贵阳轨道交通2号线省医站位于上软下硬的复合地层中.为了分析叠合初支拱盖法对本工程的适应性,本文采用数值模拟的方法,对施工可能引起的地表沉降、拱顶沉降、管线竖向位移、支护结构轴力和围岩塑性区分布进行了分析研究.结果表明:叠合初支拱盖法沉降控制效果理想、围岩塑性区分布范围和塑性应变值较小,但初期支护拉压区转换频繁,较为薄弱,易受破坏.与现场实测地表沉降数据对比显示,数值模拟结果在变化趋势上与实测结果基本一致,最终沉降量值也较为接近.因此,省医站主隧道选用叠合初支拱盖法进行施工合理、可行.
The Provincial Hospital Station of Guiyang Metro Line No.2 is located on the upper-soft lower-hard stratum. In order to analyze the adaptability of overlapping primary support arch cover method for the project, this paper adopts the numerical simulation method to analyze and study the surface settlement, vault settlement, vertical displacement of pipeline, axial force of supporting structure and plastic zone of surrounding rock caused by construction. Results show that the settlement control effect of overlapping primary support arch cover method is ideal, the distribution range of plastic zone and plastic strain value of surrounding rock are small, but the transformation of tension and compression zone of primary support is frequent, weak and vulnerable to damage. The numerical simulation results obtained by overlapping primary support arch cover method are consistent with the field data in terms of the change trend of surface settlement, and the final settlement value is also similar. Thus, the adoption of overlapping primary support arch cover method for the construction of the main tunnel of the Provincial Hospital Station is reasonable and feasible.
