(1. School of Resources and Security Engineering,Central South University,Changsha,Hunan 410083,China;2. Beijing Construction Co.,Ltd. of China Railway Tunnel Group Shenzhen Metro Line 5 Landmark 5307 Projects,Shenzhen,Guangdong 518000,China)
Abstract:Subway tunnel ingate is the weak links of the tunnel structure. The construction under complex conditions easily leads to the collapse of vault and the settlement of ground and surrounding structures. Taking the Yijing road station to Huangbeiling station tunnel ingate project of Shenzhen Metro Line 5 for example,the construction techniques and monitoring methods are described. Construction experience and monitoring analysis show that:(1) because of using double-pipe grouting,hollow anchor grouting,big pipe shed and ductile grouting support methods,and constructing in accordance with monitoring results,the settlements of the ground and surrounding structures are controlled effectively;(2) double-pipe grouting reinforces the underground structures and the surrounding soil obviously;(3) big pipe shed construction is simple and rapid,and it can prevent the large area collapse of the vault,but the construction may lead to the water loss and ground settlement;(4) and the enclosure of lining structure is an effective method to control the horizontal convergence of the ingate section.