Behavior of Overlying Strata at the Working Face of in a Multi-fault Zone

Abstract

Fault is one of the common geological structures in coal mining, the concentrated development of several faults has changed the movement form and structure shape of overlying strata, which caused the instability of overburden strata easily and induced dynamic disasters. Taking the 10,416 working face of Yangliu coal mine as the research object, the plane numerical model of overburden structure with two faults (a reverse fault and a normal fault) was established by using UDEC numerical simulation software. The dip angle of normal fault is 50°, the dip angle of normal fault is 70°. The distances between the two faults are 30 m, 60 m, 90 m. The evolution characteristics of overburden structure in working face are studied respectively from hanging wall to footwall and from footwall to hanging wall, and the dynamic hazard law induced by the activation of different faults is analyzed. The results prove that: when the working face is mined from footwall to hanging wall, the overlying strata on the working surface form “trapezoid” and “triangle” structures. When the working face is mined from hanging wall to footwall, the overlying strata form the structure of “inverted trapezoid” and “inverted triangle”. The low-level fault activation caused by overburden movement is easy to induce dynamic response. Finally, the research results are verified by using the microseismic activity of 10,416 working face in Yangliu coal mine.