Abstract: According to deformation features and supporting problem of deep high-stress & broken- expand surrounding rock, with Qujiang Coal Mine as an example, optimization of secondary support parameter was studied. Concrete support projects were put forward based on deformation features of deep roadway and original supporting project, these projects include the first support parameters, the secondary support parameters and the secondary support opportunity. The piecewise linear strain-softening model was used to obtain post-peak soften strength parameters of surrounding rock. Strength effect of anchorage body was considered, the concept and the calculation formula of anchor supporting strength index (ID) was put forward, and modified calculation parameters of rock mass were given. Numerical calculation was done for these sixteen secondary support projects, and comprehensive scores index (ES) of roadway stability proposed was used to optimize projects. The results showed that the eleventh project (the anchor length (la) is 8 000 mm, the low and row distance (ea×ia) is 1000 mm ×1000 mm, the displacement value of secondary support opportunity (da) is 60 mm) can not only ensure stability of roadway, but also save cost, so it is optimum scheme. Therefore, influence relation of different anchoring effects and different displacement values of secondary support opportunity action on roadway stability were respectively analyzed, and overall evaluation and designing principles of support parameters were put forward.

Key words: deep high stress, roadway surrounding rock, support strength, secondary support opportunity, numerical calculation