含倾斜软弱夹层砂岩力学特性试验

Experimental Study on Mechanical Properties of Sandstone with Inclined Soft Intercalation

为研究不同倾角软弱夹层对砂岩强度和变形的影响,预制含有不同倾角(15°,30°,45°,60°)软弱夹层的砂岩试件及完整砂岩试件进行单轴压缩试验.试验研究发现,软弱夹层对砂岩的强度具有明显的削弱效果,在0°～60°的倾角范围,随着软弱夹层倾角的增加,这种削弱效果更加显著;弹性模量和泊松比随着软弱夹层倾角的增大而减小,当软弱夹层倾角达到45°时,弹性模量和泊松比出现"跳跃式"减小;完整试件的破坏形式是常见的压-剪破坏,含软弱夹层的试件,随着软弱夹层倾角的增加,试件的破坏形式由拉-剪复合破坏向沿着软弱夹层面剪切破坏转变,在45°～60°范围内,软弱夹层倾角越大,沿软弱夹层面发生剪切破坏越明显.

In order to study the influence of different dip angle weak intercalation on sandstone strength and deformation, uniaxial compression tests are carried out on sandstone specimens with different dip angles (15, 30, 45 and 60 degrees) weak interlayer and intact sandstone specimens. Experimental research finds that the strength of sandstone is weakened obviously by weak interlayer, and the weakening effect is more remarkable with the increase of dip angle of weak interlayer in the range of 0 to 60 degrees. Modulus of elasticity and Poisson ratio decrease with increasing dip of soft sandwich, they appear to "jump" reduction when the soft sandwich dip reaches 45 degrees;the failure form of intact specimen is pressure-shear failure, with the increase of the dip angle of the specimen with weak intercalation, the failure mode changes from the pull-shear composite failure to the shear failure along the weak clip layer, the greater the dip angle of the weak intercalation, the more obvious the shear failure along the soft sandwich layer in the range of 45 to 60 degrees.