Search

A modified strain wedge model for analyzing the lateral response of reinforced concrete piles in sand is proposed in this paper. To address the limitations of the strain wedge model, the relationship between the lateral displacement of the pile and the soil strain is modified. This modification comprehensively considers the effects of the global compression of the soil and the local angle of the pile on the soil strain. The validity and accuracy of the proposed model are verified by published centrifuge test results and field test results. Finally, the effects of pile materials, pile geometry, and pile head boundary conditions on the lateral response of reinforced concrete piles in sand are discussed. • A modified SW model is proposed to analyze the plasticity development of RC piles subjected to lateral load in sand. • The model modifies the relationship between pile displacement and soil strain using layer-by-layer area equivalence. • The effects of material, geometry and boundary of piles on the plastic behavior of RC piles are discussed using this model. [ABSTRACT FROM AUTHOR]

Revealing lateral soil bearing mechanism around an offshore monopile is critical for understanding and solving soil-pile interactions. In this paper, the lateral bearing mechanism around an offshore monopile in sand is analyzed and a corresponding analytical method is established. Three soil bearing mechanisms, including wedge-type flow, triaxial extension and volume compression, near mudline under working load level are proposed by analyzing the distribution of the Lode's angle (θ L) and soil displacement vectors. A corresponding analytical method to calculate the lateral response of the monopile is developed based on the strain wedge (SW) model. The proposed model is verified through three pile tests. Finally, the effect of the parameters of Duncan-Chang model on the monopiles in dry and saturated sand is discussed. • Wedge-type flow, triaxial extension, and volume compression around a laterally loaded monopole are clarified. • The reasons for the formation of the three soil bearing mechanisms are explained. • A simplified analytical method considering the three soil bearing mechanisms is established to calculate monopile behaviors. • The clarification of the soil bearing mechanisms is useful for understanding and solving soil-pile interactions. [ABSTRACT FROM AUTHOR]

Piles are inevitably installed on sloping coastlines or inclined seabeds to support offshore wind turbines, offshore bridges, and other structures. The objective of this paper is to develop an analytical method for investigating the lateral response of short piles near clay slopes. The soil-pile interaction is modelled by a two-spring model which is used to describe the soil resistance around the pile and the horizontal shear force at the pile base. Considering the combined effect of slope angle and near-slope distance, the ultimate soil resistance along the pile is divided into three cases based on the nearby soil flow mechanism. The soil-pile-slope surface deformation mechanism is established according to the rotational deformation characteristics of short piles. In contrast to the modification of the initial stiffness, the p-y curve around the pile is constructed by considering the deformation mechanism. The accuracy of the analytical method is verified by comparing its results with two piles on level ground and five piles near slopes. Considering the soil-pile-slope deformation mechanism, the secant stiffness of the p-y curve is automatically adjusted and reduced without the need for additional numerical simulations or pile tests to determine the reduction factor of the initial stiffness. • A method is proposed for the analysis of laterally loaded short piles near clay slopes. • The method considers both the soil flow mechanism and the slope surface deformation mechanism. • The slope surface deformation mechanism is introduced into the framework of the p-y curve. • The framework automatically adjusts and reduces the secant stiffness of the p-y curve. [ABSTRACT FROM AUTHOR]

The nonlinear response of horizontally loaded piles located at the crest of offshore cohesionless soil slope is analyzed, based on the failure wedge model (FW) with variational base angle, in this study. The pile deflection differential equation considering the three-dimensional friction effect is derived; the failure wedge model with the variational base angle on slope crest is proposed; the three-dimensional friction effect along the pile on the failure wedge is considered; the calculation formula for ultimate soil resistance around pile on cohesionless soil slope crest is derived. The feasibility of the proposed method is proved by comparing the theoretical results with the test results. Finally, the slope effect and friction effect along the pile on laterally loaded pile behavior and the influence of pile diameter on the friction effect are analyzed and discussed based on the proposed method. Slope can weaken the soil resistance around the pile, while friction can strengthen that around the pile. The friction effect gets more significant with the increase of pile diameter. • The pile deflection differential equation considering three-dimensional friction effect is derived; the failure wedge model with variational base angle on slope crest is proposed; the three-dimensional friction effect along the pile on the failure wedge is considered. • The nonlinear response of horizontally loaded piles located at the crest of offshore cohesionless soil slope is analyzed with the proposed method. • The slope effect and friction effect along the pile on laterally loaded pile behavior and the influence of pile diameter on the friction effect are analyzed. [ABSTRACT FROM AUTHOR]

This paper develops a method for calculating nonlinear lateral response of offshore rigid monopile in sand under slope effect. The method modifies three-dimensional wedge failure model to evaluate the ultimate soil resistance in front of the laterally loaded rigid monopile near sloped ground. The modified model considers the ultimate horizontal frictional resistance, the slope effect, the vertical friction force, the mutual influence of the forces within the wedge. And the base horizontal shear resistance is considered in the method. In addition, the load-displacement curves of the rigid monopile under five different distribution modes of the soil reaction along the pile are calculated by the force and moment equilibrium equations. The method in this paper is verified by comparing its results with those of field test, 3D FE model, 1g laboratory model test and existing analytical methods. Finally, this method is used to study the rotation behavior and lateral response of the offshore rigid monopile. • This paper considers different wedge failure models to evaluate the ultimate soil resistance in front of the monopile (p u f ) located near slope in sand. • The improved wedge failure model account for the ultimate horizontal frictional resistance, the vertical friction force, the slope effect and the mutual influence of the forces within the wedge. • A method for calculating the response of laterally loaded rigid monopile under slope effect is proposed, which can account for different levels of lateral response of offshore monopile. • The base horizontal shear resistance of pile bottom and its bending moment are also considered. [ABSTRACT FROM AUTHOR]

This paper proposes a method for nonlinear analysis of a rigid pile under lateral load at the crest of clay slope. It is assumed that the ultimate soil resistance in front of the pile and behind the pile vary nonlinearly with depth. The modulus of horizontal subgrade reaction in front of the pile and behind the pile vary nonlinearly with the pile displacement at ground surface. The horizontal shear resistance at the pile base is considered and a bilinear relationship between the shear resistance and the displacement is used. Three distribution patterns of the soil resistance along a pile are also considered. Based on the force and moment equilibrium, the system equations are derived for a laterally loaded rigid pile in sloping ground with different soil resistance distribution patterns. The proposed method is validated by comparing its results with those from field tests, finite element analyses and a theoretical method. Finally, the method is used to analyze the effect of slope angle, pile-soil adhesion factor, height above ground surface of point of load application, pile diameter and embedded length on the lateral response of rigid piles. [ABSTRACT FROM AUTHOR]

Seven soil-pile interactions and four change processes of soil-pile interaction are proposed to predict the deflection of large-diameter monopile near undrained clay slope under a lateral load in this paper. The equations of force and moment are established in each soil-pile interaction, and the predictive load-deflection curves are obtained by solving those equations. The effect of slope and near-slope distance on the p – y curves is considered. The relationship between ultimate soil resistance and depth is divided into two forms according to the near-slope distance, and the ultimate soil resistance varies nonlinearly with the depth. The modulus of horizontal subgrade reaction in front of pile and behind the pile vary bi-linear and constant with the depth, respectively. To evaluate the accuracy of the new method, it is compared with the results of field tests and the finite element analysis. Finally, the method is used to analyze the effect of slope angle, near-slope distance, pile-soil adhesion and base resistance on lateral deflection. [ABSTRACT FROM AUTHOR]