A novel collaborative study of abnormal roof water inrush in coal seam mining based on strata separation and wing crack initiation

•In this work, the process of water inrush due to roof bed separation was studied by similar simulation experiment and analytical wing crack initiation condition.•New maximum tangential tensile stress (MTTS) criterion, maximum shear stress magnitude (MSSM) criterion, and minimum J2 criterion by considering T-stress at the crack tip were proposed.•The experiment could reveal the evolution law of bed separation space, the process of water accumulation in the bed separation space, and the breaking characteristics of separation water inrush.•Our analytical solution of wing crack initiation angle is approximately consistent with the experimental observation after water injection.•The consistency between the similar experiment and the field result was illustrated.