The scale dependence of rock joint surface roughness
The scale dependence of rock joint surface roughness
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DOI：
10.1016/s1365-1609(01)00028-4
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发表时间：
2001-07-01
影响因子：
7.2
通讯作者：
Jing, LR
中科院分区：
文献类型：
--
作者：
Fardin, N;Stephansson, O;Jing, LR
岩体节理表面粗糙度的大尺度精确测定是岩体表征的基础。岩石节理的表面粗糙度通常使用小样本来表征。然而，由于岩石节理的粗糙度参数与尺度有关，其描述符随尺度变化。为了了解岩石节理表面粗糙度的尺度效应，进行了系统的研究。一个硅橡胶复制品。尺寸为1000 mm x 1000 mm，由天然岩石节理表面原位模制而成，并在实验室中使用具有高精度和分辨率的3-D激光扫描仪对其表面进行数字化。基于粗糙度-长度法计算了描述复型表面粗糙度的分形参数，即分形维数D和振幅参数A。为了研究岩石节理表面粗糙度的尺度依赖性，从复制品的中心部分选择了10个尺寸从100 mm x 100 mm到1000 mm x 1000 mm的采样窗口，并计算了它们的分形参数。结果表明，D和A都是尺度相关的，它们的值随着采样窗口大小的增加而减小。这种规模依赖性被限制在一定的大小，定义为平稳性阈值。对于大于平稳阈值的采样窗口，估计参数几乎保持不变。结论是。为了在实验室规模或现场准确表征表面粗糙度，样品需要等于或大于稳定性极限。在本文中，我们指出了方法，建立的值为稳定性限制岩石节理。(C)2001爱思唯尔科技有限公司版权所有。
Accurate determination of surface roughness of rock joints at the large-scale is essential for proper rock mass characterization. Surface roughness of rock joints is commonly characterized using small samples. However, since roughness parameters of rock joints are scale-dependent and their descriptors change with scale. a systematic investigation has been carried out to understand the effect of scale on the surface roughness of rock joints. A silicon rubber replica. 1000 mm x 1000 mm in size, was Moulded in-situ from a natural rock joint surface and its surface was digitized in the laboratory using a 3-D laser scanner having high accuracy and resolution. The fractal parameters, i.e. the fractal dimension D and amplitude parameter A describing surface roughness of the replica, were calculated on the basis of the Roughness-Length Method. To investigate the scale-dependency of surface roughness of rock joints, ten sampling windows ranging in size from 100 mm x 100 mm to 1000 mm x 1000 mm were selected from the central part of the replica and their fractal parameters were calculated. The results show that both D and A are scale-dependent and their values decrease with increasing size of the sampling windows. This scale-dependency is limited to a certain size, defined as the stationarity threshold. and for sampling windows larger than the stationarity threshold, the estimated parameters remain almost constant. It is concluded that. for surface roughness to be accurately characterized on a laboratory scale or in the field, samples need to be equal to or larger than the stationarity limit. In this paper we have indicated the methodology for establishing the value for the stationarity limit for rock joints. (C) 2001 Elsevier Science Ltd. All rights reserved.