紫坪铺库区断层分布规律统计分析

定量描述地质构造的分布规律对诸如核废料地质处置、边坡稳定性分析、采矿工程以及水利水电工程都具有十分重要的意义。本文根据紫坪铺水库工程区域地质图,通过提取断层信息的方法,获得了断层分布图。对紫坪铺水利枢纽工程库区内尺度跨越3个数量级、共126条断层进行了统计分析,获得了断层长度-数量间的幂律关系,即N(r)~r^-D。并通过分段线性拟合的方法,计算了幂指数的值。发现当断层长度r<2.5km时,幂指数D=0.32;而当断层长度r≥2.5km时,幂指数D=1.58。该幂律关系对推演更小或更大规模断层分布具有重要意义。

STATISTICAL ANALYSIS OF FAULT DISTRIBUTION AND LENGTHS AT ZIPINGPU HYDROPOWER PROJECT

It is important for rock engineering such as nuclear waste disposal, slope stability, mining engineering and hydropower project to describe quantitatively the distribution of geological faults. A distribution diagram of faults is obtained from the geological diagram at Zipingpu Hydropower Project. The data set of 126 faults at the site is analyzed statistically. The fault lengths are found to have a distribution of three orders of magnitudes. . A power-law relation between the fault number and the fault length is proposed, i.e., N(r)~r^-D. Two power exponents are estimated by using linear fit in two segments. It is found that the power exponent has a value of 0.32 if faslt lengths are shorter than 2.5km. The power exponent is equal to 1.58 if fault lengths are longer than 2.5 km. It is suggested that the power-law relation between fault number and fault length is of a significant importance for extrapolation of a fault distribution to either further small or further large scales.