煤岩破坏过程的细观力学损伤演化机制

为了有效监测煤岩巷道围岩的损伤稳定程度,以漳村矿煤岩为例开展了煤岩损伤破坏特性的研究,首先对该矿煤岩进行单轴压缩试验测得其力学参数,然后通过颗粒流软件获得其细观力学参数进行了不同围压下煤岩试验。分析了煤岩破坏过程的声发射和应变能变化规律,并从煤岩损伤萌生、成核、扩展和贯通的过程研究了损伤演化机制,获得以下结论:最大声发射强度与峰值应力并不同时出现,具有一定滞后性,低围压范围滞后效应随围压变化敏感,高围压范围围压对其影响减弱;随着围压增加在最大声发射前会出现明显的平静期,并指出平静期的出现是由煤岩内部严重损伤区的产生和损伤愈合吸收应变能所致;将煤岩损伤破坏过程分为微损伤弥散分布、损伤局部集中发展成核、裂纹稳步扩展形成局部裂隙、局部裂隙贯通煤岩失稳4个阶段,指出围压对各个阶段的影响异同。

Damage evolution mechanism in the failure process of coal rock based on mesomechanics

In order to effectively monitor the damage and stability extent of coal rock roadway，conduct the studies of coalrock damage and failure characteristics in Zhangcun Coal Mine.Firstly，the mechanics parameters of coal rock measured through the uniaxial compression experiment in Zhangcun Coal Mine，then obtained the mesomechanics parameters of coal rock and experiments carried out under different confining pressures by particle flow code.Analyzing the acoustic emission and strain energy characteristics in the failure process of coal rock，and consequently revealed the coal rock failure mechanism through the generation，propagation and coalescence process of cracks.Some main research results are as follows：the maximum intensity of acoustic emission lags behind the peak stress，the lag is sensitive with confining pressure in lower confining pressure range，the effect is attenuated in higher range.Arise the significant quiet period of acoustic emission before the maximum intensity of acoustic emission with confining pressure increasing，and point out the quiet period caused by the strain energy absorption in the process of the generation of serious damage zone and damage healing.Coal rock failure process is divided into four stages：damage random dispersion，damage coalescence in local scope，fissure steady developing into local crack，crack extension bring about coal rock failure.Analyzing the effect of confining pressure on the four stages.