Experimental Study on Overburden Movement and Stress Variation of Coal Seam Mining with Associated Step Faults

Abstract

In order to study the special case of down-going coal seam mining accompanied by step faults, the upper and lower working faces and step faults of Chaili Coal Mine are used here as research objects. Overlapping rock movements and their correlation during the close-coal mining process are simulated by similar material simulation tests. The stress variation law was studied, and the research results show that: there is a crack structure and three broken forms in the overburden in single coal seam mining; there is a significant difference between “trapezoidal space” and “triangular space” in the overburden mining in the upper and lower coal seams; coal mining as a whole has the characteristics of “falling with digging, without obvious cycle to step, and difficult to form a beam structure”; and when there is a fault, the transmission of pressure is often affected by the stress barrier of the fault, and the closer it is to the roof, the higher levels of stress concentration.

Keywords

• close coal seam
• similar simulation
• step fault
• overburden failure
• stress change