Numerical simulation study on asymmetric characteristics of surrounding rock stress in right angle trapezoidal roadway

The asymmetric deformation and failure of surrounding rock of right angle trapezoidal roadway in the inclined coal seam of Shitanjing No.2 Mine resulted in much difficulty to the stability control and support of the roadway. Based on this, the numerical simulation method was adopted to make a systematic analysis of the vertical stress, the horizontal stress and the horizontal displacement of roadways and the distribution and failure characteristics of surrounding inclined coal seam right angle trapezoidal roadway were given. The results show that there are obvious asymmetric stress concentration phenomena in the two sides, roof and sharp corners of the roadway which features a sharp differences between the stress concentration peak distances of two sides and the distances from the sidewalls；the stress grows as the inclination and ground stress increase when the inclination angle is 18° to 27°, the peak stress concentration of the low side is 1.07 to 1.33 times higher than that of the high side and the distance from the high side to the side wall of the roadway side is 1.26 to 3.79 m higher than the distance from the low side. Next, the two symmetrical sharp corners along the same direction of the coal seam are characterized by obvious compressive stress zones; by contrast, the two sharp corners in the opposite direction show obvious tensile stress. The maximum values of compressive stress and tensile stress appear at the two sharp corners of the roof of the roadway and its failures are characterized by severe deformation and damage on the low side and the floor plate.