框架预应力锚杆支护边坡地震动稳定性分析方法

摘要

Under the situation of considering the anchor prestress effects on stability of loess slope,according to the damage of the sliding surface,stability model of slope supported by frame with pre-stressed anchors under earthquake was established.By the method of lumped-mass explicit finite element,the soil was separated into soil-static-dynamic micro-unit and soil-prestressed micro-unit discretely,and the corresponding discrete element dynamic equilibrium equation was established,the displacement response and the stress field in sliding surface of the supporting slope were deduceed.Based on the displacement response and the soil stress field,a calculation method of stability safety factor for slope supported by frame with pre-stressed anchors under earthquake was proposed.A project example was analyzed by using the method proposed in this paper,the result was compared with the one of the quasi-static method.Comparison results show that the method proposed in this paper for the homogeneous loess slope is feasible,the earthquake reaction of the supporting loess slope and the dynamic performance of the soil can be showed primely compared with pseudo-static method.%在考虑锚杆预应力对黄土边坡稳定性影响的情况下,根据土体边坡滑移面的破坏模式,建立了框架预应力锚杆支护边坡的地震稳定性分析模型。利用集中质量显式有限元法,将土体离散为土体静动力微元和土体预应力微元,并建立了相应的离散动力平衡方程,推导了边坡在地震作用下的位移反应和滑移面上的应力场。基于位移反应和土体应力场,提出了框架预应力锚杆支护边坡在地震作用下的稳定性安全系数计算方法。用本文方法针对某一工程实例进行分析,并与拟静力法的结果进行比较。比较结果表明,本文方法对于土质均匀的黄土边坡是可行的,相比拟静力法,更能反应黄土支护边坡的地震作用和土的动力特性。