(1. Engineering Center，China Academy of Transportation Sciences，Beijing 100029，China；
2. School of Civil Engineering，Beijing Jiaotong University，Beijing 100044，China)
Abstract：In order to analyze the influence of fracture geometry on the weakening of mechanical properties of rock mass after grouting，different crack inclination angle，crack penetration degree and number of cracks were prefabricated by cutting diabase. A simple grouting mold for fractured rock samples was designed and applied for indoor grouting test. The uniaxial and conventional triaxial compression tests of the diabase and its fracture-grouting mass and the indoor grouting test of the fractured rock samples were carried out. The stress-strain relationship and mechanical properties of diabase fracture-grouting mass under different fracture geometries were analyzed comprehensively. The main conclusions are：(1) Filling the cement slurry in the fracture and confining pressure significantly change the stress-strain relationship of the rock sample，from the typical brittleness of the original rock to the elastic-within a certain range plastic-brittle or ideal elastoplasticity. In addition to the occurrence of slippage along the fracture surface，the ductility of the post-peak zone is significantly improved；(2) The fracture significantly reduces the mechanical properties of the rock sample and the fracture-grouting mass exhibits obvious anisotropy. The mechanical properties are the worst at low confining pressure，full penetration，and 60°crack inclination angle in the most unfavorable state. Providing theoretical reference for selecting line orientation and strength parameters in rock mass tunnel engineering；(3) The rock sample failure under full penetration conditions is dominated by large shear-slip deformation along the fracture surface，and is supplemented by longitudinal-oblique tension-shear cracks；the rock sample failure under semi-through conditions firstly originates from the crack tip cracking，and then the crack tracks the direction of the maximum principal stress，which causes the penetration，or crack tracking shear surface to reach its shear strength and shear failure. It provides guidance for the design and construction of the corresponding fractured rock mass (rock) mechanical engineering，which has certain theoretical value and practical engineering significance.
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2020, Vol. 39 
