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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. (c) 2025 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).

来源平台：JOURNAL OF ROCK MECHANICS AND GEOTECHNICAL ENGINEERING