A Modified Spatial Mobilized Plane Constitutive Model And Its Experimental Verification For Cohesiveless Soil

In view of the deformation properties of soil under loads are very complicated,and are affected by many factors.so, the stress-strain constitutive relation of soil becomes a core problem in geotechnical engineering. But in geotechnical engineering, many questions belong to the space problem,Space destruction is usually in the form of shear failure, so wanting to solve to the geotechnical space damage, first is to solve geotechnical space failure surface position of the general formula of shear strength. For the space stress damage situation, position of geotechnical mobilized plane and how to determine the shear strength of the problem on space plane space have been didn’t cause the attention of many scholars, even very few in-depth studies. Based on the disadvantages of existing spatial mobilized plane constitutive model are analyzed, the modified spatial mobilized plane constitutive model is put forward and verified by experiment. Therefore, as the research object of this paper, has the important theory significance and engineering application value.Spatial mobilized plane constitutive model is a kind of constitutive mode,which can better reflect the strength and deformation characteristics of cohesionless soil. But because the model assumes that strain ratio and stress ratio of the spatial mobilized plane are linear relationship, leading which is not suitable for the low stress level、but also can not reflect the properties of soil tended to destruction. In view of the above defects, a modified method is proposed, and through conventional triaxial tests and plane strain test under the condition of true triaxial, verifying the reasonability of the modified model.This paper use cohesionless soil to do triaxial compression tests and plane strain tests, By collating and arranging the test data, relationship between stress ratio and strain incremental ratio curve and stress ratio and the shear strain ratio are drew. Analysis of the relationship between stress ratio with strain incremental ratio and shear strain, by test data to determine the four parameters of modified spatial mobilized plane constitutive model, the equation of modified spatial mobilized plane constitutive model is sure. Then compared under the condition of different confining pressure, of test results and calculation results. According to different confining pressure under the condition of triaxial test and plane test results, analysis of cohesive soils has been also stress-strain relationship and the volume change characteristics, etc.The main results geted from the paper are as follows: 1.The stress ratio and shear strain are corrected for the hyperbolic relationship on the spatial mobilized plane of the existing spatial mobilized plane constitutive, Through the analysis of the stress ratio and the shear strain relationship curve suggests:modified model is not only suitable for the possible range of whole stress and strain, but also can reflect the properties of soil tended to be destroyed with the increase of loading.2. Comparison the results of calculation model under various conditions with triaxial test and plane strain test results show that, This modified method in this paper is feasible.