Experimental Study On CT Detection Of Micro Cracks In Coal Underuniaxial Compression

The variation of mining stress has a direct influence on the development of coal and rock fractures.It is of great significance to study the evolution law of coal and rock fractures.In this paper,the development status and research at home and abroad on damage of fractured coal rock fracture evolution,combined with experimental research,theoretical analysis,numerical simulation,coal rock damage fracture is studied by MATLAB software technology.Specific research work and research results include the following aspects:At first the theory of damage mechanics is studied,and the damage theory model is fitted by subsequent tests and data processing.The results show that the model agrees well with the experimental curve and proves the feasibility and rationality of the model.Next through the compression test of coal samples,the process of uniaxial compression is studied.Combined with the CT scanning image,the CT images corresponding to four stages in the uniaxial compression process are extracted.The results show that micro crack to fracture development is the main reason of tip stress;under uniaxial loading conditions,coal rock fracture development is the main direction of the axial stress along the direction of crack;the development of fissures is mainly the destruction of microcracks first,and the stress concentration of microcracks promotes the development of large fractures.Finally combined with MATLAB software,the fracture evolution law of coal and rock mass is studied.Using the software program to complete the CT image information extraction.The deformation and failure of coal and rock is a gradual process of development: from the deformation,damage and evolution of micro cracks and macro cracks,and then extended to the whole process through destruction through the cracks.During the loading process,the secondary cracks will not develop at the stress concentration points.With the formation of the transfixion fracture and the axial pressure reaching the elastic yield limit of the coal sample,the development of the secondary fracture has been penetrated,and a large fissure has been formed.