| In actual rock engineering,most of the failures of jointed rock masses are along the joint plane,and filled rock joints are widely present in nature,which causes the mechanical effects of rock mass strength and deformation to be far lower than the rock itself.Therefore,the study of filling rock the shear strength and damage of joints are of great significance.In this paper,the following researches are carried out by combining the indoor direct shear test of the filled rock joints and the digital image processing of the failure characteristics of the joints:（1）Prepare cement grout type rock joint specimens with morphology characteristics of the 5th to 10th Barton standard profile lines,use quartz sand as the filling medium,and set8 filling degreesΔto obtain cement grout type rock joint specimens.Through direct shear test,the variation law of the peak shear strength of the filled rock joints with the filling degree is obtained.The results show that the peak shear strength of the filled rock joint specimens with different surface roughness decreases with the filling degree.Trend,eventually tends to the shear strength of quartz sand,the corresponding filling degree is the critical filling degreeΔcr,and its value is 1.50;（2）Using digital image processing technology to process the shear failure characteristics of the joint surface of the filled rock after shearing,calculate the joint surface shear area ratio Rs,and obtain the change rule of the joint surface shear area ratio Rs with the filling degree,the result It shows that the shear area ratio Rs gradually decreases with the increase of the filling degree,until the filling degree reaches the critical filling degree 1.50,the shear area ratio Rs tends to a fixed value,and both follow Rs=m×exp（-n×Δ）The law of change;（3）According to the results of the indoor direct shear test,the shear strength criterion of the filled rock joints considering the influence of the filling degree is established:（?）... |
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