煤体恒定加载蠕变损伤实验的研究

为了得到恒定荷载作用下煤体蠕变损伤破坏规律,采用速率为0.2 kN/s的荷载控制加载方式,加载至15 kN后保持不变.监测和分析恒定荷载下煤体的轴向变形、径向变形和应变随时间的变化情况以及能量、幅值、撞击和声发射事件等声发射信息随时间的变化.结果表明：声发射信息随着煤体损伤状况的变化表现出不同的特征;声发射事件沿着轴力方向增加,主要集中在煤体内部中间部位;声发射事件产生的位置、速率,可以直观反映煤体表面裂隙在煤体内部发育状况和蠕变过程中裂隙扩展方向及速率,对分析煤体蠕变损伤状况和预测煤体蠕变破坏位置具有重要意义.

Experimental study on creep damage of coal body subjected to constant load

This paper is an effort to investigate the law underlying coal creep damage and fracture due to the occurrence of uniaxial stable load.This specific investigation consists of controlling the load mode by varying the loading rate from 0.2 kN/s,to 15 kN set to remain unchanged ; and monitoring and analyzing the changes in the axial deformation,the radial deformation and strain conditions over time,and the changes of the acoustic energy,the amplitude,the impact and the acoustic emission events over time.The results reveal that：acoustic emission exhibit different characteristics activity following the changes of the load over time; AE events tend to increase along the direction of the axial force and are concentrated mainly in the middle part inside the coal body; the location and rate associated with the generation of the AE events are capable of an intuitive reflection of the coal surface cracks developing inside the coal body,as well as the direction and the rate of the crack propagation during creep and thus assume a greater importance to the analysis of the creep damage and the prediction of the creep rupture location.