Statistical analysis of distribution patterns of coal seams in fold zones in Northwest China
Statistical analysis of distribution patterns of coal seams in fold zones in Northwest China
复制标题
西北地区褶皱带煤层分布规律统计分析
DOI：
10.1016/j.ijmst.2018.09.003
复制
发表时间：
2018
影响因子：
11.8
通讯作者：
Zhang Chengguo
中科院分区：
文献类型：
--
作者：
Cao Anye;Jing Guangcheng;Dou Linming;Wu Yun;Zhang Chengguo
褶皱带岩爆发生机制复杂，地应力重分布与构造的复杂程度密切相关。分析褶皱结构的地貌和煤层厚度的变化有助于识别容易发生岩爆的区域，从而提高煤矿的安全性和生产率。研究了西北地区4个矿井褶皱带煤层褶皱构造的分布特征。基于褶皱长宽比、肢间夹角、褶皱肢投影宽度与铰接区宽度比P1、曲率比P2、最大曲率和振幅等综合评价指标，分析煤层褶皱结构几何特征及煤厚变化。对4个煤矿的统计分析表明，褶皱长宽比由0.78变化到2.03，褶皱横截面最大曲率小于0.04。结构中褶皱截面曲率比不大于1.4，89%的褶皱截面肢间角大于150°。平缓褶皱构造占主导地位，具体地质形态为穹窿或盆地。煤矿上方煤层厚度等值线呈现出与煤层底板等高线类似的波动趋势。背斜区煤层厚度小于邻近向斜区煤层厚度。因此，矿区煤层厚度的整体变化很可能与区域主应力方向有关。
The mechanisms for rock bursts occurrences in fold zones are complex, and the redistribution of in-situ stresses is closely related to the complexity of the structures. Analysis of the geomorphology of fold structures and changes of coal thickness can help identify zones prone to rock bursts to improve safety and productivity in coal mines. This study investigated the distribution characteristics of fold structures in coal seams in fold zones in four mines in northwest China. Geometrical characteristics of fold structures in coal seams and changes of coal thickness were analysed, based on comprehensive evaluation indexes, such as the length–width ratio of folds, interlimb angle, ratioP1 of projected width of fold limbs to that of the hinge zone, curvature ratioP2, the maximum curvature and amplitude. The statistical analysis of the four coal mines shows that the length–width ratio of folds changed from 0.78 to 2.03 and the maximum curvature of cross sections of folds was less than 0.04. The curvature ratio of cross section of a fold in the structure was no more than 1.4 and the interlimb angles of cross sections of 89% of folds were larger than 150°. Gentle fold structures were dominant and the specific geological morphologies were domes or basins. The isopleth of coal thickness above the coal mines showed a fluctuation trend similar to the contour line of the floor of coal seams. The coal thickness in an anticline area was smaller than that in the neighboring syncline area. Therefore, the overall variation of coal thickness in the mining areas was likely to have a relation with the direction of the regional principal stress.