原生裂纹对岩石疲劳损伤演化的影响研究OA

To elucidate the influence of pre-existing cracks on the damage evolution of rocks under combined pre-static and cyclic disturbance loads,the geometric parameters of pre-existing cracks in granite and marble were obtained through scanning electron microscope(SEM)observations.Numerical models incorporating the actual crack distribution were constructed based on the discrete fracture network(DFN)method.The influence of pre-existing cracks on rock fatigue damage was systematically analyzed,and the evolution mechanism of micro-cracks was revealed.The results indicate that under combined pre-static and cyclic loads,pre-existing cracks significantly reduce the tensile strength and maximum axial deformation of rocks.When the influence of pre-existing cracks is considered,the total number of tensile and shear cracks increases significantly.For granite,the total number of cracks increases by approximately 30％,while for marble,the increment is about 25％.Furthermore,under combined loads,the Brazilian splitting failure of granite is primarily caused by transgranular cracks,and the presence of pre-existing cracks increases the proportion of intergranular cracks.