Study Of Joint Surface Topography And Application In Strength Criterion Of Rockmass Containing Discontinuous Joints

In this dissertation, the assessment of surface roughness is studied in detail. Based on the parameters of the 2D assessment of surface roughness, the method of 3D assessment is proposed, which can express the character of the joint faces much more rationally and accurately than 2D assessment. A contact algorithm is proposed and realized by programming. The algorithm can make two joint faces' datum touch with each other stably, then the datum of combined morphology can be obtained easily. The 3D profiles of two manual joints are measured using TJXW—3D Rock Surface Measurement Instrument, and are analyzed by using the parameters of the 2D assessment and the parameters of the 3D assessment at the same time.Basing on laboratory direct shear test, the failure mechanism and strength behavior of brittle rock mass containing coplanar close discontinuous joints under shear condition are analyzed. A modified criterion of failure strength are proposed, according to the results of laboratory direct shear test, and the modified criterion can explain the phenomenon in direct shear test, and the calculated results according to the modified criterion of failure strength agree well with experimental results.In the finality, the problems requiring further studies are discussed.