Analysis of the Influence of Support and Grouting Pressure on the Excavation Face of Upper Tunnel of Overlapping Tunnel on Lower Tunnel

Abstract

Based on the overlapping tunnel between Huancheng south road station and Kunming railway station in the first phase of Kunming metro project, the influence of excavation face support pressure and grouting pressure on the tunnel is studied.By means of finite element numerical simulation, the effects of soil chamber pressure and grouting pressure on the surface subsidence and the structural stress of the lining of the tube piece in the lower hole are analyzed.The study shows that the influence of grouting pressure is more significant, the shield driving should ensure that the excavation face support pressure is not less than the original horizontal stress of the stratum, and the grouting pressure should be controlled within the range of 0.8- 1.0 times the original stress of the stratum.