Mechansim Of Deformation Of Soft Rock Roadway With High Horizontal Geo-stress And Its Supporting Measures

Supporting of the soft rock roadway is a complicated and important technology in the underground engineering field. As an important subject, soft rock roadway with high horizontal geo-stress is only studied a little, and so lots of supporting practice failed. It is of theoretical and practicable significance to study this subject. In this thesis, based on a lot of measurements, on-the-spot investigation, the engineering geological characteristics of roadway are summarized: fractured surrounding rock-mass; high strength of rock and low strength of rock-mass; high horizontal geo-stress and low vertical geo-stress; serious heaving of floor rock-mass, serious heaving of flank side of roadway, fractured roof of roadway. By lots of numerical simulations through FLAG program, laws of deformation and failure of soft rock roadway, with high horizontal geo-stress, are obtained: large deformation; long time of deformation; discrimination of different shape, dimension, geo-stress, flank coefficient; serious heaving of floor rock-mass. Then the mechanism of deformation and failure of soft rock roadway with high horizontal geo-stress is analyzed theoretically: Under high geo-stress condition, the inner stress is released and surrounding rock is bouncing after excavation of the rock-mass. The adjustment of geo-stress and deformation of surrounding rock are caused. Inverse tensile force is equivalent to in-situ-rock. So engineering rock-mass curves or slide of in-situ-rock moves to make strength of in-situ rock-mass lower to cause deformation of surrounding rock. Structural slides, was close, move because of bouncing of surrounding rock caused by releasing of geo-stress and dilation caused by adjustment of stress. With the change of stress status and strength of rock-mass, hydrological geology is changed also to cause rock-mass to dilate, the result is that large displacement and further failure happen.According to a lot of numerical simulations, basic supporting measures are selected to support soft rock roadway with high horizontal geo-stress, then special measures are given to achieve best result for soft rock roadway with different shapes, dimensions, geo-stress and flank coefficient. To engineering practice, measures can be selected accordingly, and it is very practicable to engineering practice. At last, it has proved by practice of Beijiao colliery of Sichuan province that mechanism and supporting measures are correct.