Mechanism and control technology of floor heave in deep high-stress water-rich clay soft rock roadway

In order to study the strong floor heave control technology of deep high-stress water-rick clay soft rock roadway, the floor heave mechanism of the main return roadway in the second panel area of Jiangjiahe coal mine was analyzed theoretically. UDEC-Trigon discrete element method was used to study the deformation and failure characteristics of the main roadway and the joint support mechanism of the floor bolting and grouting support. The deformation and failure characteristics of the main roadway and the mechanism of the floor bolting and grouting support have been studied. A new type of water-resistant anchoring agent suitable for anchoring bolts (cables) under water-rich conditions has been developed through laboratory experiment, and good results were achieved on site. Floor heave control scheme of grouting closed crack and anchor cable reinforcement was proposed and successfully applied in engineering practice.The research results show that the main return roadway exhibits squeezing fluidity and hydrodynamic expansion floor heave mechanism under the influence of high stress and hydraulic effects, and bolt-grouting support has no obvious effect for reducing the distribution of plastic zone in deep high stress surrounding rock, but can significantly control the generation of tensile cracks in the shallow part and the generation, extension and propagation of deep shear cracks to inhibit the formation of water-conducting fracture zones, and to prevent the surrounding rock from weakening the strength of the rock mass due to cementation. It can effectively improve the stress state of the surrounding rock of the floor, avoid the generation of near-zero stress regions in the shallow part and further release of deep surrounding rock stress. After the anchor-grouting support strengthens the floor,the anchor cable support system and the surrounding rock system of the floor are in a stable state, and the maximum floor heave of main return roadway is only 202 mm, which effectively controls the strong floor heave problem of deep high stress water-rich clay soft rock.