考虑张裂缝的地震边坡屈服加速度计算方法研究

Computation method of yield acceleration of seismic slope with tension crack

传统边坡地震稳定性分析方法鲜有考虑土体拉裂破坏引起的张裂缝。基于极限平衡-拟静力法建立了水平地震力和竖向地震力作用下的力与力矩平衡方程,运用变分理论获得其临界破坏面及其对应的正应力分布,考虑土体没有抗拉强度建立考虑张裂缝的地震边坡屈服加速度的闭合解答。张裂缝的出现会显著降低地震边坡的稳定性,对于垂直边坡将达到50%。当边坡坡度较大时,竖向地震力向下作用获得的屈服加速度更小,当边坡坡度较小时,竖向地震力向上作用获得的屈服加速度更小。

According to the existing investigation of seismic slope failure, tension cracks occur easily at the top of the slope which seriously affects the stability of the slope.However, the traditional stability analysis of seismic slope seldom considers tension cracks caused by soil fracture.In this paper, the equilibrium equation of force and moment is established based on the limit equilibrium-pseudo static method.The critical failure surface and its corresponding normal stress distribution are obtained by variational method.A closed form solution for the yield acceleration of seismic slope considering tension cracks is established without soil tensile strength.The study shows that tensile cracks will significantly reduce the stability of seismic slope and it reaches 50% for the vertical slope ; The yield acceleration caused by the downward vertical seismic force is smaller when the slope inclination is bigger; In contrast, the upward vertical seismic force makes the yield acceleration smaller.