Study On Quantification And Characterization Of Three-dimensional Shape For Rock Cracks

In view of the difficulty in observing and quantifying the damage area of macro large-scale rock mass,a method that is based on the Mohr-Coulomb failure criterion is proposed in this paper to quantify the macro-meso damage area of rock mass numerical model.The numerical simulation method is used to simulate the failure of a rock slope.According to the mapping principle of bitmap and the principle of Matlab image processing,the damage area of the model can be identified and extracted.And 3D reconstruction of the damaged area can be realized finally.The research results are as follows:(1)Homogeneous and non-homogeneous slope models are established.The strength parameters of non-homogeneous model are randomly assigned according to the Weibull distribution.Based on the analysis of the statistical data,it can be seen that the larger the shape parameter m is,the more uniform distribution of the material parameters in the model.The distribution of the damage area of the non-homogeneous model is discrete,and is consistent with the actual situation.(2)Based on the Mohr-Coulomb failure criterion,a new method,called safety factor method,for the quantification of macro-meso cracks in rock mass model is proposed by means of theoretical derivation.When the safety factor is greater than 1,the model element is at the safe state;when the safety factor is equal to 1,the model element is at the critical state;when the safety factor is less than 1,the model element is at the damage state.(3)According to the mapping principle of bitmap and the principle of Matlab image processing,a method of identifying and extracting the color threshold of the image is proposed and then used to recognize and extract the damage characteristics of the model.This method provides a theoretical basis for 3D reconstruction of damage characteristics of the model.(4)Based on Matlab's powerful data processing function,the 3D reconstruction of damaged area of rock mass model is realized by identifying and extracting successively the color characteristics of the damage areas in a series of safety factor contour maps as well as by superposing these color characteristics in order of height.The 3D reconstruction of rock mass model's damage characteristics can not only offer the readers a more intuitive visual experience,but also provide an important guiding role for the reinforcement design of the macro engineering.The 3D reconstruction technology can not only serve the projects,but also can be used in other industries.It has a bright future.