Escaping mechanism of shield tail grouting and its model test during shield tunnelling surrounding rock stratum
ZHONG Xiaochun1, LUO Jinhai2, DENG Youchun2, FU Wei2
1. College of Civil and Transportation Engineering, Hohai University, Nanjing 210098, Jiangsu, China; 2. China Railway First Group Co., Ltd., Xian 710068, Shaanxi, China
Abstract When shield machine goes through the stable rock stratum, the backfilled grouting behind the segmental linings will inevitably escape along the gap between the shield shell and the stratum to the cutter plate and the excavation surface. Based on Bingham fluid, the theoretical calculation formula of the loss amount for the shield tail grouting escaping was established, and the relationship between the loss amount of grouting, the properties of grouting, gap thickness and grouting pressure was analyzed. The experimental models with different properties of grouting, gap thickness and grouting pressure for escaping of shield tail grouting were established and tested, and their results verified the rationality of the theoretical calculation formula proposed. Based on the formula for calculating the amount of escaping grouting of shield tunnel, the critical condition of the escaping grouting commonly occurred in subway tunnel construction was obtained, i.e. the relationship between the viscosity resistance of grouting and the thickness of gap between the shield shell and surrounding stratum. The findings can be expected to guide the preparation of grouting of shield tunnelling in stable rock stratum.
ZHONG Xiaochun,LUO Jinhai,DENG Youchun, et al. Escaping mechanism of shield tail grouting and its model test during shield tunnelling surrounding rock stratum[J]. Hazard Control in Tunnelling and Underground Engineering,
2020, 2(2): 58-65.
