Study on Mechanical Characteristics of Tunnel Structure with Cavities Behind Linings in Arch

Abstract

Cavities behind the linings are common quality defects in tunnel construction, among which the cavities behind linings in arch are the most serious ones. Cavities behind the linings cause no contact between surrounding rock and supporting system, and also influence tunnel structure stress status. In order to obtain the structural force laws of the tunnel linings influenced by the cavities behind linings in arch, model tests, which include cavities with different sizes behind linings in arch, are designed to simulate the deformation characteristics, stress characteristics and failure modes. The test results are as follows: cavities behind linings in arch change the tunnel structure deformation and stress status dramatically; two cracks beside the cavities have formed as the loads grow; the cracked linings can also bear certain surrounding rock pressure. The test results can provide reference for tunnel site inspection and maintenance work.