| Coal has long been the main source of energy in China and will continue to play a dominant role for a long time to come.Mine water damage is one of the main forms of disaster in the process of coal resources development.Exploring mine hydrogeological conditions and formulating scientific prevention and control programs play an important role in improving resource development efficiency,avoiding flood and reducing disaster impact.A number of main roadways in the-820 underground locomotive yard of Wanfu Coal Mine in Shandong province are arranged through 3# limestone.The initial exploration of 3# limestone in this area found that its hydrogeological conditions were complex,showing high water pressure and abundant water.Therefore,this project adopts data analysis,laboratory test,field test,numerical analysis and other methods to carry out a comprehensive study on the hydrogeological conditions of No.3 limestone in the area of the bottom yard of Wanfu Coal Mine-820 shaft,and based on this,formulate a water hazard prevention scheme of roadway.The main achievements of the project are as follows:(1)The hydrogeological conditions of the No.3 limestone at the bottom of the-820 m horizontal shaft in Wanfu Mine are studied mainly by means of water discharge test,and the permeability coefficient and water inflow per unit of the limestone are obtained.The water discharge test was conducted with 11 hole combinations and went through three test stages.According to the results of the water discharge test,the permeability coefficient of No.3 limestone in the vehicle yard area at the bottom of-820 well is 3.40 ～ 7.75m/d,and the unit water inflow is 0.036 ～0.276 L/(s·m).(2)According to the geological data and the results of the water discharge test,the thickness,occurrence,composition,strength and development characteristics of the dissolved fissure of No.3 limestone are obtained.It is found that the water richness and permeability of No.3 limestone are medium.It is easy to drain down.3#limestone is hydraulically related to 5# limestone,Neogene strata and Ordovician limestone,and the recharge model of 3# limestone is established.(3)Considering that the hydraulic relationship between # 3 limestone and Ordovician limestone is not close,and the 3 limestone is easy to drain down,the control design of water damage of # 3 limestone in x parking lot of horizontal well-820 m adopts the technical scheme of "drainage + plugging",which has the advantages of reducing the difficulty of grouting,reducing the grouting engineering amount,completely controlling the water of # 3 limestone,improving the working environment and improving efficiency.(4)Under the circumstance that the water pressure of No.3 limestone is greatly reduced,curtain grouting of No.3 limestone in roadway is carried out.The thickness of curtain grouting and the layout of borehole are determined,the grouting pressure is controlled reasonably by selecting cement grout,and the construction sequence of grouting hole is designed.After grouting,the roadway has been safely driven through No.3 limestone,without obvious outflow phenomenon,and the grouting effect is higher than expected. |
