乌鲁木齐地铁隧道互层岩体力学特性及几何特征因子敏感性模拟

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

为研究地铁隧道中软硬互层岩体力学特性及破坏机制,本文首先在乌鲁木齐泥岩、砂岩物理力学参数获取的基础上,对互层岩体物理力学参数进行微观参数标定,然后通过颗粒流数值模拟单轴压缩试验,分析互层岩体层厚、层厚比、岩层倾角作用下互层岩体强度响应规律及裂纹变化。分析结果表明:随着互层岩体层厚的增加,其单轴抗压强度在降低,裂纹数量也在降低,裂纹发展速度加快;随着互层岩体层厚比的增加,其单轴抗压强度在不断降低,在层厚比大于1时单轴抗压强度的变化相对稳定,且层厚比小于0.6时裂纹发展趋势较为快速,层厚比大于0.6时裂纹发展趋势较为缓慢;互层岩体岩层倾角的增加使单轴抗压强度的变化大体呈U字形变化趋势,40°时单轴抗压强度最低,90°时裂纹数量最多,发展趋势最为缓慢;由正交试验分析得出层厚比对单轴抗压强度敏感性最大,并分析得出了最优组合;最优组合为:层厚6 cm、层厚比0.1、岩层倾角0°。

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°.