Study On Seismic Dynamic Response Of Silty Clay Slope Supported By Prestressed Anchor Anti-Slide Pile

In slope prevention and control engineering,earthquake action is the most important cause of slope failure.As a new type of supporting structure,prestressed anchor anti-slide piles can effectively improve the anti-seismic performance of slopes.Therefore,anti-slide piles with anchor cable are used for earthquakes.Dynamic response research is necessary.In view of this,this paper takes the G0512 line ChengduLeshan Expressway expansion construction project as the supporting project,and uses FLAC3 D finite difference software to carry out a numerical simulation study on the seismic dynamic response of prestressed anchor anti-slide piles supporting silty clay slopes.The dynamic response law under different working conditions are obtained.The research results have certain theoretical value and practical engineering significance.The main research contents and results are as follows:(1)Based on the related theories of slope support and using FLAC3 D finite difference software,a model of silty clay slope supported by anti-slide piles with prestressed anchor cables is established,and the dynamic response of the slope is analyzed.The results show that the acceleration peak amplification factor PGA,the peak velocity,the slope horizontal direction displacement peak and the final state value increase with the increase of the slope elevation.The PGA coefficient will increase suddenly on the sliding surface.At the same elevation,the monitoring data in the downhill is smaller than that in the slope.The peak dynamic earth pressure behind the pile,static earth pressure and final value increase first and then decrease with the decrease of elevation.After the earthquake,the bending moment of the pile body presents a “convex” shape distribution law with two small ends and a large center,and the pile body shear force presents an “S” shape distribution law.The axial force value of the free section of the prestressed anchor cable is basically unchanged,the axial force value of the anchoring section is reduced to zero at the end,and the final axial force value of the free section of the anchor cable is increased by 8.66% from the initial value.(2)Based on the correlation theory of seismic wave,the dynamic response analysis of silty clay slopes under different amplitudes shows that the greater the seismic amplitude,the greater the dynamic response of the prestressed anchor anti-slide pile and the slope,but the increase of earthquake amplitude gradually reduces the influence rate of slope acceleration,velocity,displacement and other indicators of dynamic response.(3)Considering the influence of soil parameters,the dynamic response of silty clay slopes under different cohesive forces and internal friction angles is analyzed.It turns out that the dynamic response of earthquakes to slopes supported by anti-slide piles with prestressed anchor cables decreases with the increase of soil cohesion or internal friction angle,and when the cohesion is 10 k Pa or the internal friction is 10°,the dynamic response of the prestressed anchor anti-slide pile and the slope increases significantly.(4)Based on the calculation theory of anchored piles and the theory of strength reduction method,the dynamic response analysis and the dynamic safety factor of the silty clay slope under different anti-slide piles embedded depth are analyzed.The result shows that the earthquake action affects the prestressed anchor cable.The influence of the dynamic response of anti-slide piles and slopes increases with the decrease of the anti-slide pile embedded depth.The dynamic safety factor of the slope decreases with the decrease of the embedded depth.When the anchorage length of anti-slide pile accounts for more than 38% of the total pile length,it can effectively reduce the impact of earthquake action on the dynamic response of prestressed anti-slide piles and slopes,and improve the dynamic safety factor of the slope and the stability under earthquake action.