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任建喜, 景帅, 张琨. 冲击倾向性煤岩动静载下破坏机理及声发射特性研究[J]. 煤炭科学技术, 2021, 49(3): 57-63. DOI: 10.13199/j.cnki.cst.2021.03.006
引用本文: 任建喜, 景帅, 张琨. 冲击倾向性煤岩动静载下破坏机理及声发射特性研究[J]. 煤炭科学技术, 2021, 49(3): 57-63. DOI: 10.13199/j.cnki.cst.2021.03.006
REN Jianxi, JING Shuai, ZHANG Kun. Study on failure mechanism and acoustic emission characteristics of outburst proneness coal rock under dynamic and static loading[J]. COAL SCIENCE AND TECHNOLOGY, 2021, 49(3): 57-63. DOI: 10.13199/j.cnki.cst.2021.03.006
Citation: REN Jianxi, JING Shuai, ZHANG Kun. Study on failure mechanism and acoustic emission characteristics of outburst proneness coal rock under dynamic and static loading[J]. COAL SCIENCE AND TECHNOLOGY, 2021, 49(3): 57-63. DOI: 10.13199/j.cnki.cst.2021.03.006

冲击倾向性煤岩动静载下破坏机理及声发射特性研究

Study on failure mechanism and acoustic emission characteristics of outburst proneness coal rock under dynamic and static loading

  • 摘要: 煤矿巷道发生冲击地压破坏后果严重,具有冲击倾向性的煤岩具备发生冲击地压的潜质,在高应力状态下经动载诱发后极易发生破坏,其破坏与变形规律与常规静载不同。为了探究冲击倾向性煤岩在动静载下破坏及变形规律,以深埋煤层巷道高应力下具有冲击倾向性的煤岩作为研究对象,采用动载三轴及声发射检测设备,模拟煤岩所处高应力环境及动载条件,通过对比不同围压下的静载破坏试验,一定应力水平下动载诱发试验,不同应力阶段动载加载试验,分析其变形破坏机理及声发射能量演化规律。结果表明:与静载加载破坏相比动载导致煤岩提前进入屈服变形阶段且强度劣化明显,其破坏程度更加严重,并由剪切破坏转变为横向拉伸破坏;声发射点能有效定位煤岩破坏阶段内部裂隙发育区域及主破坏方向。煤岩达到动载破坏条件存在一个临界静载,未达到临界静载时煤岩在动载作用下裂隙发育及应变增长会逐渐稳定,超过临界静载后煤岩在动载作用下会迅速发生破坏。与静载相比动载后煤岩储存弹性能增加,破坏后释放更多能量;煤岩声发射能量事件主要发生在动载加载初期及峰后破坏阶段,动载加载后有明显凯泽效应。研究结论认为声发射能量演化规律可作为判断煤岩所处应力状态及先期动载加载应力水平的参考依据。

     

    Abstract: The damage caused by rock burst in coal mine roadways is serious,and the coal rock with burst tendency has the potential to generate failure.Under high stress,it is prone to damage after being disturbed by dynamic load,and its damage and deformation laws are different from conventional staticload.Taking the coal rock with burst tendency under high stress in deep coal seam roadway as the research object to explore the failure and deformation law of coal rock with burst tendency under dynamic and static loads.The dynamic triaxial test and acoustic emission test equipment are used to simulate the high stress environment and dynamic load conditions of coal rock.By comparing the static load failure test under different confining pressures,the dynamic load induced test under a certain stress level,the dynamic loading test atdifferent stress stages to analyze the deformation and failure mechanism and the evolution law of acoustic emission energy.The results show that the dynamic load causes the coal rock to enter the yield deformation in advance and the strength deteriorates obviously.Compared with the static load,the damage degree becomes more serious,and the shear failure transforms into the transverse tensile failure; the acoustic emission point can effectively locate the coal rock fissure development area and the main direction of destruction.There is the critical static load when the coal rock reaches the dynamic load failure condition; the fracture and strain growth of the coal rock will be gradually stabilized under the dynamic load disturbance if the critical static load is not reached,and the rapid destruction will occur after the critical static load.the storage elastic energy of coal rock increases after the dynamic load,which releases more energy than the static load at failure.The energy events of coal rock mainly occur in the initial stage of dynamic loading and the stage of peak failure under confining pressure.There is obvious kaiser effect after dynamic loading.The research conclusion is that the evolution law of acoustic emission energy has reference value for identifying the stress state of coal rock and the initial dynamic load stress level.

     

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