Study on the Stability and Seepage Characteristics of Underwater Shield Tunnels under High Water Pressure Seepage

Abstract

The construction of underwater shield tunnels under high water pressure conditions and seepage action will seriously impact the stability of the surrounding rock. In this study, an analytical model for the strength of the two-lane shield tunneling construction under anisotropic seepage conditions was established, and a series of simulations were carried out in the engineering background of the underwater section of Line 2 of the Taiyuan Metro in China, which passes through Yingze Lake. The results show that: (1) the surface settlement has a superposition effect, and the late consolidation and settlement of the soil body under seepage will affect the segment deformation and the monitoring should be strengthened; (2) under the influence of the weak permeability of the lining and grouting layers, the pore pressure on both sides of the tunnel arch girdle is reduced by about 72% compared with the initial value, with a larger hydraulic gradient and a 30% reduction at the top of the arch; (3) within a specific range, the tunneling pressure can be increased, and the grouting pressure and the thickness of grouting layer can be reduced to control the segment deformation; (4) the more significant the overlying water level is, the larger the maximum consolidation settlement and the influence range of surface settlement. This study can provide a reliable reference for underwater double-lane shield tunnel design and safety control.

An Efficient Seepage Element Containing Drainage Pipe

“…Seepage analysis holds crucial significance in civil and hydraulic engineering. The variations of pore pressure in soil can significantly affect the stability of engineering structures, such as slopes [1,2], tunnels [3], and earth-rock dams [4], etc., which are prone to collapse due to the rapid increase of pore water pressure during rainfall or floods. To mitigate the pore water pressure of soil and enhance the safety and stability of engineering, drainage pipes are often installed into embankments, underground structures, and slope engineering [5][6][7].…”