Buertai Coal Mine, China Energy Shendong Coal Group Co., Ltd.
China Coal Technology and Engineering Group Coal Mining Research Institute

围压作用下煤体冲击倾向性研究对于探明地下深部矿井中煤体冲击地压形成机理起着关键作用。为了探究不同围压作用对煤体冲击倾向性的影响，对煤体进行了多级围压下不同应力下限循环加卸载。结果表明：在3、6、9 MPa围压环境下变应力下限循环加卸载作用后煤试件抗压强度分别增加了3.1%、4.7%、6.2%，最后一级循环加卸载过程中轴向应变分别增加了0.61%、0.42%、0.28%，体积应变分别增长了0.32%、0.24%、0.17%，表明煤体受到的围压越大对煤体变形约束越强；随着围压的提高，声发射事件累积数量逐渐降低，峰后声发射累积数量不断降低，累积能量同样逐步降低，表明随着围压的升高，煤试件变得更加致密，破坏形式逐渐由脆性破坏过渡到韧性破坏；经过3、6、9 MPa围压作用，输入能$U_{{rm{in}}}^{rm{n}} $与弹性应变能$U_{rm{e}}^{rm{n}} $不断升高，较之常压条件下煤试件剩余弹性能指数CEF分别提高了21.76%、42.92%、71.69%，说明围压对煤体冲击倾向性具有增强作用，且剩余弹性能指数CEF与围压σ3具有线性函数关系。

The study of coal bump-prone property under confining pressure plays a key role in exploring the formation mechanism of coal burst in deep underground mines. In order to explore the influence of different confining pressures on bump-prone property of coal, this paper carried out cyclic loading and unloading of coal with different stress lower limits under multistage confining pressures. The test results show that: under the confining pressure environment of 3 MPa, 6 MPa and 9 MPa, the compressive strength of coal specimens increased by 3.1%, 4.7% and 6.2% respectively after cyclic loading and unloading, and the axial strain increased by 0.61%, 0.42% and 0.28% respectively in the last stage of cyclic loading and unloading. The volumetric strain increases by 0.32%, 0.24% and 0.17%, respectively, indicating that the larger the confining pressure is, the stronger the deformation constraint is. With the increase of confining pressure, the cumulative number of AE events gradually decreases, the cumulative number of AE after peak continuously decreases, and the cumulative energy also gradually decreases, indicating that with the increase of confining pressure, the coal specimen becomes more compact, and the failure mode gradually transitions from brittle failure to ductile failure. In addition, after the confining pressures of 3 MPa, 6 MPa and 9 MPa, the input energy $U_{{rm{in}}}^{rm{n}} $ and elastic strain energy $U_{rm{e}}^{rm{n}} $ increase continuously. Compared with the normal pressure condition, the residual elastic energy index (CEF) of coal specimens is increased by 21.76%, 42.92% and 71.69%, respectively, indicating that confining pressure has an enhanced effect on the bursting tendency of coal, and the residual elastic energy index (CEF) has a linear function relationship with confining pressure σ3.

山西省科学技术厅青年科技研究基金资助项目（201901D211004）；山西省应用基础研究计划资助项目（20210302124440）

张传玖，杜涛涛，任建慧，等. 多级围压变应力下限循环加卸载煤体冲击倾向性特征研究[J]. 煤矿安全，2023，54（10）：107−116.

ZHANG Chuanjiu, DU Taotao, REN Jianhui, et al. Study on bump-prone property of coal under multi-stage confining pressure variable stress lower limit cyclic loading and unloading[J]. Safety in Coal Mines, 2023, 54（10）: 107−116.