Research on Water Drainage Schemes for Segments in High Water Pressure TBM Tunnels
Addressing the issue of large burial depth and high water head encountered in a certain TBM tunnel,three schemes are proposed:radial grouting for water blocking,symmetrical water drainage through inverted arch,and deep-hole water drainage,to reduce the water pressure borne by the segment lining.Theoretical calculations and numerical simulations are employed to evaluate the water drainage effects of the three schemes.The main conclusions are as follows:(1)Under such working conditions,relying solely on the protective capabilities of the segments and waterproof sealing gaskets cannot meet the safety requirements of the tunnel;(2)The radial grouting scheme for water blocking can effectively reduce water pressure.The design requirements are met when the thickness of the grouting layer exceeds 6 m.This scheme has no impact on the water pressure distribution of the surrounding rock,reduces the impact of tunnel excavation on the stress field of the surrounding rock,and ensures the stability of the surrounding rock;(3)When adopting the symmetrical water drainage scheme through the inverted arch,a thin permeable layer needs to be constructed between the grouting layer and the segments to allow water to fully collect at the drainage holes;(4)When adopting the deep-hole water drainage scheme,six drainage holes per ring of segments are sufficient to meet the drainage requirements of the segments when the drainage pipes extend 1.2 m beyond the outer surface of the segments.This scheme provides more uniform precipitation effects across the entire ring of segments and a higher structural safety factor.
Railway TunnelTBM TunnelHigh Water PressureDrainage Segments
万方数据
维普
