基于强度折减法的分步施工边坡稳定性分析

Stability Analysis of Staged Construction Slope Based on Strength Reduction Method

工程上常采用极限平衡法分析边坡的安全稳定性,但由于极限平衡法的局限性,使得计算结果只能反映边坡安全系数的大小,不能确定边坡在施工各个阶段的变形稳定情况,因此以永宁高速公路边坡为研究对象,通过PLAXIS有限元强度折减法对边坡施工过程中可能产生的变形、位移进行模拟分析,得到分步施工状况下,施工各阶段边坡的变形图以及整体的安全系数,并将结果与极限平衡法计算结果进行对比分析。结果表明:边坡的安全系数随着坡体的逐级开挖会不断降低,需及时进行支护加固,强度折减法所确定的边坡最终滑动面形状与极限平衡法计算结果较为一致,且安全系数差值仅为3%,从而也验证了强度折减法对于分步施工边坡安全稳定性分析的适用性与正确性。

The stability of slope is usually analyzed by limit equilibrium method in project,however due to the limitation of the limit equilibrium method,the calculation results can only reflect the size of the slope safety factor,and can^t de-temiine the defomiation stability of the slope at all stages of the construction.In this paper,by taking the slope of Yong Ning Expressway as the study object,the defomiation and displacement of the slope during the construction are simulated and analyzed by finite element strength reduction method of PLAXIS,and finally get the defomiation figure and entire safety factor of the slope at each stage of construction,and the results are compared with the results of the limit equilibrium method.The results show that the safety factor of the slope will be reduced with the step-by-step excavation of the slope,so it need timely support reinforcement.The final sliding surface shape determined by the strength reduction method is consistent with the limit equilibrium method and the safety factor difference is only3%,therefore the applica-bility and correctness of the strength reduction method for the safety stability analysis of the staged construction slope are also verified.