乌鲁木齐地铁隧道互层岩体力学特性的离散元数值分析

Distinct Element Numerical Analysis of Mechanical Properties of Interlayer Rock Mass in Urumqi Subway Tunnel

为了研究乌鲁木齐地铁隧道中强风化泥岩、砂岩组成的互层岩体力学特性,首先在乌鲁木齐强风化泥岩、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,分析了互层围岩层厚、层厚比、岩层倾角及层厚比与岩层倾角共同作用下互层岩体力学特性响应规律。分析结果表明:互层围岩的层厚与单轴抗压强度负相关;随着互层围岩层厚比的增加,其单轴抗压强度在降低,且下降梯度逐渐减小;互层围岩倾角的增加使单轴抗压强度的变化大体呈U形变化趋势,在岩层倾角为40°时,单轴抗压强度达到最低;围岩倾角与层厚比的组合对单轴抗压强度的影响比较明显,且在围岩倾角为0°、20°、80°,围岩层厚比为0~0.2最为显著。综合分析,互层岩体力学特性较为复杂,不同层厚、层厚比、岩层倾角及围岩倾角与层厚比的组合所表现出的力学差异显著,需要在实际工程中遇到具体问题具体分析。

To study the mechanical properties of interlayer rock mass composed of strongly weathered mudstone and sandstone in Urumqi subway tunnel,first,based on the acquisition of physical and mechanical parameters of Urumqi mudstone and sandstone,the micro-parameters of the physical and mechanical parameters of interlayer rock mass were calibrated.Secondly,through the uniaxial compression test of particle flow code numerical simulation,the response of mechanical properties of interlayer rock mass under the actions of thickness,thickness ratio,dip angle,both thickness ratio and dip angle of interbedded rock,were analyzed.The results show that the layer thickness of the interlayer rock was negatively correlated with its uniaxial compressive strength.When thickness ratio of the interlayer rock increased,the uniaxial compressive strength decreased and its gradient decreased.With the increase in dip angle of the interlayer rock,the change of uniaxial compressive strength tended U-shaped,and the uniaxial compressive strength reached the lowest when the rock dip angle was 40°.The combination of dip angle and thickness ratio of interlayer rock has obvious influence on uniaxial compressive strength,and it is most significant when the dip angle of interlayer rock was 0°,20°and 80°,and the thickness ratio of interlayer rock was 0~0.2.Comprehensive analysis showed that the mechanical properties of interlayer rock masses were relatively complex.The mechanical differences are significant,which exhibited by the different layer thicknesses,layer thickness ratios,rock dip angle,combinations of rock dip angle and layer thickness ratios,and specific problems encountered in actual engineering need to be analyzed in detail.