含瓦斯煤岩真三轴多参量试验系统研制及应用

Development and application of true triaxial and multiparameter experimental system for coal rock containing methane

以深部日趋严重的煤岩体冲击-突出复合灾害为研究背景,紧密围绕多场条件下的煤岩流(瓦斯)-固耦合力学行为演化机制这一关键科学问题,充分考虑深部煤岩真三向应力环境与受载特点,自主研发了含瓦斯煤岩真三轴多参量试验系统,以期厘清煤岩受载、破坏过程力学行为、声发射与电荷感应信号时空演化规律,掌握冲击-突出复合灾害孕育力学机制,建立科学的灾害防控手段。该试验系统主要由加/卸荷系统、载荷-位移监测系统、气体环境施加与监测系统、电控系统、声发射监测系统、电荷感应信号监测系统6个子系统组成,具有高应力、真三向、多尺寸、高精度、稳定性强、多参量、多加/卸荷路径等特点。利用该系统初步开展了瓦斯压力、侧压比与卸荷路径影响的煤岩三轴受载试验,并对全应力-应变曲线及声发射、电荷感应信号变化规律分析。结果表明,瓦斯气体影响了煤岩强度、峰后残余强度及延性特征,随侧压比值降低煤岩各向异性特征逐渐弱化,在应力较小方向具有较大的应变量,侧压比与加/卸荷路径是影响煤岩力学行为的重要应力环境因素。该系统为后续开展含瓦斯煤岩力学行为时空演化规律研究提供了试验基础。

Based on the background of the increasingly serious composite disaster of coal and rock mass impact-outburst in the deep, and closely surrounding the key scientific problem of the evolution mechanism of coal-rock flow(gas)-solid coupling mechanical behavior under multi-field conditions, a true triaxial multi-parameter test system for coal and rock containing gas has been developed independently. The test system can fully simulate true three-dimensional stress environment and loading characteristics of coal and rock in the deep. It is hoped that the test system can clarify the mechanical behavior of coal and rock during loading and failure, the spatio-temporal evolution law of acoustic emission and charge induction signals, grasp the mechanism of impact-outburst compound disaster breeding, and establish scientific means of disaster prevention and control. The experiment system consists of 6 sub-systems, i.e. loading-unloading, load-displacement monitoring, methane environment application-monitoring, electric control, acoustic emission and charge induction. It has the characteristics of high-stress, true triaxial, multi dimension, high precision, good stability, multiparameter and multi loading-unloading path. Experiments of coal under different gas pressures, lateral pressure ratio and unloading path are carried out with the system, analysis of total stress-strain curve, acoustic emission and charge induction signal. The results show that the strength of peak and residual, ductility of coal are changed by methane;the anisotropy characteristics gradually weakened with the decrease of lateral pressure ratio;strain developed in the direction of low stress;the lateral pressure ratio and the loading/unloading path are important stress environmental factors influencing mechanical behavior of coal rock. The system provides a reliable experimental basis for the follow-up study of fluid-solid coupling mechanical behavior of coal rock containing methane.