Mechanical and Hydromechanical Behaviour of Hard Rock Joints. A laboratory study
Mechanical and Hydromechanical Behaviour of Hard Rock Joints. A laboratory study
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硬岩节理的机械和流体力学行为。
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
R. Olsson
中科院分区：
文献类型：
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作者：
R. Olsson
作为岩石工程的结果，岩体会因应力变化而变形。大多数变形以法向应变和剪切应变的形式发生在岩石节理中。这些变形还将改变空隙的几何形状，从而改变接头孔径和流体流动。该研究的目的是增加对岩石节理机械和水力学行为的认识和理解，并提供必要的参数值。对花岗岩接头和复制品进行了全面的实验室测试程序，然后进行了分析。复制品由高强度混凝土组成，其岩石力学参数与花岗岩样品接近。使用 19 个花岗岩样品之一的印模，在橡胶模具中铸造了 36 个相同的复制品。除其他方法外，还使用激光轮廓仪进行粗糙度测量。根据测量的轮廓线，尝试使用分形维数 (D) 作为接头粗糙度的量度。大多数机械和流体力学实验室测试都是在直剪箱中进行的。在剪切测试之前，进行正常的加载和卸载循环以加固接头。剪切试验是在恒定法向载荷 (CNL) 和恒定法向刚度 (CNS) 下进行的。为了为（CNS）剪切试验提供相关的岩体刚度，提出了一个模型。 CNL 和 CNS 测试之间的剪切应力路径和峰值剪切刚度存在明显差异，而膨胀角和峰值摩擦角不受影响。在水力剪切试验中，流过接缝的水流是平行的；接头的开口比液压孔径大得多，这当然取决于接头表面退化产生的凿痕。进行了小型建模练习以验证从剪切测试中获得的一些结果。
As a consequence of rock engineering works, the rock mass will deform due to stress changes. Most deformation occurs in the rock joints, in form of normal and shear strains. These deformations will also change the void geometry and thereby the joint aperture and fluid flow. The purpose of the study was to increase the knowledge and understanding about mechanical and hydro-mechanical behaviour of rock joints and to provide essential parameter values. A comprehensive laboratory test programme was performed on both granite joints and replicas, followed by an analysis. The replicas consisted of high strength concrete with rock mechanical parameters close to those of the granite samples. 36 identical replicas were cast in a rubber mould, using an impression from one of the 19 granite samples. Roughness measurements were performed with, among other methods, a laser profilometer. Based on measured profile lines, an attempt was made to use fractal dimension (D) as a measure of joint roughness. Most of the mechanical and hydromechanical laboratory tests were performed in a direct shear box. Before shear testing, normal loading and unloading cycles were performed to consolidate the joints. The shear tests were performed with both constant normal load (CNL) and constant normal stiffness (CNS). To provide relevant rock mass stiffness for the (CNS) shear tests, a model was suggested. A clear difference between CNL and CNS tests occurred in the shear stress paths and in the peak shear stiffness, while the dilation angle and peak friction angle were unaffected. In the hydromechanical shear tests, the water flow through the joint was parallel; the joint opened much more than the hydraulic aperture which certainly depends on gouge production from the degradation of the joint surfaces. A minor modelling exercise was performed to verify some results obtained from the shear tests.