Analysis of Coal Floor Fault Activation Inducing Water Inrush Using Microseismic Monitoring—A Case Study in Zhaogu No. 1 Coal Mine of Henan Province, China

Abstract

Previously conducted studies have established that mining activities can activate faults, which will cause floor water inrush disasters and cause loss of personnel and property. In order to reduce the possibility of water inrush disasters in mining, it is particularly important to study the dynamic characteristics and rules of floor fault activation under the influence of mining. In this work, firstly, a microseismic monitoring system was established in the working face to analyze the changes of microseismic indexes before and after grouting. It was found that grouting can enhance the strength of a rock mass and play a role in sealing the water channel. Secondly, the quadratic kernel function of microseismic event energy was established. It was found that the accumulation degree of microseismic events and the region of high energy kernel density increased with the decrease of the distance between the working face and the left boundary of the “analysis region”. Combined with a microseismic event index and water inflow, the activation process of the floor fault was divided into five stages. Finally, the plastic failure region of surrounding rock under different excavation steps was analyzed by numerical simulation, and the characteristics of fault activation were further explained. A method of taking measures to prevent water inrush in the “sign stage of fault activation” was proposed.

Mechanism of and Prevention Technology for Water Inrush from Coal Seam Floor under Complex Structural Conditions—A Case Study of the Chensilou Mine

“…Liu et al [24] proposed a water inrush risk assessment method based on the failure characteristics of the floor above confined water and applied it to engineering examples. Some scholars [25][26][27][28][29][30][31][32] have applied numerical simulation methods to explain the mechanism of water inrush from floors containing faults, but most of them consider the impact of a single factor on water inrush. Mining operations on confined water and structural water inrush problems should be the result of the comprehensive effect of complex conditions such as the lithology, structure, and geological environment of the surrounding rock under the influence of mining effects.…”