Research On Pile-soil Interaction Of The Deep Cover

With the development of the hydropower cause in China,the major hydropower stations began to develop to the central and western regions,especially in south-west area which offers convenient condition for water and electricity exploitation.The geological conditions in these areas are very complex,and they are mainly based on coarse grained soil.Therefore,how to simulate the interaction between coarse grained soil and pile has become an important research topic.Using ANSYS to simulate the coarse grained soil foundation is simple and easy to implement,and is widely used in the study of the interaction between pile and soil.Among them,Drucker-Prager model(D-P model)and Duncan Chang model are widely usedHowever,the D-P model and Duncan Chang model have some limitations,they cannot accurately simulate body characteristics and Poisson’s ratio parameters of the coarse grained soil.Therefore,according to the mechanical characteristics of coarse grained soil,we used a modified Duncan-Chang constitutive model and analyzed the comparison of three axis simulation calculation and simulation of pile and soil through the D-P model and Duncan Chang model,and we have done the following research on the interaction between pile and soil in deep overburden layer.Firstly,according to the domestic and international research results,an improved Duncan-Chang constitutive model suitable for coarse-grained soil is selected and in combination with the DP model and the Duncan-Chang constitutive model to be the constitutive model of Pile-soil interaction in deep overburden in this paper.Secondly,by making full use of the user-programmable properties of ANSYS finite element software,we can got the secondary development of the Duncan-Chang constitutive model and the improved Duncan-Chang constitutive model.On the basis of the secondary development,simulation of soil triaxial compression test,respectively,show three different results and the results are compared with the results of triaxial compression tests.The contradistinction show that the modified Duncan-Chang model has a more reasonable result in the triaxial test of the coarse grai ned soil,which shows that the modified Duncan-Chang model has a better performance in describing the mechanical properties of coarse-grained soil.Finally,we used three different constitutive models to simulate the interaction between pile and soil in the coarse grained soil.The analytical results show that the modified Duncan Chang model is more reasonable,which further verify the applicability of the improved Duncan Chang model for coarse grained soils.In addition,we also analyzed the stress and strain characteristics of post pile soil by using of p-y method.This analytical method can provide some reference for the analysis and study of the soil pile interaction.This part is also the emphasis and difficulty of this paper.In the analysis of pile and soil,the applicability of the constitutive relation of soil to the mechanical properties of coarse grained soil is mainly considered,and the research results have important significance for the rational study of the pile and soil in the deep overburden foundation.