岩体节理平均迹长估计

MEAN TRACE LENGTH ESTIMATION OF ROCK MASS JOINT

分析总结岩体节理平均迹长的估计方法后,扩展了测线法节理平均迹长估计的理论基础。扩展后的测线法在相同的现场节理调查数据下,可更加准确地估计岩体节理的平均迹长。同时指出,采用圆形窗口法平均迹长估计时,假设迹线中点在窗口中均匀分布与实际情况偏差很大,为避免迹线中点不均布的情况必须保证窗口的尺度足够大。随着圆形取样窗口的增大,迹线中点密度在窗口中的变化减小,估计所获得的节理平均迹长的准确度较高。通过现场节理调查获得丰富的节理数据,采用扩展的测线法和圆形窗口法分别估计岩体节理的平均迹长。当圆形窗口的直径与测线法删节长度相等时,扩展测线法和圆形窗口法估计所得的岩体节理平均迹长比较接近,由此可确定研究区域的岩体节理平均迹长。

After the method of mean trace length estimation of rock mass joint was analyzed and summarized, the theory basis of mean trace length estimation by scanline method was extended. The extended scanline method can estimate mean trace length much more exactly in case there is not a great deal of data which are surveyed in field. As for the circular window method, there is a large error between the assumption that the trace midpoint density distribution is uniform in the survey window and the actual density distribution. The window scale must be large enough to guarantee that the distribution of trace midpoint is uniform. The diversity of trace midpoint density decreases, and the estimation of mean trace length is more exact as the radius of circular sample window increases. Aburidant joint data were obtained through field survey. The mean trace length of rock mass joint was estimated by the extended scanline method and circular window method. When the diameter of circular window is equal to the censored length with scanline method, the mean trace length estimated by scanline method is close to that estimated one by circular window method. Thus, the mean trace of rock mass joint can be obtained.