大断面地铁车站隧道软弱围岩渐进破坏规律模型试验研究

以贵阳市地铁2号线阳明祠车站为背景,采用室内模型试验模拟大断面地铁车站施工过程中隧道塌方破坏过程,明确施工期间大断面隧道塌方破坏过程机制,对比分析围岩和路面的变形。结果表明:通过围岩重力作用模拟隧道施工过程中塌方过程,与实际塌方过程基本吻合,弥补了常规加载破坏的不足;围岩渐进破坏过程表现为裂隙出现-裂隙发展-裂隙贯通-围岩塌方,支护渐进破坏过程表现为变形缓慢增加-变形快速增加-裂缝快速发展-支护破坏;围岩渐进破坏与支护渐进破坏相互作用,共同发展;在实际施工过程中,当支护变形大幅增加时,应增加支护强度,同时还应及时注浆、打设长锚杆,以减缓围岩裂隙发展,阻断围岩渐进破坏过程。

Model Test Study on Progressive Failure Law of Weak Surrounding Rock in Large Section Subway Station Tunnel

The process of tunnel collapse during the construction of large section subway station was studied by the indoor model test based on the Yangmingci subway station of Guiyang Metro line 2.The collapse process mechanism of large section tunnel during construction was defined,and the deformation of both the surrounding rock and pavement was compared.Results show that the process of collapse in the tunnel construction process simulated by the gravity action of surrounding rock is basically consistent with the actual collapse process,which makes up for the deficiency of the conventional loading failure.The progressive failure process of surrounding rock is shown as the appearance of fissure,the development of fissure,the penetration of fissure and the collapse of surrounding rock.The progressive failure process of support is shown as the slow increase of deformation,the rapid increase of deformation,the rapid development of fracture and the support failure.The progressive failure process of surrounding rock and that of support interact and develop together.In the actual construction process,when the deformation of support increases significantly,the support strength should be increased.At the same time,grouting and setting long bolts should be done in time to slow down the development of surrounding rock fracture and block the progressive failure process of surrounding rock.