Study on construction method of three-dimensional numerical model of coal with fracture structure

There are a large number of fracture structures with different forms in coal and rock mass, which indirectly affect and determine the mechanical properties of coal and rock mass. It is necessary to accurately grasp fracture structure and reconstruct 3D numerical model to stucly mechanical properties of coal and rock mass. The threshold segmentation of coal sample slices is carried out by using the combined methods of CT scanning, rock mechanics experiment, image processing technology and RFPA3D-CT to extract the three-dimensional fracture structure of coal sample, establish a three-dimensional numerical model that is basically consistent with the internal fracture structure and mechanical properties of the studied coal sample, and embed RFPA3D-CT for uniaxial loading numerical simulation analysis. The results show that: the three-dimensional numerical model of coal sample can reflect the complex internal micro-fracture structure well. The uniaxial compression test and numerical simulation test have strong similarities in failure morphology and stress-strain curves, and the average error of uniaxial compressive strength and elastic modulus is only 1.56% and 2.22% respectively. Finally, the correctness of the construction method of three-dimensional numerical model of coal sample is verified.