New Approaches For Calculating The Permanent Slope Displacement Based On The Pseudodynamic Methed And The Limit Equilibrium Methed

China,in the world,which is located between the Pacific Rim and Eurasia seismic belts,is one of the highest rates of seismic landslides.Slope instability during the earthquakes has caused lots of disasters.Therefore,the study of slope stability under earthquakes has significant theoretical significance and practical value.Currently,there are two main methods which evaluate seismic slope stability.One is to evaluate the stability of seismic side slope by calculating the safety factor of slope with the limit equilibrium theory.Another method is to evaluate the stability of seismic slope from the angle of permanent deformation.The latter can solve the situation that the safety factor is less than 1 when the former evaluates the seismic slope stability,but the slope is not unstable or damaged.The more reasonable method is the method of permanent seismic slope displacement.When determining the permanent slope displacement,Newmark’s sliding block methed invokes the pseudostatic methed to calculate the critical acceleration of the slope.This technique does not account for a time-varying seismic force,the propagation of seismic waves along the slope exerting infulence on seismic force and slope stability.Therefore,based on the basic principle of pseudo dynamic method,combining with Newmark’s sliding block methed,the Swedish slice methed,Simplified Bishop method,Sarma methed and the common circular slip surface,earthquake force calculation,seismic slope safety coefficient,permanent earthquake slope yield acceleration and the slope displacement formula were derived in this paper.Three approaches of calculating the permanent slope displacement were constructed using the pseudodynamic methed.On this basis,the corresponding calculation program was realized,and the influence rules of wave propagation effect,the horizontal and vertical earthquake acceleration effects on the permanent displacement of seismic slope were systematically analyzed.Finally,the results of the numerical simulation and the displacement calculation method based on the simplified Bishop method are compared and analyzed.At the same time,the paper analyzes the slope surface,slope body internal vertical direction,slope internal horizontal displacement change rule of different monitoring sites.Researchs are as follows:(1)Three new metheds which calculate the permanent displacement of seismic slope based on the pseudo-dynamic methed can reflect the wave propagation effect,which greatly improve the rationality of the calculation results.(2)With the increase of the frequency of earthquake,the permanent displacement of the seismic slope decreases.It accelerates with increase of the horizontal seismic acceleration,PGA,slope wave speed,slope height and slope angle.Actually,the displacement values coculated using the metheds of static force and the pseudostatic force represent the lower and upper limits of the permanent slope displacement calculated using the pseudodynamic methed.(3)The safety factor of the seismic slope increases with the increase of the vertical and horizontal ground motion coefficient ratio(SCR).The permanent displacement of the seismic slope decreases with the increase of the SCR.The vertical seismic acceleration can reduce the risk of the slope and the permanent displacement of the seismic slope.(4)Under the action of earthquake,the cohesive force and internal friction angle of the bottom structural plane of the rock slope have more influence on the displacement than that of the side structural plane.The cohesive force of structural plane has less influence on slope displacement than the internal friction angle.(5)The results of the numerical simulation and the displacement calculation methed based on the Simplified Bishop method in this paper are close to each other.The displacement changes with the slope parameters and ground motion parameters are consistent.(6)The seismic acceleration has a great influence on the horizontal and vertical displacements inside the slope under the earthquake action.The internal vertical displacement and horizontal displacement are lesser than the surface displacement.It embodies the slope amplification effect and the function of the open surface.Both internal vertical and horizontal displacement,the greater the distance from slope,the smaller the displacement,indicating that the farther from the slope surface,the surface effect gradually weakened until basically disappeared.