Analysis Of Finite Element About Compacting Effect Of Piles By Considering Dynamic Penetration Process

When piles are penetrated in saturated soils, on the one hand compacting displacements caused by soil compacting effect have adrerse effect on surrounding environment, seriously may cause accidents such as cracking of adjacent buildings、uplift of roads and underground pilelines break;on the other hand,after piles penetration,consolidation effect also improve the bearing capacity of the foundation,so making research on compacting effect have important significance.This paper condisers dynamic penetration process and analyzes compacting effect of piles and the bearing capacity of piles foundations affected by consolidation after piles penetration, mainly as follows:(1) Analyze the research status of compacting effect at home and abroad and clarify the research content further.(2) Introduce the solutions of undrained cavity expansion about the Tresca matericals based on total stress conditions and Modified Cam Clay matericals based on effective stress conditions,particularly analyze the solutions of compacting stress、compacting displacement and excess pore water pressure during piles penetration.(3) Analyze the key technology of compacting effect of piles simulated by finite element. adopting displacement penetration method with the actual process of piles,limiting the horizontal displacement through the center lines of piles by adding rigid pipe to pile endpoint as interface between piles and soils,but allowing cracking deformation of soils away from the center lines of piles in order to simulate the dynamic penetration of piles.According the results calculated by finite element,analyze the general rules of compacting effect and also compared with theoretical solutions;In additions,analyze the parameter sensitivity, discussing the effect of compacting displacements between different pile diameters and pile lengths.(4) Adopt finite element software to analyze the dissipation of excess pore water pressures and consolidation rules during penetration of piles in saturated soils,discussing the dissipation of excess pore water pressures、undrained strength development,and according to the bearing capacity of piles foundation theory to determine the value of the bearing capacity of piles foundations after piles penetration.