Study on the Influence of Geological Fault Structure on the Energy Evolution of Rockbursts
摘要
This study investigated the damage characteristics and energy evolution laws of fault-induced rockburst based on the self-developed deep coal mine rockburst test system, equipped with micro-camera, acoustic emission (AE) and electromagnetic radiation (EMR) equipment. A damage test of fault structure sample and conventional sample under true three-dimensional conditions was carried out. The influence of fault geological formations on the damage characteristics of the roadway, and the law of AE and EMR energy evolution were analyzed. It was found that the presence of the fault structure caused more drastic damage to the roadway over a shorter period of time. During the total destruction period, the fault structure sample had a greater percentage of AE counts. However, the maximum AE counts, accumulative AE counts and cumulative absolute energy of the conventional sample were greater than the fault structure sample. The cumulative AE counts and absolute energy of conventional sample was 1.4 times and 2.0 times higher (respectively) than the fault structure sample, indicating that fault reduced the intensity of the rockburst energy release. Due to the existence of fault, internal friction occurred more easily, thus generating greater electric charge. The EMR phenomenon of the fault structure sample was more active than that of the conventional sample, and the maximum values of its EMR energy and amplitude were 1.6 times and 2.2 times higher (respectively) that of the conventional sample. The presence of faults allowed for easier rupture to occur inside the sample and increased the likelihood of damage occurring. This study provides theoretical guidance for the design of rockburst prevention for project sites with existing faults.