Research on floor heave characteristics of broken soft rocks with high geostress and its comprehensive control measures

The problem of floor heave of high geostress broken and soft rock roadways, because of its complex geological conditions, is one of the technical problems of coal mining. Deformation and failure characteristics of floor heave of high geostress broken soft rock are analyzed; and the control measures are studied. The results show that, surrounding rock shows compressive shear rheological properties, supporting system should be regarded as a complete system; it focuses on not only surrounding rock repair, stress transfer and enlarged load ring, but also on exploiting the indirect effect of other parts of the supporting system. Comprehensive control measures integrating overcutting floor, high-strength cable, deep-hole grouting, bottom corner rockbolt, side bottom rockbolt and backfill are put forward. Numerical analysis model is established by using FLAC(3D); the changes of surrounding rock displacement field and plastic zones are analyzed while using the method; the validity of the method is verified. Comprehensive control measures applied to main roadways of Donger coal mining area, Paner mine, Huainan, makes a good supporting effect.