深部采动应力条件下砂岩破裂的声发射和能量演化规律研究  

Acoustic emission and energy evolution of sandstone failure subjected to deep mining stress

作　　者：刘超 尹思禹 张锦 张东明[3] 王亮[4] 赵宏刚[3] LIU Chao;YIN Siyu;ZHANG Jin;ZHANG Dongming;WANG Liang;ZHAO Honggang(State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;School of Mechanics and Civil Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing 400030,China;Key Laboratory of Gas and Fire Control for Coal Mines,Ministry of Education,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;Dongtan Coal Mine,Yanzhou Coal Mining Co Ltd,Jining,Shandong 273500,China)

机构地区：[1]中国矿业大学深部岩土力学与地下工程国家重点实验室,江苏徐州221116 [2]中国矿业大学力学与土木工程学院,江苏徐州221116 [3]重庆大学煤矿灾害动力学与控制国家重点实验室,重庆400030 [4]中国矿业大学煤矿瓦斯与火灾防治教育部重点实验室,江苏徐州221116 [5]兖州煤业股份有限公司东滩煤矿,山东济宁273500

出　　处：《采矿与安全工程学报》2022年第3期470-479,共10页Journal of Mining & Safety Engineering

基　　金：国家自然科学基金项目(51874053,51974300,51579239);中央高校基本科研业务费专项项目(2021QN1027)。

摘　　要：深部采动应力可影响岩石材料变形损伤过程的声发射特征和能量演化规律,以砂岩为研究对象,进行了不同静水应力(采深)和Lode角(采动应力路径)(-30°~30°)条件下的真三轴加卸载试验。结果表明:静水应力和Lode角对岩石变形及强度都有较大的影响。静水应力相同时,Lode角的增加会促进微裂隙的扩展和贯通,从而降低砂岩试样的承载能力,使其破坏更加迅速且剧烈;Lode角相同时,3个方向的应变均随静水应力的升高而增大,且静水应力升高可以增加砂岩试样的延性,使其在较大变形时才发生失稳破坏。声发射参数特征与岩石各阶段变形保持良好的对应关系,不同阶段所对应的AF值(平均频率)和RA值(上升时间与幅值的比值)存在较大差异,表明各阶段的损伤类型不同,且越接近峰值破坏点,剪切作用越明显。此外,岩石在峰值破坏点前的能量转化特征较好地体现了损伤演化规律,能耗比m(耗散能U与总能量U之比)大体呈现先减小后稳定再增加的趋势,且应变硬化阶段的能耗比增量基本相同,说明加载时间越长,岩石的峰值强度越大,吸收的总能量也越多,破坏时需要的耗散能也会随之增加。Deep mining stress has an important impact on acoustic emission characteristics and energy evolution law of rock during its deformation and damage. With sandstone as research object, true triaxial loading-unloading experiments were performed under different hydrostatic stress(mining depth) and Lode angles(mining stress path)(-30°-30°). The results have shown that hydrostatic stress and Lode angle have great influence on the deformation and strength of sandstone. With the same hydro-static stress, the increase of Lode angle promotes expansion and penetration of micro-cracks and reduces bearing capacity of sandstone, making the destruction more rapidly and intensely. With the same Lode angle, the principal strain in three directionsincreases with hydro-static stress increasing, and the ductility of sandstone is enhanced. Furthermore, specimens encounter unstable failure at large deformation. The acoustic emission parameters are in good correspondence with each loading-unloading stage of sandstone. AF(average-frequency) and RA(the ratio of rise time and amplitude) in different stages have great differences, indicating different damage types in each stage. Meanwhile, the shearing effect is more obvious when the sandstone is closer to the peak failure point. In addition, the damage evolution is well displayed by energy conversion characteristics of rock. The energy consumption ratio m(the ratio of dissipated energy Uand total energy U) tends to decrease first, then keeps constant, and finally increases. The increment of m in the strain-hardening stage is almost same, and rock strength increases with loading time. Moreover, as the static loading time increases, the more energy absorbed, the more dissipated energy is consumed.

关 键 词：静水应力 Lode角 声发射 能量 损伤 

分 类 号：TD315[矿业工程—矿井建设]