Unloading-induced slip of jointed surfaces reinforced with slurries of different water-cement ratios experimental study
In order to investigate the effect of different water-cement ratio slurry reinforcement on the slip characteristics of granite joint faces under unloading-induced slip conditions,this test was conducted on granite joint faces reinforced with various water-cement ratios of cement slurry to carry out constant axial pressure graded unloading of circumferential pressure-induced slip tests.The test results show that:(1)The three-dimensional morphology scanning of the unfilled joint surface revealed that the arithmetic mean height Sa,root-mean-square height Sq and kurtosis coefficient Sku of the joint surface were 5.744,7.554 and 11.106 before slip,and 13.999,17.586 and 5.431 after slip.The height difference of the surface of the joint surface increases,and stripe cuts gradually disappears.(2)Using SEM(scanning electron microscope)to observe the microstructural damage surface of the reinforced joint surface,it was found that with the increase of water-cement ratio,the strength of the cement skeleton decreased,the fluidity of the slurry increased,and the microscopic damage form of the cement-rock structural surface was changed.(3)The peak shear stresses under the same circumferential pressure were 28.067,15.609 and 8.863 MPafor0.5,0.7 and 1.0 slurry-reinforced joints,and the shear displacements at the induced slip stage were 0.072,0.050 and 0.061 mm in that order.the shear strength and the ability of the joints to resist slip deformations were both improved.(4)The reinforced joint surface generates energy consumption through creep-slip,which improves the stick-slip phenomenon.According to the analysis of the test results:the smaller the water-cement ratio is,the more energy is dissipated through creep in the cement-rock interlocking structure.When the water-cement ratio is 0.7,the undisturbed creep sliding speed is the lowest,and the slip stability of the formed interlocking structure is stronger.
rock mechanicsunloading-induced slipwater-cement ratioslip characteristicsgrouting reinforcement
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