APPLICABILITY OF FRACTAL CHARACTERIZATION AND MODELING TO ROCK JOINT PROFILES
APPLICABILITY OF FRACTAL CHARACTERIZATION AND MODELING TO ROCK JOINT PROFILES
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DOI：
10.1016/0148-9062(92)92120-2
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发表时间：
1992-03-01
期刊：
影响因子：
--
通讯作者：
SPECK, RC
中科院分区：
文献类型：
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作者：
HUANG, SL;OELFKE, SM;SPECK, RC
利用随机中点位移法、谱综合法和确定性分形几何方法生成了已知维分数布朗运动的合成记录。通过检验具有已知分维的合成FBM记录的计算维度，评估了用于测量自仿射记录的分维的方法的有效性。采用了两种分维分析方法(即变异函数和周期图)来确定轮廓的分维。对FBM记录的周期图的分析表明，预白化数据的预期维度和计算维度之间具有较高的相关性。这些FBM记录的变异函数显示出较好的准确性，同时滞后较小(即约合成轮廓长度的10%)用于测量。也使用激光轮廓术来测量接头粗糙度。几个天然岩石节理平行于节理面取芯。然后用激光轮廓仪对岩芯进行了分析，用变异函数和周期函数测得的天然节理轮廓的分维值在1.3到1.4之间。然而，周期图法比变异函数法产生的维度略高。利用分形插值函数生成已知尺寸的合成关节轮廓，以提供与自然关节的定性比较。计算机生成的轮廓被发现模仿了天然岩石节理的许多视觉特征。
Synthetic records of fractional Brownian motion (fBm) with known dimensions were generated using random midpoint displacement, spectral synthesis and deterministic fractal geometry methods. The validity of the methods used to measure the fractal dimensions of self-affine records was evaluated by examining the calculated dimensions of the synthetic fBm records with known fractal dimensions. Two methods of fractal analysis (i.e. variogram and periodogram) were employed to determine the fractal dimensions of the profiles. Analysis of periodograms of fBm records revealed a higher correlation between the expected and calculated dimensions of pre-whitened data. Variograms of those fBm records indicated a better accuracy while smaller lag (i.e. approx. 10% of the profile length) of the synthetic profile length was used for determination.Laser profilometry was utilized as well to provide the measurement of joint roughness. Several natural rock joints were cored parallel to the joint faces. The cores were then analyzed with a laser profilometer for asperity measurement The fractal dimensions of the natural joint profiles determined by using variograms and periodograms ranged from 1.3 to 1.4. The periodogram method, however, produced slightly higher dimensions than did the variogram method. Synthesized joint profiles of known dimensions were generated using fractal interpolation functions to provide a qualitative comparison with the natural joints. The computer generated profiles were found to mimic many of the visual characteristics of natural rock joints.