使用强度折减法、Mohr-Coulomb破坏准则和有限元分析方法, 对岩体边坡在群桩施工前后、桥墩和桥梁施工时及运营荷载作用下的稳定性进行了数值模拟. 模拟时, 根据现有规范计算列车运营对桥墩顶部的竖向活载和制动力, 并根据岩土层分布建立了桥墩所在岩体边坡的3维几何模型, 研究了桥梁工程施工及运营的不同工况对岩体边坡稳定性的影响. 研究结果表明, 群桩施工前后边坡稳定性安全系数分别为1.35和1.63; 桥墩高度为6.0, 12.0, 18.0, 22.5 m时边坡稳定性安全系数分别为1.61, 1.60, 1.58, 1.57; 桥梁施工结束时及列车荷载作用下的边坡稳定性安全系数分别为1.55和1.53; 随着桥墩和桥梁施工荷载的增加, 岩体边坡中塑性区Mises等效应力逐渐增大, 边坡稳定性逐渐降低. 该结果对不同工况下岩体边坡中的桥梁工程设计和施工具有一定的参考价值.
Stability of a cutting slope at various stages, including those before and after the pile group construction, during the bridge construction, and under the train operation, were simulated using a strength reduction method, the Mohr-Coulomb failure criterion, and the finite element analysis technique. The existing specifications were used to simulate the live load and braking force of the pier top under the train operation. A three-dimensional finite element model was then established according to the practical locations of the geomaterials in the cutting slope. The influences of the loads on stability of the slope in bridge construction and operations were investigated. The study shows that the stability factors of the slope were 1.35 and 1.63 before and after the pile group constructions, respectively. The stability factors were 1.61, 1.60, 1.58, and 1.57 as the height of pier were 6.0, 12.0, 18.0, 22.5 m, respectively. In completion of the bridge construction and under the train operation, the safety factors decreased to 1.55 and 1.53, respectively. During the entire construction, the safety factors were decreased obviously. Nevertheless, the Mises stresses in the plastic zone increased as these safety factors decreased. The results presented herein may be used as references in the design and construction of bridges in a rock slope under various surrounding conditions.
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