For an efficient and reliable evaluation of tunnel safety, it is necessary to understand the relationship between the ground condition involving discontinuity and the deformation pattern of the tunnel lining. In this study, the relationship between the ground condition and the deformation pattern is investigated by model tests in the laboratory and numerical analysis including the variables for discontinuity and stress condition. In the laboratory test, stress and displacement are observed with varying joint angle and stress condition through equipment in the size of 3 m x 3 m x 0.3 m. The angles of joint are varied with 0°, 30°, 45°, 60° and 90° and the ratio of the average horizontal stress to vertical stress (K) are 0.5,1.0,2.0 and 3.0. Using UDEC, DEM is carried out in the same condition and compared with the test results.The test shows that the characteristic patterns of the deformation of the tunnel lining can be related to the conditions of discontinuity and stress. Technical guides and tips for safety evaluation of the tunnels in service are drawn based on the results of the study, and the weak points of the tunnel which need an intensive observation during tunnel maintenance are also suggested.
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