Abstract：
The construction of new tunnels can cause a redistribution of stresses in the surrounding rocks, which may pose a great impact on the adjacent existing tunnels. Based on the new Wudiao No.1 tunnel and Wudiao tunnel on the Pucheng-Meizhou railway, which approaches both the right and left sides of the existing Wudiao tunnel on the Xiangtang-Putian railway, this paper conducts a theoretical research, establishes an expression suitable for the impact degree on existing tunnel caused by construction of bilateral adjacent tunnels, and obtains two types of adjacent impact zoning based on the structural displacement criterion and the structural reliability criterion. By means of numerical simulation and regression calculation, two types of bilateral adjacent impact zoning are determined. And the results show that, compared to the adjacent impact zoning based on the structural reliability criterion, the adjacent impact zoning method based on the structural displacement criterion has a smaller range of strong impact zone and a larger range of weak impact zone. Corresponding construction countermeasures for the existing tunnel, new tunnels and intermediate soil pillars in different impact zones are put forward. Structural displacements and lining stresses in existing tunnel are monitored within the different impact zones. And the monitoring results show that when the suggested construction countermeasures are taken, the structural displacements and lining stresses in the existing tunnel could be well controlled, which is more affected by the new unsymmetrical loading tunnel on the left than by the new tunnel on the right.
WANG Zhijie1 LI Jinyi1 JIANG Xinzheng1 LI Zhen1 ZENG Qing2 WANG Ning2
.Research on the Impact Zoning and Construction Countermeasures for Bilateral Adjacent Tunnels with Shallow Depth and Unsymmetrical Load[J] MODERN TUNNELLING TECHNOLOGY, 2021,V58(4): 1-11
2021, Vol. 58 