Simulation on mesoscopic deformation and failure mechanism of dissolved rock mass using digital image processing technology

The dissolved rock mass is widely distributed in southwest China,of which deterioration of the mechanical properties can cause geological hazard in special conditions. Due to the particularity of its material composition and structural characteristics, it is difficult to collect samples of dissolved rock mass and conduct laboratory tests. To solve this problem, taking a project slope in Guizhou Province as an example, this work extracts dissolution information from this rock mass using the digital image technology. Firstly, the morphological characteristic parameters of the dissolved rock mass are obtained by digital image processing technology, and then the discrete element model of the dissolved rock mass is constructed on the basis of parameter calibration,finally, the deformation and failure characteristics and fracture evolution law of the dissolved rock mass are analyzed by the uniaxial compression numerical test. The results show that the stress-strain curve of dissolved rock can be divided into three stages,elastic deformation stage,stable deformation stage and failure stage. The stress-strain relationship of dissolved rock mass is the macroscopic manifestation of the change law of the contact force inside the specimen. The failure of dissolved rock mass is progressive. Because of the existence of dissolved holes, the contact force chain of the dissolved rock mass shows anisotropic characteristics. As the load increases continuously, the external load is mainly borne by the rock skeleton, which shows that the range of contact force chain increases continuously. With the increase of strain, the failure began to occur around the dissolved hole of the specimen, and then the failure area continued to expand, and the contact force chain scope continued to decrease,eventually, the failure occurred in the specimen and the force chain disappeared. The model of dissolved rock mass based on digital image processing technology can well represent the characteristics of dissolved rock mass. Moreover,the meso-scale deformation and failure mechanism of dissolved rock mass is of great guidance and practical significance to the study of geological disasters such as karst collapse and rock avalanche.