure build-up, leftward effective stress path drift, permanent strain accumulation, cyclic stiffness losses and increasing damping ratios that resemble those of silts. These outcomes are relatively insensitive to consolidation pressures and are distinctly different to those of the parent intact chalk. The maximum number of cycles that can be sustained under given combinations of mean and cyclic stresses are expressed in an interactive stress diagram which also identifies conditions under which cycling has no deleterious effect. Empirical correlations are proposed to predict the number of cycles to failure and mean effective stress drift trends under the most critical cyclic conditions. Specimens that survive long-term cycling present higher post-cyclic stiffnesses and shear strengths than equivalent 'virgin' specimens. [ABSTRACT FROM AUTHOR]

The pore-water pressure response during vibratory pile driving considerably affects the piling process and environment. With the applications of high-frequency technology in upgrading the vibratory hammer, the pore-water pressure variation under high-frequency driving conditions becomes more complicated. However, there is a lack of relevant detailed investigations. This paper conducts an in situ experiment with a comprehensive monitoring and measuring system to examine the pore-water pressure response in the complete process of high-frequency vibratory pile driving. The real-time variations of pore-water pressure at the pile-soil interface and surrounding soil are evaluated, respectively. Furthermore, the excess pore-water pressure distributions and evolutions are analyzed in-depth. Then, the mechanism analysis and affected zone range determination are performed based on the development of excess pore-water pressure. The analysis results indicate that vibratory pile driving with high frequency leads to an increase of excess pore-water pressure and consequently soil quasi-liquefaction at the pile-soil interface. The apparent accumulation of excess pore-water pressure concentrates in the local range of soil around the pile tip and decays rapidly in the radial direction. According to the field observations, the increase of the pore-water pressure in the surrounding soil is attributed to the frictional penetration of the pile tip and the frictional vibration of the pile shaft. Furthermore, the maximum radial radii of the fully and partially quasi-liquefied zones are approximately 2.9 and 3.6 times the pile diameter, respectively. [ABSTRACT FROM AUTHOR]

Soil setup has a significant contribution to the performance of jacked piles in natural clays with structure characteristics. In this paper, a series of model pile tests are conducted to investigate the pile setup in structured clays, focusing on the influence of soil structure on time-dependent pile response. Three artificially structured clays are prepared as model soils to avoid the sampling challenge of undisturbed clays. The model tests are capable of modeling pile response through installation, equalization, and loading, and hence the initial structure and stress-induced structure degradation of clays, as well as the following thixotropic effect and reconsolidation of disturbed clays, can be adequately incorporated. Meanwhile, the behaviors of the piles and pile–soil interface are constantly monitored by the measurement system during and after pile installation. The results demonstrate that by increasing the cement content of structured clays from 0 to 4%, the penetration resistance is almost doubled, and the pore water pressure (PWP) and radial stress of the pile–soil interface located 20 cm from the pile toe increase by 1.27 and 1.38 times, respectively. A higher cement content in model soils leads to a quicker dissipation of excess pore water pressure (EPWP) due to the presence of a larger void structure and a smaller zone of damage caused by pile driving in structured clays. The growth rate of the ultimate bearing capacity of piles increases sharply with the cement content. The normal stress of the interface first decreases slightly and then grows dramatically with the mobilized shear stress during static loading tests. [ABSTRACT FROM AUTHOR]

The dynamic (acoustic pressure) and kinematic (acoustic acceleration and velocity) properties of time-limited signals are studied in terms of acoustic dose metrics as might be used to assess the impact of underwater noise on marine life. The work is relevant for the study of anthropogenic transient acoustic signals, such as airguns, pile driving, and underwater explosive sources, as well as more generic transient signals from sonar systems. Dose metrics are first derived from numerical simulations of sound propagation from a seismic airgun source as specified in a Joint Industry Programme benchmark problem. Similar analyses are carried out based on at-sea acoustic measurements on the continental shelf, made with a vector sensor positioned 1.45 m off the seabed. These measurements are on transient time-limited signals from multiple underwater explosive sources at differing ranges, and from a towed, sonar source. The study demonstrates, both numerically and experimentally, that under many realistic scenarios, kinematic based acoustic dosage metrics within the water column can be evaluated using acoustic pressure measurements. [ABSTRACT FROM AUTHOR]

Many instances of severe damage to pile foundations and pile-supported infrastructures have been caused by liquefaction-induced lateral spreading during major earthquakes, particularly in coastal areas. The current study conducted a series of shaking table experiments to determine the differences between the responses of a free- and a fixed-head group pile under lateral spreading in the presence of finned and circular protection piles. The results indicated that the maximum bending moment tolerated by nonprotected free-head piles was more than that by fixed-head piles. Also, reductions in bending moments were more significant in free-head piles in the presence of protection piles than in fixed-head piles. The bending moments of front and rear piles under restricted pile head conditions were reduced by about 31% and 21%, respectively, when finned piles were used as protection piles, while they were 34% and 42%, respectively, under free-head conditions. Furthermore, modification factors of recommended lateral pressure distribution along a pile per the current design code were determined for the protected and nonprotected free- and fixed-head pile groups of the current study and it was observed that this modification factor (CL) was highly dependent on the location of piles in a group, pile head conditions, and the presence of protection piles in the lateral spreading analysis. [ABSTRACT FROM AUTHOR]