基于小波变换理论的岩石节理面粗糙度分级表征  

Hierarchical characterization joint surface roughness coefficient of rock joint based on wavelet transform

作　　者：元宙昊 叶义成[1,2] 罗斌玉 阎要锋 YUAN Zhouhao;YE Yicheng;LUO Binyu;YAN Yaofeng(School of Resource and Environmental Engineering,Wuhan University of Science and Technology,Wuhan 430081,China;Industrial Safety Engineering Technology Research Center of Hubei Province,Wuhan University of Science and Technology,Wuhan 430081,China;School of Civil Engineering and Architecture,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]武汉科技大学资源与环境工程学院,湖北武汉430081 [2]武汉科技大学湖北省工业安全工程技术研究中心,湖北武汉430081 [3]武汉理工大学土木与建筑工程学院,湖北武汉430070

出　　处：《煤炭学报》2022年第7期2623-2642,共20页Journal of China Coal Society

基　　金：湖北省重点研发计划资助项目(2020BCA082);湖北省自然科学基金资助项目(2020CFB123);湖北省教育厅科学技术研究资助项目(Q20201109)。

摘　　要：岩石节理面粗糙度的准确量化表征一直是节理岩体力学领域关注的热点问题。节理面表面形貌是多尺度的,且一阶、二阶起伏体对节理面粗糙度的形貌贡献存在差异,如何在考虑节理面多尺度特征的前提下实现粗糙程度的准确表征有待深入研究。基于小波变换理论,提出了用于小波基优选的能-熵比准则,结合基于能量保持百分比及信号标准差定义的临界分解水平准则,形成了节理面形貌分解理论。然后,以节理面形貌分解理论为基础,以10条标准节理面粗糙度系数(JRC)曲线为对象,实现了标准曲线中一阶、二阶起伏体的准确分离。对一阶、二阶起伏体的统计参数(一阶导数均方根Z_(2)、节理面粗糙度指数R_(p)-1)进行了计算,分析了一阶、二阶起伏体统计参数之间的差异,揭示了标准曲线的统计参数随粗糙度增加而出现局部凸起现象的原因,建立了节理面粗糙度的分级表征公式。最后,开展节理面剪切试验对粗糙度分级表征公式的可靠性进行验证。研究结果表明:①基于小波基优选准则确立的最优小波基coif5可实现节理面表面形貌的小波变换处理;②基于临界分解水平判别准则确立的第4分解水平适用于一阶、二阶起伏体的识别;③节理面中一阶、二阶起伏体的统计参数存在差异,二阶起伏体的统计参数普遍大于一阶起伏体的统计参数,揭示了标准曲线的统计参数随粗糙程度的增加而出现局部凸起的主要原因是未考虑一阶、二阶起伏体的形貌贡献差异;④基于粗糙度分级表征公式得出的节理面粗糙度系数与节理试样剪切试验结果的反算值吻合,且准确度比未分级的表征公式要好,表明粗糙度分级表征公式是合理的。How to quantize the characterization of joint roughness accurately has always been an issue in the field of joint rock mechanics.Joint surface morphology is multi-scale,and the contribution of waviness and unevenness to the joint surface roughness is different.Under the premise of considering the multi-scale characteristics of the joint surface,how to realize the accurate characterization of the joint surface roughness needs further research.The wavelet-based optimization criterion was proposed based on the energy-entropy ratio.The critical decomposition level criterion was defined based on the energy retention percentage and the signal standard deviation.Combined with wavelet transform theory,the theory of joint surface morphology decomposition was developed.Based on the decomposition theory,ten standard JRC profiles was taken as objects to realize the accurate decomposition of the joint surface morphology.The statistical parameters of the waviness and unevenness(first-order derivative root mean square Z_(2),joint surface roughness index R_(p)-1)were calculated,and the differences between them were analyzed,revealing the reason why the statistical parameters appear to be locally convex with the increase in roughness.Then,a hierarchy characterization formula was established based on the statistical parameters.Finally,the formula was verified by the shear test of the joint specimen.The results are as follows:①The optimal wavelet basis coif5 determined based on the wavelet base optimization criterion can be used for the wavelet transform of joint surface morphology.②The fourth decomposition level determined based on the critical decomposition level criterion is suitable for the identification of waviness and unevenness.③The statistical parameters of the waviness and unevenness are different,and the statistical parameters of the unevenness are larger than those of the waviness.The phenomenon that the statistical parameters appear to be locally convex with the increase in roughness when the statistical paramete

关 键 词：小波变换 粗糙度分解 节理面粗糙度系数(JRC) 分级表征 统计参数 

分 类 号：TD315[矿业工程—矿井建设]