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Abstract According to bearing capacity problem of a tunnel anchorage at Yichang side for Siduhe super-span suspension bridge，to study systematically the deformation and failure mechanism，the rheological characteristics and overloading capacities of the tunnel anchorage and its surrounding rock mass by a comprehensive rock mechanics research method are proposed. The approach included in the research consists of in-situ geological investigation，rock mechanical tests in laboratory and in the field，the 1∶12 anchorage physical model test with the same rock mass at site of the actual schemed tunnel anchorage，and the numerical simulations related to physical model test and the engineering analysis of bearing capacity evaluations of the actual tunnel anchorage. Several conclusions have been drawn. Firstly，the mechanical properties and the relevant parameters of the surrounding rock mass are obtained comprehensively by rock mechanical tests；and the physical model tests are quite reasonable compared to the actual monitoring results. Secondly，the total deformation of the actual tunnel anchorage is in the grade of mm with the designing load which will be supplied by the suspension bridge. Thirdly，the design requirement for the safety factor of the tunnel anchorage，which is greater than 4.0，is evaluated to be satisfied by the 1∶12 in-situ physical model test where the maximum anti-pulling force is carried out in the physical test，and ultimate tensile bearing capacity is greater than 7.6 times of the design load. At last，the permanent safety factor of bridge anchorage is not less than 2.6 according to the rheological observations in the physical test. The rock mass deformation and some relevant results have been verified through monitoring in process of the bridge construction. In addition，the technological line is an example for bridge construction in some other similar mountain areas.
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Received: 05 August 2009
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