Based on the hydraulic crack propagation criterion in concrete,an inverse analysis model for the hydraulic fracturing process of three-point bending concrete beams was established.Then a calculation method for the hydraulic crack propagation resistance of concrete was obtained.Hydraulic fracturing tests of 15 concrete beams with initial hydraulic pressures ranging from 0 MPa to 0.5 MPa in the crack were conducted.The hydraulic crack propagation processes of all beams were inversely ana lyzed and the crack propagation resistance were calculated.Results showed that,the proposed calculation model has a good performance in inverting the hydraulic fracture propagation process of concrete beam,and the error between the calculated P-CMOD curves and the measured P-CMOD curve was less than 10%.The variation law of the resistance of hydraulic crack propagation in concrete under different water pressures was basically similar.The crack propagation resistance decreased significantly with the initial water pressure increased from 0 MPa to 0.3 MPa,while the change in crack propagation resistance was small with the water pressure increased from 0.3 MPa to 0.5 MPa.This indicates that water pressure reduces the crack resistance of the concrete under hydraulic fracturing,but the effect is limited within low water pressure.
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