Evolution of broken structure of hard thick roof and analysis of impact hazard area

Abstract

Aiming at the influence of hard and thick roof fracture and structural evolution on the impact of working face, taking the hard and thick roof condition of 63 upper 05 working face in Dongtan Coal Mine as the engineering background, the critical condition and structural evolution process of hard and thick roof fracture and instability are studied by theoretical analysis and numerical simulation, and the dangerous area of working face impact is divided. It is concluded that the thickness and strength of the roof are proportional to the vertical load at the end of the block breaking. The structure of immediate roof and main roof gradually evolved from “V” type to “U” type. The first and periodic steps of the double hard thick roof increase obviously compared with the conventional condition, and the evolution of the basic roof structure is more retarded than that of the direct roof. The vertical stress of the roof evolves in the form of stress arch, and many stress concentration phenomena are formed in the mined-out area during mining. Based on the above research results, the impact danger area of 63 upper 05 working face was divided and the accuracy was verified by microseismic monitoring technology.

Keywords

• rock burst
• hard and thick roof
• roof structure
• overlying rock fracture
• hazardous area classification