煤矿开采沉陷地裂缝对植被覆盖的影响

Impacts of Ground Subsidence and Fissures Caused by Coal Mining on Vegetation Coverage

浅埋煤层开采引起地表出现大量地裂缝,部分地裂缝自我修复后闭合程度较好,但大部分地裂缝难以闭合而发展成为永久裂缝。在进行生态重建工作时,地裂缝及其周边植被状况关系到矿区生态重建的效果。以大柳塔矿区2003、2004和2005年开采的工作面为例,利用现场勘测和内业统计分析方法,首先结合井下开采布置图对地裂缝的空间分布进行分析,然后利用Arc GIS 10.0软件提取地裂缝及其周边植被信息,统计分析地裂缝周边植被指数均值变化情况。研究发现,地裂缝主要分布在开切眼、停采线、工作面相邻处以及巷道交叉处,且地裂缝数随地形起伏增大而增多;通过对192条地裂缝的统计回归分析发现,距地裂缝2 m范围内的植被与地裂缝显著相关(R2≥0.96,P<0.05),而>2 m范围的植被与地裂缝相关性未达显著水平(P>0.05),表明受到其他因子的影响较大;随机选取7条地裂缝,分析距地裂缝不同距离处植被指数均值变化情况,发现地裂缝对距其4 m范围内植被有影响。

Mining of shallow coal seams mining may cause formation of lots of fissures, some of which close automatically,while the others hardly close and then develop into permanent fissures. In ecological reconstruction, ground fissures andtheir surrounding vegetation covers is somewhat related to the effect of ecological reconstruction of the mining area. Theworking faces opened up in 2003, 2004 and 2005 in the Daliuta mining area were selected as examples for field investigation and statistical analysis of fissures. Firstly, based on the layouts of underground mining, distribution of permanent fissures was analyzed; basic information of permanent fissures and their surrounding vegetation covers was extracted with theaid of the ArcGIS 10 0 software; and then statistic analysis was performed of variation of the vegetation covers around thefissures. It was found that fissures were mainly distributed at openoff cuts, stopping lines, bordering of two working facesand intersection of tunnels, and the number of fissures rose with rising undulation degree of the terrain. Statistic regressionanalysis of 192 ground fissures shows that the vegetation 2 m away from permanent fissures is significantly and closely related to the fissures （P〈0 05）, while the vegetation 〉2 m away from fissures is not so much related （P〉0 05）, which indicates that the vegetation along the fissures is highly affected by other factors. Analysis of seven randomly selected permanent fissures shows that the fissures have some impact on the vegetation within 4 m alongside them.