新延安隧道层状页岩力学性能试验研究

为研究新延安隧道层状页岩的力学特性和破坏特征,分析层理面不同倾角对岩石力学参数的影响,分别进行了不同层理角度下的室内单轴压缩、三轴压缩和巴西劈裂试验及数值单轴压缩和三轴压缩试验。室内试验分析表明：峰值强度随倾角增加呈先减小后增大的趋势;抗压强度呈“U”型趋势,弹性模量呈“V”型变化。通过大量数值模拟试验拓展了室内试验范围并分别拟合了抗压强度和弹性模量随倾角变化关系式;围压的增大弱化了页岩各向异性,但随着围压的不断增大弱化程度减小;黏聚力对层状页岩强度的弱化程度远远大于内摩擦角;抗拉强度随倾角的增大逐渐减小;倾角不同层状页岩的破坏模式也不同,单轴压缩时,0°为张拉破坏,30°～60°时发生由弱面控制的沿层理面发生的剪切滑移破坏,90°时产生劈裂张拉破坏。三轴压缩时不同层理面倾角的页岩试件主要发生剪切破坏。

Experimental Study on the Mechanical Performance of Layered Shale in New Yan 'an Tunnel

In order to study the mechanical properties and failure characteristics of layered shale in New Yan ''an tunnel and analyze the influence of different inclination angles of bedding plane on rock mechanical parameters. Laboratory uniaxial compression, triaxial compression and Brazil splitting tests and numerical uniaxial compression and triaxial compression tests under different bedding angles are carried out in this paper. The laboratory test analysis show that: the peak intensity first decreases and then increases with the increase of inclination Angle. The compressive strength shows a U-shaped trend, The elastic modulus changes in a "V" shape. And through a large number of numerical simulation tests to expand the scope of laboratory tests and the relationships between compressive strength and elastic modulus with dip Angle were fitted respectively. The increase of confining pressure weakens shale anisotropy, but the degree of weakening decreases with the increasing of confining pressure. The strength of laminated shale is weakened by cohesion much more than internal friction Angle. The tensile strength decreases with the increase of inclination Angle. The failure modes of layered shale are different with different inclination angles, under the condition of uniaxial compression, tensile failure occurs for 0°, shear slip failure along the bedding plane controlled by the weak plane occurs at 30°~60°, cleavage tensile failure occurs at 90°. Under triaxial compression, the shale specimens with different bedding plane inclinations mainly undergo shear failure.