Analysis of 3D deformation of tunnels under complex geological conditions

Field tests on 3D displacement at F7 fault and Silurian system strata at the ridge of Wushaoling tunnel were carried out and the test results were analyzed and compared with the 3D numerical results.By comparison of the average values,the 3D deformations at F7 fault and slate section were compared and analyzed,and were verified with the results of back-calculation of ground stress fields.It was shown that the 3D deformation in the tunnel at soft rock was obvious at F7 fault and phyllite section,with the characteristics of large deformation and longitudinal displacement developing in the opposite direction of work face and being stable at a distance about 2.0 times of tunnel diameter from the work face.And the 3D displacement of tunnels at F7 fault zone developed in an uneven symmetrical way,while there was good consistency for 3D deformation at slate section.Furthermore,there was a mutally verifying relationship between 3D deformation and ground stress distribution of tunnel region.Therefore it was necessary to carry out 3D displacement tests to detect the development of its deformation,and it would play a positive role in tunnel construction.