辉绿岩裂隙注浆体力学特性试验研究

Experimental study on mechanical properties of diabase fracture-grouting mass

为了分析裂隙几何形态对注浆后岩体力学特性的削弱影响规律,通过切割辉绿岩预制不同的裂隙倾角、裂隙贯通程度和裂隙条数,设计裂隙岩样简易注浆模具并进行室内注浆试验,开展辉绿岩原岩及其裂隙注浆体的单轴、常规三轴压缩试验,较全面地分析不同裂隙几何形态下辉绿岩裂隙注浆体的应力–应变关系及力学特性。主要结论有:(1)裂隙中充填水泥浆体以及围压作用明显改变了岩样的应力–应变关系,由原岩典型弹脆性转变为弹性–一定范围内塑性–脆性或理想弹塑性,除发生沿裂隙面滑移破坏情况外,均显著提高了峰后区延性;(2)裂隙显著地降低了岩样的力学性质,呈现出明显的各向异性,在低围压、全贯通、裂隙倾角60°时力学性质最差,处于最不利状态,为岩体隧道工程中选线定向、强度参数选取提供理论参考依据;(3)全贯通条件下岩样破坏以岩块沿裂隙面发生较大剪切滑移变形为主、岩块沿纵–斜向的张拉–剪切裂纹为辅,半贯通条件下岩样破坏首先源于裂纹尖端起裂,然后裂纹追踪最大主应力的方向而导致贯通或裂纹追踪剪切面达到其抗剪强度而剪切破坏。为相应的裂隙岩体(岩石)力学工程设计与施工提供指导,具有一定的理论价值与工程实际意义。

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.