A NEW METHOD OF SEISMIC SLOPE STABILITY ANALYSIS BASED ON PSEUDO-DYNAMIC METHOD AND RESIDUAL THRUST METHOD

Due to the limitations of the commonly used pseudo-static method,combining the more reasonable pseudo-dynamic method with the slope limit equilibrium analysis method has important theoretical and practical significance for the analysis of seismic slope stability. Based on the pseudo-dynamic method and the residual thrust method in the limit equilibrium analysis,we derive the pseudo-dynamic seismic force calculation formula and the residual thrust calculation formula of the seismic slope considering the vibration amplification effect. On this basis,a program was compiled with the help of MATLAB software to calculate the residual thrust and safety factor of the seismic slope. A new method of pseudo-dynamic seismic slope stability analysis was obtained. Using the developed program,through the analysis of calculation examples,the influences of ground motion characteristics,slope material characteristics,slope geometry,and topographic amplification effects on the stability of seismic slopes were discussed. Research results indicate that the safety factor of seismic slope fluctuates periodically with the initial phase of the input ground motion,and the soil amplification factor does not change its fluctuation period. The safety factor of seismic slope decreases with the increase of the seismic coefficient,soil amplification factor,and the ratio of seismic wave length to slope height. Regardless of the vibration amplification effect,when the value of λ/H is equal to 2,the pseudo-dynamic safety factor changes from a sharp decrease to a stable. The smaller the value of λ/H,the closer the pseudo-dynamic safety factor and the static safety factor. The larger the value of λ/H,the closer the pseudo-dynamic safety factor and the pseudo-static safety factor. When considering the effect of vibration amplification,the pseudo-dynamic safety factor appears to be smaller than the pseudo-static safety factor. Therefore,the pseudo-dynamic method is more reasonable than the pseudo-static method from the perspective of safety or economy,and it is the preferred method for seismic slope stability analysis.