集宁板岩岩爆碎屑分形特征分析

Fractal Characteristics of Fragments Generated from Rockburst Test on Slate Taken from Jining

为了补充板岩的岩爆试验研究,利用深部岩爆模拟试验系统对内蒙古集宁板岩进行了室内岩爆试验,通过三向加载—分级卸载—垂向加载来模拟板岩岩爆的发生。收集岩爆碎屑进行筛分,对粒径〉10 mm的碎屑按不同的岩块形态的衡量指标,分别计算其分形维数。结果表明：岩块形态的衡量指标对板岩岩爆的碎屑分维值有一定的影响,分维值分布在1.62-2.73之间,且按长度/宽度/厚度-数量计算得到的分维值离散性最小,可作为计算板岩岩爆碎屑分维值的优选衡量指标;厚度、长度、宽度3个方向的破碎难度依次增强;长宽比、长厚比和宽厚比与数量分维值可表征碎屑的条状、片状、块状特征,板岩岩爆碎屑以条状、条块状和块状为主,片状特征不明显。

In order to replenish the study of slate＇ s rockburst test, we carried out indoor rockburst test on slates from Jining by loading in three directions, gradual unloading from one surface, and then vertical gradual loading to simulate the rockburst of slate using deep rockburst simulation test system. Then we collected and screened the rockburst fragments, and calculated the fractal dimensions of fragments of particle size greater than 10mm according to different forms of rock. The results indicate that different forms of rock have influence on the fractal dimension which ranges from 1.62-2.73. The fractal dimensions of length, width, and thickness to quantity have the smallest discrete and can be taken as the preferred indicators. The degree of broken difficulty in thickness, length, width is enhanced gradually. In addition, the fractal dimensions of ratios of length to thickness, length to width and width to thickness could characterize strip, sheet, and block of fragments,respectively. The results of the test indicate that slate rockburst fragments are mainly strip, strip-block and block and the sheet feature of fragments is unobvious.