Study on technology of mine water disater prevention and control in underground mine under complex hydrogeological conditions

As for the current situation of mine goaf water accumulation caused by Dashihe passing through the water channel, in order to solve the problem of coal mine safety production caused by water accumulation in goaf, after investigating mine hydrogeological conditions, the reason of the increase of mine gushing water and the hazard of surface water to mine were analyzed. Moreover, multi-function grouting materials were used to block the water channel and strengthen the waterproof ability of coal pillar by ground curtain grouting and coal pillar reinforcement to eliminate the hidden trouble of mine water inrush caused by surface water, operating process and equipments were optimized in the engineering, and transient electromagnetic sensor and borehole peep were used to check the treatment effect. The results show that continuous high pressure water was formed due to the penetration between surface water and goaf in the small mine, which seriously affected the safety of working face mining. Multi-functional grouting materials were developed according to the engineering requirement. The material can be used by the water-cement ratio of（6.0～0.8）∶1.0，the setting time was 4～41min and the compressive strength was 0.84～18.70 MPa，and the various engineering requirements can be attained by adjusting water-cement ratio. The combination between curtain grouting and coal pillar reinforcement can enhance the coal body to strengthen the waterproof capacity of coal pillars and prevent the water inrush accident. By comparing the results of curtain grouting reinforcement detected by transient electromagnetic sensor, it was found that the electrical resistivity increased rapidly in the reinforcement area and the range of rich water area reduced，the apparent resistivity was increased from 5 Ω·m to 40 Ω·m. In addition, it was found by borehole peep that grouting reinforcement can better strengthen the broken coal bodies, slurries could backfill the fractures in the coal body and the effect was better. Safe mining in face was guaranteed by eliminating water inrush in uderground mine through grouting reinforcement.