Study of the Catastrophic Process of Water–Sand Inrush in a Deep Buried Stope with Thin Bedrock

Taking the 14,030 panel of Zhaogu No. 2 coal mine as its research object, this paper studies evolution characteristics developing height, propagation track and caving arch shape water-flowing fractures under influence thick alluvium by utilizing a physical experiment, theoretical analysis field investigation. The results show that height limit span fracture zone experience four stages, which include initial stage, slow-increasing sudden-increasing stage stable-increasing stage. With increase in mining range, overburden is gradually formed. water upper phreatic aquifer bedrock penetrate each other to form concentrated danger zone, expansion connects hydraulic connection between 2’s first seam. A large amount mixed with sandstone flows into surface bedrock’s broken rock block through fracture, leading instability load-bearing structure composed towering roof beam, illustrates whole process water–sand inrush accidents thin stope deep alluvium.