基于卸荷模拟开挖的地下厂房稳定性分析

Analysis of Stability of Underground Workshop based on Unloading Excavation

根据现场地质条件,对地下厂房工程进行了开挖卸荷模拟,分析了围岩的变形、应力状态和塑性区分布。根据模拟结果,地下厂房开挖后,围岩稳定性良好。受开挖和结构面空间组合作用,上游边墙、下游边墙和顶拱变形量分别在32—60 mm、25—43 mm和10—18 mm之间;变形主要发生在2—4级开挖步;1 584—1 602高程对围岩的稳定性影响最大;在厂房工程布置的监测仪器所测试结果和数值模拟具有良好的一致性。

Based on an analysis of engineering geology conditions of underground Plant, the 3 - dimendional distinct element numerical model is established. The excavation and reinforced process underground workshop are analyzed by using numerical simulation. The pattern of deformation, stresses state, distribution of plastic regions caused by excavation and influence factors of cavern surrounding rock are researched. Several conclusions are drawn; the whole stability of excavated and reinforced surrounding rock is good according to in site calculation conditions; the displacement of upstream walls is about 32 - 60 mm, downstream walls is about 25-43 mm and the crown layer is 10-18 mm under excavation; the mostly deformation of cavern walls are completed from excavated to subsequent 2-4 excavation steps. The excavation phases from 1 584 to 1 602 m are important to stability of cavern walls. By comparing the results, the numerical simulation are well in accordance with the monitoring data obtained from the multi - points extensometers, which were installed in the underground factories engineering of hydroelectric power station.