微观裂隙变形及其对宏观波速压力依赖性的影响研究OA

During the crack closure process,traditional theories often assume an unchanged major axis,but a narrowing minor axis.However,due to stress interactions,a uniformly distributed stress leads to simultaneous narrowing of the major and minor axes during fracture closure.To systematically study this deformation process,an elliptical cracked model is first constructed,and the numerical model's accuracy is verified using the closing law.Based on this,a series of random medium models are built,and the practical medium theory is introduced to explore the influence of fracture deformation on the effective wave velocity.The results show that the cracked closure will significantly affect P-wave velocity but have almost a negligible effect on S-wave velocity.For the models with various groups of cracks,the stress-dependency of the P-and S-waves failed to exhibit the staged characteristics,and the pressure dependence of the wave velocity results in the values of the model closure pressure and the slope of the linear segment of the velocity.This study can lay a theoretical foundation for future inversion of fracture distribution and geometric statistical parameters from model pressure-dependence data.