工程地质学报2023，Vol.31Issue(6)：1854-1862,9.DOI:10.13544/j.cnki.jeg.2021-0585
静载下含预制裂隙煤岩力学特性及破坏特征试验研究
EXPERIMENTAL STUDY ON MECHANICAL PROPERTIES AND FAILURE CHARACTERISTICS OF COAL ROCK WITH PREFABRICATED FRAC-TURE UNDER STATIC LOADING
摘要
Abstract
Coal rock with prefabricated fractures has different mechanical properties and failure characteristics from intact coal rock under external loading.The three-dimensional macro fracture prefabrications of intact coal rock sam-ples with different dip angles(30°,45°,and 60°)were carried out by diamond wire cutting method.Through uniax-ial and triaxial compression tests and combined with acoustic emission monitoring techniques,the strength,deform-ation,failure mode,fracture propagation law and acoustic emission characteristics of the fractured coal rocks under different loading conditions were studied.The law of instability and failure of fractured coal rock with impact tend-ency were explored.The results show the follows.The strength and elastic modulus of intact coal rock have a good linear relationship with confining pressure.The strength increases by 400％as the confining pressure increases from 0 MPa to 16 MPa.The failure mode is shear failure and the shear angle increases.The existence of prefabricated fractures reduces the strength of coal rock.The strength of 30°,45°and 60°fractured coal rocks decreases by 13％,24％and 37％,respectively.When the failure occurs,the new wing fractures expand from the fracture tip along the direction of maximum principal stress and join the prefabricated fracture,resulting in instability failure of the coal rock.When the confining pressure of fractured coal rock increases to a certain level,the"reverse confining pres-sure effect"occurs,that is,the greater confining pressure is,the more obvious strength deterioration is.When the confining pressure reaches 8 MPa,the strength of three kinds of fractured coal rocks decreases by 200％.The a-coustic emission intensity of the intact coal rock reaches the extreme value in the failure stage.The acoustic emis-sion signal surge point of fractured coal rock is generated in each stage due to the fracture expansion and develop-ment,according to which the failure degree and stress state of fractured coal rock can be judged.关键词
裂隙煤岩/冲击失稳/力学特性/破坏特征/试验研究Key words
Fractured coal rock/Shock instability/Mechanical properties/Failure characteristics/Experimental study分类
天文与地球科学引用本文复制引用
任建喜,谷禹,贾龚杰,王晓琳,岳东,霍小泉..静载下含预制裂隙煤岩力学特性及破坏特征试验研究[J].工程地质学报,2023,31(6):1854-1862,9.基金项目
国家自然科学基金项目(资助号:11872299,12072259),陕西省自然科学基金煤炭联合基金(资助号:2019JLP-01).This research is supported by the National Natural Science Foundation of China(Grant Nos.11872299,12072259)and Coal Joint Fund of Natural Science Foundation of Shaanxi Province(Grant No.2019JLP-01). （资助号:11872299,12072259）
