Experimental and CDEM Analysis on Crack Propagation Mechanism of Rock-Like Material Containing Flaws Under Uniaxial and Biaxial Compression

Abstract: Uniaxial and biaxial tests are performed to investigate the evolution mechanism of crack propagation and coalescence through developing newly cement mortar materials with horizontal and inclined pre-existing flaws. Additionally, a new numerical method-CDEM (Continuous discrete element method) is employed to analyze the evolution laws of stress field of crack tips under hydraulic coupling. The results reveal that the maximum principal stress of the wing crack tip gradually decreases with increase of internal water pressure, and the initiation stress, initiation angle and peak strength show decreasing trend. The results of crack propagation and coalescence obtained by numerical simulation is consistent with laboratory results. With the water pressure increases, prior to the occurrence of wing cracks, the coplanar cracks firstly initiate around inclined flaws. Under the coupling action of uniaxial compression and internal water pressure, the lateral pressure would limit the initiation of the wing cracks, while the increasing water pressure weakens the inhibition of lateral pressure on wing cracks.