针对煤矿沉积岩系地应力测试需要,通过单轴压缩声发射实验,分析顶板含层理沉积岩系岩石试件的破坏特征、声发射特征,研究Kaiser效应点的综合判断方法及基于声发射Kaiser效应的地应力计算方法。研究表明:(1)单轴荷载作用下,无层理岩石试件破坏过程为:加载→完全破坏,表现出脆性破坏特征;含层理构造的岩石试件的破坏过程为:加载→局部滑移剪切破坏→加载→剪切带失稳、岩石试件破坏。(2)无层理岩石试件的AE总计数随时间的增长趋势表现为"缓慢增长→急剧飙升"型,而含层理岩石则呈现出"台阶状"上升趋势,分析认为产生这种不同规律的根源在于岩石内部损伤破坏过程的差异性。(3)通过研究AE特征提出Kaiser效应点综合判断方法,并完善Kaiser效应法地应力计算方法,最终得到测点地应力为:1σ=25.06 MPa,2σ=13.75 MPa,3σ=8.07MPa,验证表明:计算结果在大小及方向上均具有一定的可信度。故提出的Kaiser效应点判断方法和地应力计算方法可用于Kaiser效应法地应力测试,该实验研究方法和结果可为工程实践或类似研究提供借鉴和参考。
To meet the need of in-situ stress test in coal mine,acoustic emission experiment under uniaxial compression was carried out to study the failure and acoustic emission characteristics of rock samples from the roof of bedding sedimentary rock series. The comprehensive estimation of Kaiser effecting points and the calculation for in-situ stress based on Kaiser effect were studied. The results showed that,under the uniaxial compression loading,the rock sample without bedding exhibited the characteristics of brittle failure. While bedding rock sample experienced a process of local slip,instability of shear zone and rock sample failure. The total AE counts of rock sample without bedding had the tendency of slow increase to rapid increase,while the bedding rock sample had a step increase. The reason of such difference is due to the difference of the inner damage of rock. A comprehensive judgment method for Kaiser effecting points was derived based on AE characteristics,and an in-situ stress calculating method based on Kaiser effect was improved. Moreover,the final results of in-situ stress were that.1σ = 25.06 MPa,2σ = 13.75 MPa and 3σ = 8.07 MPa.