A Research On The Spatial Distribution Feature Of Earth Pressure On The Flexible Retaining Structures For Soil Foundation Pit

This paper selected “monolithic wall” to analyze the distribution of soil pressure in different positions.It studied the distribution of the space earth pressure and the displacement by comparing the numerical simulation and indoor model test.It also studied the distribution of internal force of retaining structure and the relationship between space earth pressure and the displacement It have done the following work:1.It have reviewed the research results of the earth pressure distribution of retaining structure,including the analysis of the space earth pressure and the distribution of the two-dimensional earth pressure.Finally get the conclusion that the three-dimensional space earth pressure was more suitable for the deep excavation and the deformation law.2.It have done the indoor model test of relationship between spatial earth pressure distribution and soil deformation on the “monolithic wall”.Before the test,we optimized the thickness of the retaining wall and the excavation depth by using finite element analysis and the Venus analysis software.Then the distribution of earth pressure and displacement of retaining wall was measured.Finally we got the relationship between earth pressure and displacement of retaining wall,And got the distribution rule of bending moment of retaining wall by measuring the strain and stress of retaining structure.3.It carried out the finite element analysis of earth pressure and displacement in three-dimensional space by using finite element analysis software ABAQUS.Then we established the three-dimensional finite element model to simulate filling and excavation of foundation pit under 3D Structure.We studied the relationship between the distribution of earth pressure and the displacement of three-dimensional structure by studying the stress field following the excavation steps.And we also analyzed the law of the internal force of retaining structure with deformation.4.We got the law for the displacement and deformation of retaining structure by comparing the finite element numerical simulation and indoor model test result.It also studied the relationship between spatial real earth pressure and space additional earth pressure with the displacement by fitting the relationship curve of soil pressure.Main specific conclusion:(1)It showed the “R” type distribution in the vertical direction and the “positive parabola” type distribution in the horizontal direction.The earth pressure distribution law of the retaining wall presented the saddle shape.The earth pressure on both sides was greater than the middle earth pressure of the same height.(2)When excavation was carried out,active earth pressure gradually changed to active earth pressure state,but the passive earth pressure did not changed to passive earth pressure because of the unloading effect and the squeezing effect.(3)The maximum bending moment of retaining structure was near the excavation surface.Retaining structure of the maximum bending moment was also down development with the excavation depth gradually increased.(4)The additional earth pressure gradually increased with the increase of deformation,then we got the conclusion that the reason for the deformation of the retaining structure was the additional earth pressure rather than the actual earth pressure.