An Experimental Study And Numerical Analyses Of The Relationship Between Additional Earth Pressure And Displacement For Retaining Structures

The magnitude and distribution of the earth pressure are related with the displacement of soil and retaining structures.The keypoints of the design theory for retaining structures,especially for excavation retaining structures are the correct internal relation of earth pressure and soil deformation,and the correct calculation of earth pressure on retaining structure s.When calculating theoretically the internal force and deformation of retaining structures,it was concluded that the displacement of retaining structure increases with earth pressure.A large number of engineering tests and numerical analyses showed that,on the side of foundation pits,the central retaining structures’ displacement is large,the total earth pressure is small,but the corner retaining structures’ displacement is small,the total earth pressure is large.The existing theory that the root cause of retaining structures’ displacement and so il’s deformation was the total earth pressure was debatable,while adopting additional earth pressure to calculate may be more reasonable.By adopting the combining method of indoor model test and numerical simulation,the relationship between the total earth pressure,the additional earth pressure,and displacement of retaining structure are studied.The main work is as follows:1.Earth pressure and displacement of retaining structure existing research results were summarized,and proposed that lateral deformation of soil and retaining structures should be caused by the additional earth pressure rather than the total earth pressure.And the additional earth pressure should be adopted for the calculation of retaining structure and soil displacement.2.In door model tests of the relationship between earth pressure and displacement for the retaining structure was conducted.According to preliminary analysis results in the phosphor software,the thickness of the soil retaining plate and the excavation depth of foundation pit was determined.Layered digging simulating excavation tests were carried out.In model tests,the earth pressure and displacement of retaining structure was measured,the bending moment of retaining structure was calculated.The earth pressure a nd displacement of retaining structure,the size and distribution of bending moment were studied.Earth pressure changing with the displacement was discussed.3.Finite element numerical analyses were carried out.A plane finite element model was established based on nonlinear finite element software ABAQUS and the simulation of excavation process were based on sand as filler.The numerical analysis about the earth pressure and displacement of the flexible retaining structure in the case of plane strain was done.How stress field and displacement field changed with the progress of the excavation was discussed.The law of earth pressure varying with displacement was in analysis.4.Compared the measured values and numerical results,it was showed that displacement of retaining structure and soil was consistent which met deformation compatibility principle.The curve of additional earth pressure and displacement was plotted and the stress path of different points in different regions was extracted.The formula for earth pressure considering displacement was received by function fitting.And the relationship between the total earth pressure,additional earth pressure and displacement was discussed.5.A finite element model was set up.The numerical simulation of rigid retaining structures under different displacement modes was carried on.The size and distribution of earth pressure of rigid soil retaining structures and the change of earth pressure along with displacement were analyzed.In addition,the relationship between the total earth pressure,additional earth pressure and displacement was discussed.The rationality of formula for earth pressure considering displacement was further confirmed.