Abstract
There are a large number of discontinuous weak planes distributed in the natural rock mass, which makes the sliding failure of rock mass along the intermittent structural plane very complex. To investigate the shear failure mechanism of rock mass with intermittent joints and study the influence of different joint heights on the shear failure mode of the rock mass, direct shear tests were carried out by presetting a series of jointed rock specimens with different undulating heights. During the shear loading, digital image correlation (DIC) technology was employed to monitor the surface strain field of the specimens in real time. The results show that the fluctuation height has a significant effect on the evolution of shear strain. With the increase of shear load, the maximum shear strain of the jointed specimens with different undulating heights first increases slowly and then increases rapidly. When the undulating height is 5 mm, the failure of the specimen is dominated by the rock sliding along prefabricated joints. When the undulating height is larger than 10 mm, the shear fracture of the rock becomes dominant. With the increase of the undulating height, more penetrating cracks perpendicular to the preexisting joints appear between the serrated surfaces, and the shear fracture phenomenon is more obvious.
Highlights
When a rock mass shears along a structural plane, the shear resistance of the structural plane is affected by the structural plane undulations and by the friction between the contact regions [1,2,3]
Intermittent joints are widely distributed in the rock mass for both slopes and underground spaces, and the mechanism of sliding failure caused by intermittent joints is often very complex [4,5,6,7]. erefore, the research on the shear mechanical properties and deformation characteristics of discontinuity rock mass is one of the important scientific problems in the field of engineering geology and rock mechanics [8,9,10]
Direct shear test is an effective method to study the effect of shear stress on jointed rock mass
Summary
When a rock mass shears along a structural plane, the shear resistance of the structural plane is affected by the structural plane undulations and by the friction between the contact regions [1,2,3]. As early as 1969, Lajtai [11, 12] studied the failure mode of jointed gypsum through direct shear test. He divided the failure mode of jointed gypsum into three types: tensile failure, shear failure, and compressive failure. Direct shear test is an effective method to study the effect of shear stress on jointed rock mass. It can simulate the stress state of jointed rock mass when it is destroyed in nature. Yang et al [15] carried out uniaxial compression test on fractured fine sandstone with different shapes and analyzed the influence of fracture on rock mass failure mode
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