Experimental Study on the Law of Deformation and Fracture of the Coal Floor in Mining above Aquifer

Abstract

As the depth of coal mining in China increases, the dangerous break-up and the water inrush of the working face floor above aquiver show an increasing trend year by year. In this paper we investigate the working face floor of the Hedong Coalfield Shuangliu Coal Mine, and obtain the distribution characteristics of the aquifers under it by analyzing the hydrogeological data. We then employ a specially-designed working face floor water pressure simulation device to conduct simulation tests of the instability characteristics of the floor fracture during the mining process, and obtain the floor stress and displacement change laws for the working face. Finally, we employ the ‘plate model’ theory to calculate the maximum failure depth of the working face floor rock strata of the Shuangliu Mine. The results of the simulation test show that under the joint action of mining and aquifer water pressure, the floor failure regions are mainly concentrated in the coal walls and the area below the cut-holes, and the relief of the confined water pressure through mining can be simulated by using the new confined water simulation device.

Keywords

• Mining Engineering; Mining above Aquifer; Floor Failure; Simulation Test; ‘Plate Model’ Theory