Construction method for sudden encounter of untreated karst caves or fractures during shield tunneling

Abstract

The invention provides a construction method for sudden encounter of untreated karst caves or fractures during shield tunneling. In the shield tunneling process, when the earth silo pressure drops orthe amount of excavated earth decreases, blended thick mud is injected into an earth silo, and then segments with reserved grouting holes are assembled in the tunneling process until shield parametersreturn to be normal, after the assembly is completed, through drilling holes in the segment reserved grouting hole positions in a pressure-loss area of the earth silo, the positions of the karst caves or fractures are detected, and check valves are installed at the hole positions, communicating with the karst caves or fractures, polyurethane slurry is injected, and after grouting is completed, the grouting position is subjected to hole expansion, sleeve valve steel pipes are buried, and cement slurry is injected into the water leakage position; and meanwhile, the ground is monitored at the pressure-loss position of the earth silo, and in areas with large settlement, WSS grouting reinforcement is adopted. According to the construction method, the thick mud is used for treating the karst caves, then the karst cave fractures are plugged by injecting polyurethane and the cement slurry and cooperating with the ground WSS grouting stratum reinforcement, and the problem of shield tunneling encountering untreated karst caves is effectively solved.

Description

technical field [0001] The invention belongs to the field of urban rail transit engineering, and specifically aims at a construction method for shield tunneling when it encounters untreated karst caves or cracks, so as to ensure that the shield tunnel can pass through the karst cave development area normally and ensure the safety of shield tunneling. Background technique [0002] As my country's infrastructure construction has entered a white-hot stage, urban rail transit construction has also followed the wave of infrastructure construction to continue to develop rapidly, and shield construction is also playing an increasingly important role in the subway construction process. In southern my country, Yunnan, Guangxi, Guangdong, Guizhou, Sichuan and other regions are greatly affected by karst, and it is inevitable that shield tunnels will pass through karst cave development areas. The construction of tunnels brings great risks. The development of karst caves not only serious...

AI Technical Summary

Problems solved by technology

Since the shield earth silo needs to be balanced with the earth pressure, if the shield tunnel encounters untreated karst caves or cracks during construction, the pressure of the earth silo will decrease, and even cause the ground to collapse, seriously endangering the safety of the excavation process.

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