现有结构面剪切强度参数经验估算公式多建立在结构面形态二维描述基础上,对结构面形态的三维特征考虑不够.作者自行研制了结构面形态三维量测设备,对结构面表面形态进行三维量测,将量测结果与分形理论相结合,采用分形维数表征结构面三维形态特征.在对大量硬性结构面剪切试验结果及表面形态描述结果进行统计分析的基础上,提出将JRC-JCS估算公式中的JRC用分形维数的表达式替换,进而建立了基于结构面表面形态三维分形表述的剪切强度估算公式:r=σn.tg[(6.12D-3.53)lg(JCS/σn)+ψb].小实际应用结果表明,改进后的估算方法能得到令人满意的结构面剪切强度参数.%Estimation method can effectively make up the shortages of testing method in determining the shear strength of hard joint. While, the estimation methods commonly used nowadays are all formed based on 2-D shape of joint, and the 3-D character of joint surface is ill-considered. To solve this problem, a new kind of simple measuring equipment which can be used to get 3-D shape of joint surface was manufactured. And then, the fractal method was used to describe the 3-D shape of joint surface. The index of JRC in JRC-JCS formula which was brought forward by Barton in 1977 was replaced by function of fractal dimension D, and thefollowing estimation formula was formed: τ =σ n tg [(6. 12D - 13. 53) lg(JCS/σn)+ φb]. The improved estimationformula can consider the 3D effect effectively. Application result indicted that the improved estimation formulawas satisfying.
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