Rectangular Piles Research Articles

The Influence of Pile Shaft Distributed Grouting on the Horizontal Load Response of Rectangular Piles

The Influence of Pile Shaft Distributed Grouting on the Horizontal Load Response of Rectangular Piles

Investigating the wave attenuation capabilities of rectangular pile head breakwater: A physical modelling approach

The study provides a comprehensive examination of single row Rectangular Pile Head Breakwaters (RPHB), encompassing both non-perforated and perforated variations. In the non-perforated RPHB category, the investigation delves into the effects of pile head height and width, and wave climate. For perforated RPHB structures, the study analyses the influence of percentage of perforations, perforation size, and depth of water. Further, the research includes a comparative assessment between non-perforated and perforated RPHB structures. Additionally, the research conducts a comparative analysis with similar structures. In the case of non-perforated RPHB, the configuration with relative pile head diameter (D/d) of 2.4 and relative pile head height (Y/Hmax) of 1.5 stood out as the most effective model. Similarly, the perforated RPHB demonstrated its maximum wave attenuation potential with percentage of perforations (P) of 24% with relative size of perforations (S/D) of 0.25. This optimal configuration achieved a minimal wave transmission coefficient (Kt) of 0.53, reflection coefficient (Kr) of 0.33, and energy dissipation coefficient (Kd) of 0.79 at a relative water depth (h/H) 0.865. Notably, the introduction of perforations on the RPHB structure led to an improvement in wave attenuation performance by 4–8%, resulting in lower reflection and higher energy dissipation. Comparatively, the RPHB structure outperformed the Enlarged (cylindrical) Pile Head Breakwater (EPHB) and Conical Pile Head Breakwater (CPHB) structures in terms of wave attenuation, exhibiting higher reflection and superior energy dissipation characteristics. The consistent outcome of these investigations reveals that the RPHB exhibits superior hydrodynamic performance characteristics and design suitability, making it a promising choice for breakwater applications.

Mathematical simulation of backwater and velocity distribution around tandem cylindrical piles

Nowadays, with the extensive development and utilization of coastal engineering, the research on the flow field around pile groups is becoming more important. In this paper, the flow velocity and water level distribution around tandem cylindrical and rectangular piles are calculated and studied by the numerical simulation method based on delft3D. The results show that the water level of the piles in the front row of the tandem pile group increases greatly, and the influence of the rear row of the piles is small due to the shielding effect.

Simplified calculation methods for earthquake-induced hydrodynamic added mass of immersed pile caps with different cross-sections

Assessment of the earthquake-induced hydrodynamic added mass of pile caps is important in predicting the seismic resilience of deep-water bridges with an elevated pile group foundation. Simplified formulas for the hydrodynamic added mass of immersed pile caps with different cross-sections were derived in this paper. The added mass values of circular pile caps with various dimensions and submerged depths were estimated based on the numerical fluid-structure coupled model, and the corresponding added mass calculation formula was obtained through the curve fitting method. The formulas to determine the added mass for rectangular pile caps and rectangular pile caps with fillet or chamfer corners were further developed by incorporating the corresponding shape coefficients for the pile cap in the formula. A total of 200 pile caps with different cross-sections and physical parameters were selected using Latin hypercube sampling to assess the performance of the proposed formulas. Next, the consistency between these formulas and the numerical model for added mass results was observed. The proposed formulas are concise and enable efficient calculation of the hydrodynamic added mass of pile caps submerged in water.

3D CFD Study of Scour in Combined Wave–Current Flows around Rectangular Piles with Varying Aspect Ratios

This study utilizes three-dimensional simulations to investigate scour in combined wave–current flows around rectangular piles with various aspect ratios. The simulation model solves the Reynolds-averaged Navier–Stokes (RANS) equations using the k–ω turbulence model, and couples the Exner equation to compute bed elevation changes. The model also employs the level-set approach to realistically capture the free surface, and couples a hydrodynamic module with a morphological module to simulate the scour process. The morphological module employs a modified critical bed shear stress formula on a sloping bed and a sand-slide algorithm for erosion and deposition calculations in the sediment bed. To validate the numerical model, simulations are conducted in a truncated numerical wave tank with the Dirichlet boundary condition and active wave absorption method. After validation, the numerical model is used to investigate the effect of aspect ratio and the Keulegan–Carpenter (KC) number on scour depth in a combined wave–current environment. The study finds that the normalized scour depth is highest for a rectangular pile with an aspect ratio of 2:1 and lowest for an aspect ratio of 1:2. The maximum normalized scour depth (S/D) for aspect ratios of 2:1 are 0.151, 0.218, and 0.323 for KC numbers 3.9, 5.75, and 10, respectively, whereas the minimum normalized scour depth (S/D) for aspect ratios of 1:2 are 0.132, 0.172, and 0.279. Additionally, the research demonstrates that the normalized scour depth increases with an increase in the KC number for a fixed wave–current parameter (Ucw).

A new method to select the cross-sectional shape of stabilizing piles from the perspective of design robustness

Stabilizing piles with different cross-sectional shapes, e.g., circular, rectangular, and trapezoidal, have been widely used in landslide treatment. Indeed, the selection of the cross-sectional shape of the stabilizing piles usually relies on a designer’s experience or a quantitative evaluation of the ultimate lateral resistance of the piles, considering the constant soil parameters. However, the observed uncertainties in the soil parameters may affect the estimation of the ultimate lateral resistance. Hence, a quantitative method, that considers the uncertainties in soil parameters, for the selection of the optimal cross-sectional shape for stabilizing piles based on the design robustness is developed in this study. An illustrative example is also presented to demonstrate and verify the proposed method. It is concluded that a rectangular pile has the preferred cross-sectional shape from the perspective of design robustness. The influence of the initial confining stresses, geometric parameters of the cross-section, coefficient of variation (COV) and correlation coefficients of the soil parameters on the selection of the cross-sectional shape is also further discussed. This work establishes a theoretical basis for the selection of the cross-sectional shape and provides further insights into the optimization of the stabilizing piles in landslide treatments.

Numerical analysis of laterally loaded barrette foundation

The effect of soil constitutive models, nonlinearity of the barrette material, loading direction as well as the cross-sectional shape and second moment of inertia on the response the barrette foundation under lateral loading is investigated in this research. The numerical analyses were conducted on a well-documented barrette load test using Plaxis 3D. The investigation results revealed that the response of the barrette is significantly affected by the direction of the applied load and nonlinear behavior of the soil and barrette materials. For rectangular, square, and circular piles with different cross-section areas and same second moment of inertia, the square and circular piles exhibit similar behavior but different from that of the rectangular pile. However, when these piles have the same cross-section area and different second moments of inertia, the behavior of rectangular pile is close to that of square pile when the load is applied along the x direction and is close to that of circular pile shape when the load is applied along the y direction.

Prediction of Undrained Lateral Capacity of Free-Head Rectangular Pile in Clay Using Finite Element Limit Analysis and Artificial Neural Network

Prediction of Undrained Lateral Capacity of Free-Head Rectangular Pile in Clay Using Finite Element Limit Analysis and Artificial Neural Network

Dynamic analysis of a laterally loaded rectangular pile in multilayered viscoelastic soil

Rectangular piles are usually used as the foundation for many infrastructures, but there are fewer theoretical solutions for the lateral vibration. This study presents a semi-analytical methodology for the dynamic analysis of laterally loaded rectangular pile in multi-layered viscoelastic soils. The pile-soil system is modeled as a continuum, the horizontal continuous displacement model is proposed as products of the separating variables function. The coupled governing equations for rectangular pile-soil system in the frame of Euler-Bernoulli beam and modified Vlasov model are derived with the aid of Hamilton's Variation principle and calculus of variations. The physical mechanisms of soil reaction and dynamic equilibrium equation are interpreted by employing thin-layer element of soil. The dynamic responses are solved analytically and numerically by an iterative procedure. The verification and accuracy of the research are obtained thorough comparison with the relevant examples from the literatures and finite element analysis. The effects of cross-section shapes and soil stratification on the complex dynamic response are investigated and discussed in detail.

Investigation on the feasibility of an alternative pile-sheet wall with circular piles for cutting slopes along high-speed railway

Pile-sheet walls (PSWs) have been widely employed to mitigate landslides on cutting slopes along high-speed railway in China. Piles in common PSWs are rectangular with large cross-sectional dimensions, which necessitate the use of manual methods during the excavation of pile holes. In this paper, a PSW with circular piles (PSWCP) is proposed to improve the safety and construction speed concerns associated with the traditional PSW with rectangular piles (PSWRP). Numerical analysis validated with a theoretical method was carried out to investigate the behavior of PSWs after excavation. The behavior of the piles was evaluated for several parameters, including pile diameter, length, spacing, and elastic modulus of pile material. The results of the parametric analysis indicated a similar response of both rectangular piles and circular piles. The safety factor of excavated slopes was employed as an indicator to evaluate the soil supporting performance of these two types of PSWs. Further, a critical line based on three-dimensional (3D) finite element (FE) analysis was developed to explore the feasibility of adopting PSWCPs. It became evident that PSWCPs present a viable approach to supporting cutting slopes along high-speed railway. Overall, this study provided primary insights into structural optimization of PSWs.

Scour effects on lateral responses of pile groups in clays

In contrast to single piles, pile groups experience more capacity loss by scour due to not only geotechnical group effect but also hydraulic group effect. However, existing standards only include design considerations for scoured single piles, and scour effects on lateral responses of pile groups are not fully appreciated. This study proposes a practical method to analyze lateral responses of pile groups in soft clays affected by local scour. The proposed method was verified against the results of 3D continuum finite element (FE) models, in which the baseline no-scour 3D FE model was established based on a reported full-scale load test. Parametric analyses were conducted to investigate the effects of scour-hole dimensions and pile group configurations on the lateral responses of pile groups in soft clays. The suitability of applying the methods specified in the various standards for a scoured single isolated pile to a scoured pile group was assessed by comparing them with the proposed method and 3D FE analyses. The results also highlighted the importance of the hydraulic group effect in the evaluation of lateral behavior of scoured pile groups. This research recommends a rectangular pile group shape with greater pile spacing in the foundation design against scour.

Group shape effects on the lateral capacity of pile groups in undrained soil

In this paper, the lateral limiting pressure on rectangular pile groups in undrained soil is explored using two-dimensional finite-element (FE) modelling. The primary aim of the study is to assess the influence of pile group shape effects on the soil limiting pressure offered by the deep ‘flow-around’ failure mechanism, and associated soil failure mechanisms, considering both a small (four piles) and large (36 piles) group. Additional parameters considered in the modelling include pile spacing and pile–soil interface roughness. The FE results show that group shape has a significant influence on the behaviour of closely spaced pile groups. In particular, the number of piles parallel to the direction of loading is shown to dominate the lateral bearing capacity factor such that significant increases in capacity efficiency can be achieved by slight modifications to the group shape for a given number of piles. The load-sharing across the group, traditionally defined using p-multipliers, was also shown to be highly non-uniform and dependent on group size, pile–soil roughness and group geometry in addition to the pile spacing. The FE output is presented in the form of design charts for the determination of group p-multipliers, whereas a library of existing design solutions is presented for the calculation of the overall group response.

Application of circular anti slide pile with plum blossom arrangement in Expressway Engineering

By using the finite element numerical simulation method, the simplified Bishop method and strength reduction method are used to analyze the stability of a high slope which is protected and treated by anti slide pile combined with prestressed anchor cable grading scheme in Guangdong Province, and the similarities and differences between rectangular pile and plum shaped circular pile in slope treatment effect are compared. Through calculation and analysis of field measured data, it is proved that the circular anti slide pile with plum shaped layout has similar effect with the traditional rectangular anti slide pile, and has the advantages of high degree of mechanization construction and low construction safety risk, so it can be used as the alternative scheme of rectangular pile

Effect of the proximity of slope and pile shape on lateral capacity of piles in clay slopes

The response of laterally loaded piles installed near the crest of clay slopes is analysed. Three-dimensional finite element analyses are presented for piles at various distances from a slope crest and for different pile shape. The results of these analyses are used to study the variation of the pile displacement, the bending moment of the pile and the soil resistance in relation to pile to slope distance and pile shape. The obtained results show that the proximity of slope significantly affects the lateral load capacity of the piles but not significantly when the piles are placed at 7D (where D is pile diameter) or greater from the slope crest. Furthermore, the lateral soil resistance on the ground surface for circular piles is larger than that for rectangular piles at the same lateral load in level ground. The decrease rate of lateral soil resistance on the ground surface for circular piles gets faster as the slope ratio and load level increase.

Behavior of single pile and pile groups in consolidating clay

As the pile group is commonly in use but the effect of consolidation times on the distribution of negative skin friction and drag force along the shaft of each pile in pile groups is still not well defined and studied. This paper presents the three-dimensional (3D) numerical analysis to study the behavior of a single pile and piles group consist of 3x3 piles embedded in a consolidated clay. Three-dimensional numerical simulation is carried out using Abaqus, a finite element software. Single circular piles and 3×3 circular piles in rectangular piles group with a spacing of 2.5D has chosen, where D is the diameter of circular pile. Based on the analyses, it is found that the location of the neutral plane is significantly influenced by the consolidation times. Results of this study showed that the maximum negative skin friction at 90 % degree of consolidations developed along the shaft of corner, side, and central pile compared with a single pile are 69%, 61%, and 45%, respectively.

Bayesian Updating Model for Structural Vibration–Induced Hydrodynamic Added Mass of Rectangular Pile Cap Submerged in Water

AbstractThis paper focuses on the calculation of the structural vibration–induced hydrodynamic added mass of the rectangular pile cap submerged in water. A total of 150 pile caps with different phy...

Modelo optimizado para cabezales rectangulares apoyados sobre un grupo de pilotes: Parte 1) Superficie óptima

Este documento muestra un modelo optimizado para cabezales o zapatas rectangulares apoyadas sobre un grupo de pilotes, con el fin de obtener el área de la superficie mínima en planta que soporta una carga axial y dos momentos en dirección del eje X y Y debido a una columna. Este modelo asume que los cabezales son perfectamente rígidos y los pilotes están articulados en la unión de los cabezales con los pilotes y, por lo tanto, los pilotes transmiten solamente carga vertical. La metodología normalmente utilizada para obtener el área de la superficie en planta de los cabezales se propone de acuerdo con la distribución de los pilotes, tomando en cuenta las especificaciones marcadas por los códigos de construcción. También, cinco tipos de cabezales apoyadas sobre un grupo formado por dos, tres, cuatro, cinco y seis pilotes se muestran para demostrar la exactitud del modelo presentado en este documento.

Seismic Performance of Various Piles Considering Soil–Pile Interaction under Lateral Cycle Loads for Integral Abutment Jointless Bridges (IAJBs)

The flexural pile foundation is used in integral abutment jointless bridges (IAJBs) in practical engineering to effectively dissipate the horizontal reciprocating deformation induced by the ambient temperature or earthquake loadings. Various types of flexural piles including the H-shaped steel pile (HP), prestressed concrete pile (PC), prestressed high-strength concrete pile (PHC) as well as the reinforcement concrete pile (RC) have been implemented in IAJBs. However, there is a lack of comprehensive studies on the flexural deformation and seismic performances of these piles. In order to investigate and compare their mechanical behaviors and seismic performances, a low-cycle pseudo-static test on several different types of piles was carried out. The test results indicated that the plastic hinge location of piles moved to a deeper pile depth with the increase of reinforcement ratio, buried pile depth and prestressing level, which led to better pile–soil interaction. The crack resistance of a concrete pile was improved as the reinforcement ratio and prestressing level increased. Moreover, the rectangular pile had a better soil–pile interaction and energy dissipation capacity than the circular pile. The inflection point of the pile deformation shifted deeper as reinforcement ratio, buried pile depth and prestressing level increased, which improved the effective length and horizontal deformation capacity of piles. The H-shaped steel pile showed a better elastic-plastic deformation capacity, ductility and energy dissipation capacity as compared to the concrete pile. Moreover, the pile having a higher bearing ratio sustained larger lateral loads whereas the surrounding soil was subjected to higher loads. Finally, new seismic design criteria of three-stage seismic fortification and five damage level for the concrete piles of IAJBs were proposed.

Analysing Rectangular Pile Using One Dimensional Finite Element

The traditional methods for analysing rectangular piles (Barrettes) are mainly modelling the barrette and surrounding soil using 3D-FE. 3D-FE for barrette foundations needs a huge computational effort. Consequently, a huge system of equations required to be solved. In this paper, a composed coefficient technique (CCT) is developed for analysing laterally loaded barrettes. The technique takes into account the three-dimensional full interactions between the barrette and the surrounding soil. In the technique, the three dimensional coefficients of the stiffness matrix of the barrette are decomposed to be one-dimensional. This enables easily adding these coefficients to those of stiffness matrix of the soil. Besides the practical application and efficiency of the technique, the nonlinear response of the barrette using any load-settlement relation can be considered. The technique may be al so applied for single barrette, barrette groups or barrette raft. A series of validations is carried out to verify the application of CCT for analysing single barrettes. It is found that treating the barrette by CCT, gives nearly the same results compared with the measured values from load tests and FE results. The proposed technique is implemented in the program ELPLA El Gendy M and El Gendy A (Analysis and design of raft and piled Raft-Program ELPLA, GEOTEC Software Inc., Calgary, 2019).

Linear analysis of a rectangular pile under vertical load in layered soils

In this paper, analytical and numerical solutions are developed for the pile with a rectangular cross-section under vertical load in layered soils. The rectangular cross-section is considered as a circular cross-section with a proposed formulation of equivalent radius. A number of bar elements models the pile and soil column below the pile tip while a series of independent springs distributed along the pile shaft with spring stiffness determined by properties of the corresponding soil layer models the surrounding soil. The method is based on energy principles and variational approach and the 1D finite element method is used in a pile displacement approximation. A new equation for modulus reduction appropriate for the rectangular pile is also developed to match the results of the proposed method to those of the three-dimensional (3D) finite element analyses. The proposed solution verified by comparing its results to the 3D finite element analyses and the comparisons are in excellent agreement.
 Keywords:
 rectangular piles; variational; energy principle; vertical load; finite element.