特大断面浅埋暗挖隧道十字岩柱开挖技术模型试验研究

Geomechanical model test on excavation technology of supper-large cross-section ultra-shallow tunnel with cross rock pillar method

特大断面浅埋暗挖隧道是一种新型隧道,目前尚无相应的设计施工技术规范与标准可循。以重庆市轨道交通3号线红旗河沟车站隧道为工程背景,结合以前施工方法的优缺点,提出了一种新的施工方法十字岩柱法。为了解这种施工方法在施工过程中隧道围岩位移和应力的变化情况,采用地质力学模型试验方法进行研究。试验对监测断面的位移和应力进行系统监测,全方位地了解各开挖步隧道围岩各处的应力与位移变化情况。选取工程背景现场的地质参数,采用ABAQUS软件建立数值分析模型,将数值计算与试验实测结果进行对比,两者的位移与应力变化规律基本一致,这表明模型试验实测的数据比较准确地揭示了隧道围岩位移及应力变化规律。其研究工作可对今后类似工程的施工提供经验和指导。

Recently, a new type tunnel emerges with these main feathers of super-large, cross-section and ultra-shallow. However, there are no relevant technical standards for the design and construction of the station tunnel at present. Taken Hongqihegou Station tunnel in Chongqing Metro 3rd line as the engineering background, a novel excavating method named the cross rock pillar method was developed by considering the advantages and disadvantages of the former methods of tunnel construction. A geomechanical model test was used to monitor stress and deformation of surrounding rock mass of the station tunnel during the process of excavation. The stress and displacement of surrounding rock were comprehensively analyzed during each step excavation. According to the geological parameters of the tunnel, a numerical analysis model was established based on ABAQUS software. By comparing monitoring results with numerical results, it indicates that the variation laws of stress and displacement are essentially the same. It is proved that the model test effectively reveals the variation laws of the stress and displacement of the tunnel. Therefore, this study provides valuable experience and useful guidance for the construction of similar projects in the future.