上覆土层节理岩质边坡稳定性数值分析

摘要

The influence of the dip and inclination of joint and the ratio of soil thickness to rock thickness on the stability of jointed rock slope with overlying soil is researched in the present paper.The Mohr-Coulomb and Ubiqui-tous-Joint constitutive models and strength reduction method are used.Results of numerical simulation reveal that:for consequent-joint slope,when the consequent angle of joint is approximately equal to the internal friction angle of the rock,the safety factor is small and the damage area is large;while for anti-dip rock slope,the safety factor is large when the joint intersects vertically with the potential damage fracture of the slope.The effect of the dip of joint on slope stability reduces with the slope angle increasing.When the dip of joint is larger than the slope angle,slope angle is the main factor affecting the slope stability.When the thickness of soil layer is less than 4 meters,the slope safety factor increases with the thickness of soil layer increasing,and vise versa.When the thickness of the overly-ing soil is small,the slope toe should be the focus of support work,while the air side of the overlying soil should be supported as the key position when the thickness of the overlying soil is close to or larger than half of the slope height.%采用 Mohr-Coulomb 和 Ubiquitous-Joint 本构模型，运用强度折减法，研究节理面倾向与倾角、土层与岩层的厚度比例对上覆土层节理岩质边坡稳定性的影响。结果表明：节理面顺倾角度大小与岩体中岩石的内摩擦角接近时，坡体稳定性较差，破坏区域较大；节理面反倾角度与坡体潜在破坏裂隙近似正交时，坡体稳定性较好；随着坡角的增大，节理面倾角变化对坡体稳定性的影响逐渐减弱；当节理面倾角大于坡角时，边坡角度是影响坡体稳定性的主要因素；上覆土层厚度小于4m 时，安全系数随土层厚度的增加而增大，土层厚度大于4m 时，安全系数随土层厚度的增加而减小；上层土体的厚度较小时，应重点对坡脚处进行支护；上层土体厚度接近或超过坡高一半时，应重点对上层土体临空侧进行支护。