Research On The Earth Pressure Acting On Supporting Structure Considering Limited Soil Near River And Water Level

With the increasing shortage of urban land resources,more and more buildings have to be built near rivers and lakes,and the edge of the excavation pit is close to the river,forming limited width soil.At this time,if the earth pressure acting on the foundation pit support is still calculated according to the Rankine or coulomb earth pressure theory,it will be greatly different from the actual situation.In this paper,the study is focus on the earth pressure of support when the foundation pit is close to the river.The main work and conclusions are as follows:1.A calculation model is established for the finite soil between the foundation pit and the river,factors such as wall-soil interface friction,water level and riverbed angle are considered,and then based on the limit equilibrium theory,the stress of the sliding soil is analyzed.Assuming that the sliding surface is a plane,the formula for calculating the active and passive earth pressure of finite soil body is derived.The applicable scope of the formula is explored,and some special cases are analyzed according to the cut-off position of the fracture surface.Finally,the calculation formula for the earth pressure is summarized.2.The excavation of the foundation pit near the river was simulated by laboratory model test.The displacement of retaining wall and the distribution of earth pressure acting on it after each excavation and support.The angle of riverbed was controlled by a wooden model,and the height of water head in the river groove simulated the water level of the river.The influence of the distance from the river,the angle of the riverbed,the height of the water level and other factors on soil pressure acting on the support is explored.By observing,the failure mode of foundation pit is basically consistent with the calculation model,which further verifies the rationality of the calculation method in this paper.3.Finite element numerical analysis was carried out on the excavation of foundation pit under the condition of finite soil near the river.Using PLAIXS to simulate the excavation of foundation pit.The constitutive model of soil was hardening soil small model.The influence of soil parameters,distance from the river,water level height,riverbed angle and other factors on the pressure acting on the support is explored.The numerical simulation results are compared with the method in this paper and the previous methods,and the method in this paper is more consistent with the numerical analysis results.4.On the basis of theoretical analysis and numerical simulation,combined with the actual project,the actual displacement of the support and uplifts are compared with the results of numerical simulation,which proves the rationality of the numerical model,so the earth pressure can be thought is consistent with the actual value in a certain,study the distribution and compared with the result of calculation method,the overall trend is similar,and the theoretical value is slightly larger.