Seismic Coefficient Of Slope Stability Analysis By Pseudo-static Method

China is located between the Pacific Ring of Fire and the Eurasian ring of fire,and has one of the highest earthquake incidence in the world.In the process of earthquake,it is easy to cause slope instability,resulting in a large number of casualties and property losses.Therefore,the evaluation of seismic slope stability is of great significance.In our country’s engineering practice,seismic slope stability evaluation is the most commonly used method is the pseudo-static method.Pseudo-static method to simplify the horizontal and vertical seismic force for constant inertia force does not change with time,according to Newton’s second law to solve the slope seismic force,the concept is clear,simple calculation.However,different values of seismic coefficients in pseudo-static method will lead to different seismic forces,which will affect the evaluation results of slope stability.At present,the existing seismic coefficient values are not uniform,the difference is large,and there is no solid theoretical basis to prove the rationality of the values.Therefore,the further research of the value of the coefficient is of important theoretical significance and practical value in engineering.In this paper,the slope is simplified as a right angle trapezoidal slope with a certain width.Based on the shear beam theory,the acceleration formula of the seismic response of the slope is derived,and the calculation method is solved using a Python program.On this basis,using a large number of actual ground motion data,the influence of the ratio(Rg)of slope response peak acceleration(PRA)to input peak ground motion acceleration(PGA)on slope height,slope angle,slope width,damping ratio,modulus of elasticity,predominant frequency of seismic waves,and input peak ground motion acceleration is analyzed.Finally,based on the comprehensive calculation results,the reasonable values of seismic coefficients corresponding to different earthquake intensities are given.The main achievements of this article are as follows:(1)Based on the theory of variable cross-section shear beams,an analytical calculation formula for the acceleration response of slopes under earthquake action has been established,and corresponding Python calculation programs have been developed.The formula indicates that the acceleration of slope response is mainly influenced by the characteristics of input seismic waves,the material and geometric characteristics of the slope;(2)The variation law of factors affecting slope response acceleration was analyzed using actual seismic data.The research results show that the relationship between input seismic peak acceleration and slope seismic response acceleration is the same increase and decrease,and the variation multiple is the same;The elastic modulus of the slope has the greatest impact on the seismic response acceleration of the slope,which increases first and then decreases,and determines the magnitude of the seismic response acceleration of the slope;The damping ratio is negatively correlated with the peak acceleration of slope response;The peak acceleration of slope response is negatively correlated with slope height and width,and positively correlated with calculated depth and slope angle;(3)Through regression analysis,a fitting equation was obtained between the slope amplification coefficient and the input seismic peak acceleration.When the input seismic peak acceleration was 0.05 g,0.1g,0.2g,and 0.4g,the amplification coefficients of the slope were calculated to be 1.62,1.42,1.22,and 1.13,respectively.Taking into account various influencing factors,the corresponding seismic coefficients for seismic intensities of VI,VII,VIII,and IX were determined to be 0.02,0.035,0.0625,and0.1125,respectively.