Calculation Of Horizontal Loaded Pile Based On Tangent Modulus Method

It is a complicated process of interaction between pile and soil to analyze the horizontal resistance,bending moment and displacement of soil on the side of pile.In many projects,the evaluation of horizontal bearing characteristics of pile foundation becomes a key problem to be solved urgently.Through the field horizontal static load test to evaluate interaction of piles and soil,the result,though reliable,but time-consuming,high cost;At present,the p-y curve method is the most widely used nonlinear analysis method for horizontal loaded piles in engineering and academia.Many scholars at home and abroad put forward the p-y curve function of clay and sandy soil according to the field horizontal test pile test,such as Matlock(1970),Reese(1974)and Reese&Welch(1975)respectively put forward the specific form of p-y curve in clay,sandy soil and hard clay.However,the existing p-y curves all rely on the undrained shear strength index Cu,and its value is easy to be affected by soil sample disturbance,so it is difficult to obtain accurate soil indexes in laboratory tests.According to winkler foundation beam model,a p-y curve method based on tangent modulus is proposed in this paper.This method takes into account the non-linearity between pile and soil,and can be used to calculate the displacement and bending moment of a single pile under horizontal load.The new method is analyzed and verified by theoretical analysis,numerical simulation and field test data analysis.This paper mainly completes the following work:(1)the theoretical methods of horizontal bearing characteristics of pile foundation at home and abroad are summarized,and the p-y curve method is analyzed with emphasis.Based on the concept of initial tangent modulus,a p-y curve method based on tangent modulus is proposed according to winkler foundation soil model.Each parameter required by the method is analyzed,and the specific steps to solve the p-y curve based on tangent modulus are determined.(2)using the Lpile software and the finite difference principle,the displacement and bending moment of a simple soil layer of sand,soft clay and hard clay were calculated respectively.The results show that the p-y curve method based on tangent modulus is suitable for a single soil layer.(3)carry out trial calculation through horizontal static load test of pile foundation carried out in typical pile foundation engineering sites in jiangsu province.The p-y(soil resistance-displacement)curve of the corresponding soil layer is obtained by analyzing and calculating the geological data of the site.The curves and soil conditions were input into the LPILE software to obtain the displacement and bending moment responses of pile under various loads.Meanwhile,the static load test was numerically simulated by using ABAQUS finite element software,and the horizontal bearing capacity of pile foundation obtained by theoretical method and numerical simulation method was compared with the field horizontal static load test result,so as to verify the applicability of p-y curve method based on tangent modulus in the case of complex bottom layer.