THE RESEARCH OF CHARACTERISTIC FOR MINING COAL SEAM DEFORMATION AND SEEPAGE FLOW AFTER THE PROTECTIVE LAYER WAS MINED

Abstract

The low efficiency of underground gas drainage for high-gas coal mine mainly exists in the highland stress low permeability of most coal seams is the important parameters for the gas extraction degree of difficulty. Produce relief antireflection of the surrounding rock by using the coal seam mining, resulting in a substantial increase in the surrounding rock and its coal seam permeability coefficient in the exploitation of high gas seam group, which creates the preconditions for the high efficiency of relief gas drainage[1–4]. Therefore, in order to increase the coal seam permeability coefficient, the protective layer should be exploited first in the high gas outburst mine to make the coal body stress-state and the gas dynamic state change after the danger seam with highlight affected by mining, and make the large number of absorbed gas in coal or rock parse out, which contributes to the relief gas drainage after producing the relief effect. This article based on the geological conditions of Huainan Gu-qiao mine analyzes the overburden failure, flaw distribution and pressure relief coal seam horizontal and vertical displacement variation after the protective lager mining through RFPA2D-Gasflow soft ware, and comes to characteristics of pressure relief range and permeability variation for the protective layer. The research results provided a theoretical basis for the pressure relief gas drainage and drainage drilling design.