SIMULATION OF MECHANICAL PROPERTIES AND GEOMETRIC FEATURE FACTOR SENSITIVITY OF INTERBEDDED ROCK MASS IN URUMQI SUBWAY TUNNEL

This paper studies the mechanical properties and failure mechanism of the soft and hard interbedded rock mass in the subway tunnel. It is based on the acquisition of physical and mechanical parameters of Urumqi mudstone and sandstone. It uses the microscopic parameter to calibrate the physical and mechanical parameters of the interbedded rock mass. It uses the particle flow numerical simulation uniaxial compression test to analyze the interbedded rock mass layer thickness, the layer thickness ratio, and the inclination angle of the interbedded rock mass. The analysis results show that as the layer thickness of the interbedded rock mass increases, its uniaxial compressive strength decreases, the number of cracks also decreases, and the crack development speed increases. As the layer thickness ratio of the interbedded rock mass increases, its uniaxial compressive strength is continuously decreasing. When the layer thickness ratio is greater than 1, the uniaxial compressive strength is relatively stable, and the crack development trend is faster when the layer thickness ratio is less than 0.6. The crack development trend is slower when the layer thickness ratio is greater than 0.6. The increase of the inclination of the interbedded rock mass makes the uniaxial compressive strength show a U-shaped change trend. The uniaxial compressive strength is the lowest at the inclination 40°, the number of cracks is the largest at the inclination 90°, and the development trend is slowest. According to the orthogonal test analysis, the layer thickness ratio is the most sensitive to the uniaxial compressive strength. The optimal combination is obtained by analysis as follows: layer thickness 6 cm, layer thickness ratio 0.1, and rock layer inclination angle 0°.