边坡地震稳定性分析探讨

传统的拟静力法和安全系数时程分析法在评价边坡地震稳定性时存在一定的局限性。在提出准确的评价边坡地震稳定性必需因素的基础上,建议对边坡地震稳定性分析方法重新进行分类。根据动力分析得到的边坡在地震作用下的破坏机制和破裂面的性质和位置,提出基于拉-剪破坏的动力时程分析法和强度折减动力分析法。第一种方法将FLAC计算得到破坏时刻的动应力施加到静力情况下边坡上,采用动力分析得到的拉-剪破裂面,结合极限平衡法求解边坡地震安全系数,是一种改进的动力有限元时程分析法;第二种方法考虑了拉-剪破坏的FLAC强度折减动力分析法,是完全动力的方法。最后通过算例分析验证了新方法的可行性,为边坡地震安全系数计算提供了一种新的思路。

Study on the seismic stability analysis of a slope

There exist some limitations when evaluating the seismic stability of a slope by traditional pseudo-static method and time history analysis method for safety factor. Based on the necessary factors to evaluate the seismic sta-bility of the slope accurately, the paper classifies the methods for analyzing the seismic stability of the slope. Ac-cording to the failure mechanism and location and property of the fracture plane of the slope analyzed by the dynam-ic program FLAC, the paper presents the dynamic time history analysis method based on tensile-shear failure and the dynamic analysis method of strength reduction. The former is to impose the dynamic stress during the failure calculated by FLAC on the slope under static, then to work out the tensile and shear fracture plane and to calculate the safety factor of the slope by combining the limit equilibrium method. The latter considers the dynamic analysis method of FLAC strength reduction of tensile and shear failure. This method is a complete dynamic method. At last, the paper proves the feasibility of the new method by analyzing the calculation examples and provides a new i-dea for the calculation of safety factor of the slope.