Research On Non Ultimate Soil Pressure And Permanent Displacement Of Frame Prestressed Anchor Slope Under Earthquake Action

With the vigorous development of modern social civilization and science and technology,the infrastructure construction in the northwest region has also been vigorously developed.In slope treatment,frame prestressed anchor rods are widely used due to their advantages of convenient construction and good reinforcement effect.However,in recent years,earthquakes have occurred frequently,posing a serious threat to the safety of people’s lives and property.Therefore,it is of great practical significance to study the seismic performance of the frame prestressed anchor bolt support structure.In order to reduce the damage of the earthquake disaster to the frame prestressed anchor bolt support slope,it is necessary to conduct in-depth research on the earth pressure and permanent displacement it bears.This article uses the horizontal layer analysis method and the limit analysis upper bound method to study the non ultimate soil pressure and permanent displacement of frame prestressed anchor rod supported slopes under earthquake action,respectively.The following scientific research work has been mainly completed:(1)Through the systematic study and research of classical earth pressure,the shortcomings of classical earth pressure are found.Taking the slope of frame prestressed anchor rod support structure under seismic load as the research object,the relationship between the internal friction angle of soil and the friction angle between walls and soil affected by displacement under non limit state is established.By a ssuming the slope displacement of frame prestressed anchor rod support structure under seismic action,and based on existing theoretical research,the effective displacement area ratio method is improved,Apply the effective displacement area ratio to slope support structures with multiple displacement modes superimposed.On this basis,the horizontal layer analysis method is used to analyze the non limit soil pres sure under earthquake action.Based on the different movement trends of the soil behind the slope,a formula for calculating the non limit soil pressure of the frame prestressed anchor rod support structure under earthquake action is derived.The obtained formula is calculated using MATLAB,and the calculation results are compared and analyzed with the simulation results of finite element software.The results show that the distribution trend of soil pressure between the two is consistent,The rationality of this method has been verified.(2)On the basis of existing research on the sliding surface of slopes,this article assumes that the sliding surface of slopes is a logarithmic spiral,and constructs a model of frame prestressed anchor cable supported slo pes under earthquake action.Based on the upper limit theorem of limit analysis and the quasi-static method,the functional equations of slope internal force and external force work under earthquake action are obtained,and the calculation formula for seismic yield acceleration of frame prestressed anchor rod supported slopes under earthquake action is established,Using MATLAB programming software to program the theoretical formula,derive the formula for the permanent displacement of the slope of the frame prestressed anchor rod under earthquake action.Subsequently,using the parameters provided by a certain engineering example,theoretical formulas were used for calculation and compared with the finite element simulation results.The study showed that the theoretical calculation results were basically consistent with the numerical simulation results,ver ifying the rationality of the theory of permanent displacement of slopes.(3)Establish a slope reinforcement model of frame prestressed anchor rod support structure using the finite element analysis software PLAXIS 3D,determine soil parameters based on a certain engineering example,select a reasonable constitutive model,and consider the boundary conditions of the model under earthquake action.Add EI Centro seismic waves,simulate earthquake action by specifying the direction of slope displacement,and draw the seismic earth pressure and seismic displacement distribution curves of the reinforced slope with frame prestressed anchor rod support structure.The influence of different anchor pre-stress values and anchor spacing on slope soil pressure and displacement was studied.The results showed that under earthquake action,pre-stress is directly proportional to soil pressure and inversely proportional to slope displacement;The horizontal spacing of anchor rods is directly proportional to the displacement of the slope and inversely proportional to the soil pressure.