Analytical Approach for Face Stability Estimate of Tunnel with Pipe Roof Reinforcement
One of the most popular pre-reinforcement structures in the construction of tunnels through weak grounds would be the pipe roof reinforcement. This composite structure consists on installing, prior to the excavation of a length of tunnel, a series of pipes, either parallel to the tunnel axis or at a certain angle with it. By injecting grout through the pipes, the ground in between the pipes is stiffened and the pipes are connected, creating a kind of ‘umbrella’ above the area to be excavated. In this paper, by modifying the upper bound solution for tunnel face stability, the three-dimensional model for expressing the tunnel face stability with pipe roof reinforcement was established. For a typical example, the solutions computed by the proposed approach were compared with the results given by wedge model, trapezoid wedge model and centrifugal-model test to verify the reasonability of the method. It is shown that the calculation results of limit analysis are in close agreement with test results.
Chaohe Chen, Yong Huang and Guangfan Li
H. W. Song and H. T. Wang, "Analytical Approach for Face Stability Estimate of Tunnel with Pipe Roof Reinforcement", Advanced Materials Research, Vols. 243-249, pp. 347-350, 2011