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In order to investigate the
influence of oblique compression shear method and conventional triaxial test to
the test results, the red sandstone and marble were tested by the oblique
compression shear method on INSTRON1346 and the conventional triaxial test on
MTS815. It was found that the shear strength parameters, cohesion and internal friction
angle was less than the
conventional triaxial test. Low cohesion was mainly because the
sample shear force in the oblique compression shear test in 2D, but in
conventional triaxial test he sample was stressed in 3D. Meanwhile, in the
oblique compression shear test the rigid contact between sample and mould caused
torsion. The result of cohesion by oblique compression
shear method was less than by conventional triaxial test. The low degree of red
sandstone is about 4.6 times of marble. As the brittleness of red sandstone is
higher than that of marble, leading to cut stress decomposition. When the tilt
angle was low, rock prone torque and shear stress decomposition, so the shear
force increased and declined. Therefore,
in the oblique compression shear test of brittle materials should be increased
the tilt angle. Lastiy, in order to avoid the damage of rock, When the rock is
in two dimensional stress conditions, we should control the load limit rather
than the limit of displacement control. When the rock is in three dimensional
stress conditions, we can control the load limit and displacement loading
limit, which provide convenience to choose the method of measuring the shear
strength of rock reasonably