降雨作用下基于边坡位移速率稳定性评价

Stability evaluation based on slope displacement rate under rainfall action

摘要

虽然降雨对边坡材料强度的影响系数可以确定，但降雨条件下道路边坡的安全系数难以准确监测，可以监测的是边坡位移状况等因素。如果可以通过对此边坡降雨折减系数及边坡位移信息的评估，从而判断路基边坡的安全状况，实际工程中就可以根据安全状况及时进行支护，减少人员财务损失。以填土边坡为例，运用强度折减法，监测了边坡全局位移速率，分析建立边坡安全系数与监测点全局位移速率之间的关系。结果表明：强度折减法的具有可信性；均质路基填土边坡以圆弧形破坏为主，得到了边坡损伤变形破坏的全过程；边坡安全系数与位移速率是有关系的，通过分析边坡坡面上监测点位移速率与边坡稳定性状态之间的关系，所有点都基本一致，这也为评估边坡稳定性安全性提供了一定的依据；当位移速率小于8~10 m/s时，边坡出现局部失稳现象，坡脚位移较大，坡顶位移较小。此时边坡土体处于极限平衡状态，需要及时支护；当位移速率达到7~10 m/s时，边坡将整体失稳，沿圆弧形滑面滑动，此时所有坡梯滑动面内的监测点位移较大，且几乎没有相差无几，这说明该边坡出现了滑动。

Abstract

Although the influence coefficient of rainfall on the material strength of slope can be determined, it is difficult to accurately monitor the safety coefficient of road slope under rainfall conditions, and the displacement of slope can be monitored. If the safety condition of the roadbed slope can be judged through the evaluation of the slope rainfall reduction coefficient and slope displacement information, the actual project can be timely supported according to the safety condition and reduce the financial loss of personnel. The global displacement rate of the slope was monitored by the strength reduction method, and the relationship between the safety factor of the slope and the global displacement rate of the monitoring point has been analyzed. The result show that the strength reduction method is reliable; The damage, deformation and failure process of the homogeneous subgrade filled slope are obtained. The slope safety factor is related to the displacement rate. By analyzing the relationship between the displacement rate of monitoring points on the side slope and the stability state of the slope, all points are basically the same, which also provides a certain basis for evaluating the stability and safety of the slope. When the displacement rate is less than 8~10 m/s, the slope appears local instability phenomenon, the slope foot displacement is large, the slope top displacement is small. At this time, the slope soil is in the limit equilibrium state, and timely support is needed. When the displacement rate reaches 7~10 m/s, the slope will lose stability as a whole and slide along the circular arc sliding surface. At this time, the displacement of monitoring points in the sliding surface of all the slopes is large, and there is almost no difference, which indicates that the slope has slipped.

关键词

边坡变形速率 / 边坡稳定性 / 降雨折减 / 边坡破坏

Key words

slope deformation rate / slope stability / rainfall reduction / slope failure

Author summay

张俊平(1982—), 男, 高级工程师, 学士, 主要从事路基方向研究。E-mail: [e-mail]