The Change Regularity of Abutment Pressure under Various Propulsive Distance in Coal Face

Abstract

The application of UDEC software helps to simulate the changing regularity of the front and posterior abutment pressure and the pressure in the goaf within the scope of propulsive distance 220m in the coal face. Incorporating the Origin software the simulation analyzed the changes and correlation of the three kinds of pressure. We can see that when the propulsive distance is within 60m the change of the front and pressure is the same to the change of the back abutment and with the increasing of the pressure the posterior abutment pressure reaches its peak first. When the propulsive distance exceeds 60m the pressure of caving gangue in the goaf begins to increase and share some of abutment pressure. Each time the main roof collapses the concentration factor and the location of the peak of the front abutment pressure will fluctuate. The concentration factor fluctuates between 2.04~2.41 and the location of peak fluctuate between 7m to 10m. With the propulsive distance increasing, the posterior abutment pressure will tend towards stability when the propulsive distance is 140 m. The goaf which experiences the change trend of low pressure -high pressure -reducing to raw rock pressure has three areas: depressor area, pressurization area and stability area. The stress depressor area which is in the range of 10 to 20 m exists every 20 to 30m in the cut-hole and the gangue compacting area.