Experimental Study On Bearing Capacity Of Foundation In Heterogeneous Soil

The bearing capacity of foundation is an important problem in geotechnical engineering.The present bearing capacity theory is mostly based on the assumption of homogeneous soil layer.Due to the interaction of physical or chemical factors,soil properties vary greatly in spatial distribution,which will bring a lot of uncertainty to geotechnical engineering analysis and design.The research on failure mechanism based on the spatial variability of the soil and the bearing capacity problem has made many achievements in theoretical analysis or numerical simulation methods.However,validation of these results is always a difficult problem,this is mainly because of the spatial variability of soil preparation is difficult.In this study,the bearing capacity and failure mechanism of soil foundation are studied for heterogeneous soil.This study used four kinds of water content in soil samples for heterogeneous soil preparation.The heterogeneous soil preparation scheme and test device are designed to meet the random field strength distribution,and the indoor preparation and test of heterogeneous soil are realized.In this paper,a vertical loading system,which is consistent with the size of the model box,is designed and manufactured to realize the indoor graded loading of the model foundation and the settlement displacement measurement of the soil.In addition,the whole experiment can obtain the soil deformation by using PIV technology.The indoor loading test of homogeneous soil and heterogeneous soil with different strength distribution is carried out respectively.The test results show that the failure mode of homogeneous soil is basically consistent with the classical foundation failure theory,and the soil deformation is symmetrical.The results verify reliability of the equipment system.The strength distribution of heterogeneous soil has a great influence on the deformation of foundation soil,and the failure mode of foundation becomes asymmetric during loading.The heterogeneous soil shows obvious difference from the symmetrical failure of homogeneous soil,and the soil deformation develops along the weak soil area.The numerical model corresponding to the loading test is established and analyzed by the stochastic finite element method.The results show that the foundation bearing capacity and soil deformation change are basically the same,and the difference is mainly caused by strain hardening of the foundation soil in the loading test.