为研究裂隙倾角对预制平行双裂隙煤体动态抗拉性能及破坏行为影响规律,采用分离式霍普金森压杆试验系统对预制平行双裂隙煤样开展动态劈裂试验,并同步对煤样动态破坏过程进行记录,分析了不同裂隙倾角(0°、30°、45°、60°、75°和90°)裂隙煤样动态力学特性和裂纹演化规律,并对裂纹扩展分形特征及能量演化规律进行了讨论。结果表明:不同裂隙倾角双裂隙煤样峰值载荷分布范围为1.17~2.03 kN,整体随裂隙倾角的增大呈先增大后减小再增大趋势;不同裂隙倾角煤样均以拉伸破坏为主,且裂纹沿加载方向发育;煤样中部(两加载点连线附近区域)率先起裂,随后在预制双裂隙端部以及试样与压杆接触位置萌生反翼型裂纹和剪切裂纹,裂纹进一步扩展贯通形成破裂面;裂纹扩展分形维数分布范围为1.76～1.83,且在加载过程中呈增加趋势;裂隙倾角为75°时破坏时刻分形维数最大,裂隙倾角为60°时分形维数最小;不同裂隙倾角煤样吸收能演化规律基本一致,整体呈“S”型增长,可划分为初始稳定阶段、快速增长阶段和缓慢增长阶段。
To investigate the influence of fissure angle on the dynamic tensile properties and failure behavior of coal with prefabricated parallel double fissures, dynamic splitting tests were conducted on coal samples containing prefabricated parallel double fissures using a split Hopkinson pressure bar (SHPB) test system. The dynamic failure process of coal was recorded simultaneously. The dynamic mechanical properties and crack evolution patterns of coal with different fissure angles (0°, 30°, 45°, 60°, 75°, and 90°) were analyzed, and the crack propagation fractal characteristics and energy evolution were discussed. The results show that: The peak load ranges from 1.17 to 2.03 kN, exhibiting an overall trend of first increasing, then decreasing, and subsequently increasing again with increasing fissure angles. All samples predominantly fail in tensile mode, with cracks developing along the loading direction. Initial cracks occur at the sample center (the area near the line connecting the two loading points), followed by anti-wing cracks at the prefabricated fissure and shear cracks at contact interfaces between samples and pressure bars. These cracks further propagate and coalesce to form fracture surfaces. The fractal dimension of crack propagation ranges from 1.76 to 1.83, showing an increasing trend during loading. The maximum fractal dimension at failure occurs at 75° fissure angle, while the minimum value appears at 60°. The evolution of absorbed energy followed “S”-shaped growth patterns, which can be divided into an initial stable phase, a rapid growth phase, and a slow growth phase.
[1] 袁亮,王恩元,马衍坤,等.我国煤岩动力灾害研究进展及面临的科技难题[J].煤炭学报,2023,48(5):1825-1845.
[2] 何满潮,武毅艺,高玉兵,等.深部采矿岩石力学进展[J].煤炭学报,2024,49(1):75-99.
[3] Li X,Gong F,Tao M,et al.Failure mechanism and coupled static-dynamic loading theory in deep hard rock mining:A review[J].Journal of Rock Mechanics and Geotechnical Engineering,2017,9(4):767-782.
[4] Yang S Q.Crack coalescence behavior of brittle sandstone samples containing two coplanar fissures in the process of deformation failure[J].Engineering Fracture Mechanics,2011,78(17):3059-3081.
[5] Yang S Q,Yang D S,Jing H W,et al.An experimental study of the fracture coalescence behaviour of brittle sandstone specimens containing three fissures[J].Rock Mechanics and Rock Engineering,2012,45(4):563-582.
[6] 赵洪宝,胡桂林,李伟,等.预制裂隙岩石裂纹扩展规律的研究进展与思考[J].地下空间与工程学报,2016,12(增2):899-906.
[7] Yang S Q,Huang Y H,Jing H W,et al.Discrete element modeling on fracture coalescence behavior of red sandstone containing two unparallel fissures under uniaxial compression[J].Engineering Geology,2014,178:28-48.
[8] 杨圣奇,黄彦华,刘相如.断续双裂隙岩石抗拉强度与裂纹扩展颗粒流分析[J].中国矿业大学学报,2014,43(2):220-226.
[9] Zhang X P,Liu Q S,Wu S C,et al.Crack coalescence between two non-parallel flaws in rock-like material under uniaxial compression[J].Engineering Geology,2015,199:74-90.
[10] Zhang J Z,Zhou X P,Zhu J Y,et al.Quasi-static fracturing in double-flawed specimens under uniaxial loading:the role of strain rate[J].International Journal of Fracture,2018,211(1-2):75-102.
[11] Huang Y H,Yang S Q,Tian W L.Crack coalescence behavior of sandstone specimen containing two pre-existing flaws under different confining pressures[J].Theoretical and Applied Fracture Mechanics,2019,99:118-130.
[12] 李斌,杨圣奇,田文岭.充填与非充填双裂隙巴西圆盘试样力学特性试验研究[J].应用基础与工程科学学报,2019,27(3):628-645.
[13] Bai Y,Shan R L,Ju Y,et al.Experimental study on the strength,deformation and crack evolution behaviour of red sandstone samples containing two ice-filled fissures under triaxial compression[J].Cold Regions Science and Technology,2020,174:103061.
[14] Li B X,Yu S,Zhu W S,et al.The crack coalescence mode and physical field evolutionary characteristics of a brittle material containing two 3-D parallel embedded flaws[J].Theoretical and Applied Fracture Mechanics,2020,110:102836.
[15] Zhao Y S,Gao Y T,Wu S C.Influence of different concealment conditions of parallel double flaws on mechanical properties and failure characteristics of brittle rock under uniaxial compression[J].Theoretical and Applied Fracture Mechanics,2020,109:102751.
[16] 王建明,王延廷,陈忠辉,等.卸荷条件下不等长共线双裂隙相互作用规律分析[J].煤炭学报,2020,45(11):3759-3771.
[17] 武旭,王帆,席迅,等.正交型交叉裂隙岩石强度特征与破裂机理试验研究[J].煤炭学报,2020,45(7):2681-2690.
[18] Zhou X P,Peng S L,Zhang J Z,et al.Failure characteristics of coarse and fine sandstone containing two parallel fissures subjected to true triaxial stresses[J].Theoretical and Applied Fracture Mechanics,2021,112:102932.
[19] Feng P,Dai F,Shuai K W,et al.Dynamic mechanical behaviors of pre-fractured sandstone with noncoplanar and unparallel flaws[J].Mechanics of Materials,2022,166:104219.
[20] 李祥,戴世鑫,朱伟,等.含交叉裂隙试块力学破坏及裂纹扩展研究[J].地下空间与工程学报,2023,19(2):410-419.
[21] 司余洁,肖桃李,袁浩,等.含共面双裂隙复合岩三轴力学行为及能量演化规律[J].煤炭科学技术,2024,52(12):71-83.
[22] 陈结,孟历德仁,崔义,等.基于声光联合试验的预制双裂隙砂岩损伤演化特征研究[J].岩石力学与工程学报,2025,44(1):30-42.
[23] 崔义,蒲源源,陈紫阳,等.含预制双裂隙砂岩亚失稳阶段力学特性及裂纹演化规律试验研究[J].矿业科学学报,2025,10(2):194-202.
[24] 杨科,魏祯,窦礼同,等.含水煤样动态拉伸能量演化与破坏特征试验研究[J].煤炭学报,2021,46(2):398-411.
[25] Zhang T,Liu B,Wei Z,et al.Dynamic mechanical responses and crack evolution of burst-prone coal with a single prefabricated fissure[J].Theoretical and Applied Fracture Mechanics,2022,121:103494.
[26] 金解放,徐虹,余雄,等.动荷载和含水率对红砂岩破坏及能耗特性的影响[J].岩土力学,2022,43(12):3231-3240.
