Effects of bedding characteristics on crack propagation of coal under mode Ⅱ loading:Laboratory experiment and numerical simulation  

作　　者：Zhuang Sun Yixin Zhao Yirui Gao Xiaoliang Wang Hao Wang Bin Liu Yaodong Jiang 

机构地区：[1]Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources,China University of Mining and Technology(Beijing),Beijing,100083,China [2]School of Energy and Mining Engineering,China University of Mining and Technology(Beijing),Beijing,100083,China [3]State Key Laboratory of Coal Resources and Safe Mining,China University of Mining and Technology(Beijing),Beijing,100083,China [4]State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines,Anhui University of Science and Technology,Huainan,454003,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2025年第2期1037-1052,共16页岩石力学与岩土工程学报(英文)

基　　金：financially supported by the National Natural Science Foundation of China(Grant Nos.52225402,U1910206);the National Key Research and Development Project of China(Grant No.2022YFC3004602).

摘　　要：The fracture network of hydraulic crack is significantly influenced by the bedding plane in coalbed methane extraction.Under mode Ⅱ loading,crack deflection holds a key position in hydraulic cracking,especially in hydraulic shearing.This study first analyzed the crack deflection theory of layered rock.The semi-circle bending test under asymmetric loading is performed,and the four-dimensional Lattice Spring Model(4D-LSM)is established to examine how the bedding parameters affect coal crack propagation under mode Ⅱ dominant loads.The 4D-LSM results are comparable to the coal loading test results under quasi-mode Ⅱ and the analytical prediction of crack deflection theory.During mode Ⅱ loading,the coal crack propagation is greatly influenced by the angle,strength,and elastic modulus of the bedding plane,while the effects of thickness and spacing of bedding are insignificant.The crack of coal tends to propagate towards the bedding,following a decrease in bedding angle,a decrease in bedding strength,and an increase in elastic modulus.With higher bedding strength,spacing,and thickness,the peak load on the coal sample is higher.The influences of bedding strength,elastic modulus,spacing,and thickness on the peak load of coal samples and its anisotropy gradually decrease.It is proved that compared with the tangential stress ratio and traditional energy release ratio theories,the corrected energy release ratio criterion can more accurately predict the direction of crack deflection of coal,especially under mode Ⅱ loading.The results can provide assistance in the design of initiation pressure and fracturing direction in coal seam hydraulic fracturing.

关 键 词：Bedding plane COAL ModeⅡdominant loading Crack propagation 4D-lattice spring model(4D-LSM) 

分 类 号：TU45[建筑科学—岩土工程]