基于深部含水煤样失稳特征的荷载梁式主控裂隙模型的试验研究

Experimental study on a loading beam main control crack model based on the instability characteristics of deep coal samples containing water

深部巷道周边的煤体在承受高地应力基础荷载的同时,往往还受到由远及近的采掘活动扰动,使其内部的裂隙损伤在近似于高应力逐级加卸载的应力路径下不断发育,若还处于水岩作用的影响下,承载性能将进一步劣化。通过对某矿深部煤样进行吸水特性描述、波速信息对比、力学试验分析及声发射监测,总结了该矿深部含水煤样具有以下特征:吸水迅速、极易饱和、饱水后整体结构完整性增强,且主要以张开型主控裂隙的张拉破坏造成试件整体失稳。基于上述特征,结合吸水率、裂隙参数、系统尺寸等因素,优化建立了荷载梁式主控裂隙模型,阐述了深部含水煤样产生上述失稳特征的机制,并进行了敏感性分析、强度验证,验算结果较为贴合试验数据,可为深部高应力扰动富水巷道中的裂隙煤岩体进行类似的试验研究、理论建模及采掘设计提供一定的参考。

The coal mass around deep roadways are often disturbed by mining activities from far to near,while bearing high ground stress loads.As a result,the internal crack damage continues to develop in a stress path similar to the gradual loading and unloading of high stress.If they are still under the influence of water and rock interaction,their bearing capacity will further deteriorate.The water absorption characteristics,wave velocity comparisons,mechanical experimental analyses,and acoustic emission monitoring of deep coal samples from a mine indicate that the deep coal samples containing water exhibit characteristics including rapid water absorption,easy saturation,and overall integrity enhancement after water saturation,and they are mainly characterized by the tensile failure of the open main control crack,which causes the overall failure of the specimen.According to the above characteristics,a loading beam main control crack model is optimized and established herein by combining some factors such as the water content,crack parameters,and system size.The mechanism of the instability characteristics mentioned above deep water-bearing coal samples was elaborated,and the sensitivity analysis and strength verification were conducted.The obtained results were in good agreement with the experimental data,which can serve as a reference for similar experimental research,theoretical modeling,and mining design of fractured coal-rock mass located in deep high stress disturbed water-rich roadways.