Geological model of water preserved mining in Karst mountain areas in southwest China
LI Tao1,2 ,GAO Ying1,2 ,AI Dechun1,2 ,YANG Junwei1,2
我国西南地区煤炭储量丰富,但岩溶山区条件下石漠化十分严重,特别是煤炭开采进一步促进了石漠化进程。为协调我国西南地区煤炭开采与生态环境保护的矛盾,开展西南岩溶山区保水采煤地质模式研究。以六盘水煤田,特别是发耳矿区米箩煤矿为研究背景,基于地质调查、采掘揭露、矿井水文观测、地下水钻孔显微高速摄像观测等手段的成果,剖析了研究区生态、采煤、构造及水文条件,研究了西南岩溶山区的煤-水组合关系特征,阐释了岩溶山区煤炭开采驱动石漠化的过程;进而采用统计分析、三轴卸载实验、水-电相似模拟研究了西南地区导水裂隙带发育高度、整体下沉带内相对隔水岩体采动渗透性变化及采煤侧向渗流下生态水位响应规律。研究结果表明:西南岩溶山区煤炭开采导致生态潜水位下降促使水土流失增加,进而驱动西南岩溶山区石漠化进展,是该区保水采煤的关键。研究区煤炭开采厚度小(1~3m),上覆基岩厚度大(800~1 000m),导水裂隙带发育有限,导水裂隙带以上相对隔水岩层卸载后仍能有效隔水,采煤后垂向渗流微弱。但采煤沟通的基岩含水层与生态潜水存在侧向补给渗流,煤-水关系为侧向渗流型。研究区典型采矿地质条件下,煤柱留设80m可实现保水采煤,而超前注浆可减少保水煤柱留设。本研究可以为西南岩溶山区采煤规划提供借鉴。
There are a lot of coal resource in southwest China, where rocky desertification is very serious in Karst mountainous areas,especially in coal mining areas,which further promotes the process of rocky desertification. In order to coordinate the contradiction between coal mining and ecological environment protection in southwest China,the geo-logical model of water preserved mining in Karst mountainous area of southwest China was studied. Taking Liupanshui coal field,especially Miluo Coal Mine of Fa’er Mining Area,as an example,the characteristics of “coal” and “water” in the southwest Karst mountain areas had been studied based on the analysis of the ecological,coal mining,tectonic geology and hydrological conditions in the study area using geological survey,mining exposure,mine hydrological ob-servation,and groundwater borehole microscopic high-speed video obser-vation methods. The process of rocky desertification driven by coal mining in Karst mountain areas had explained. Then,the statistical analysis,three axis unloading experiment and water-electric similar simulation had been used to study the development height of the water conduc-ting fissure zone in southwest China,the change of the rock mass in the whole subsidence zone and the response law of the ecological water level under the lateral seepage of the coal mining. The result shows that the coal mining in south-west Karst area leads to the decline of diving position,which promotes soil and water loss,and drives the progress of rocky desertification in Karst mountainous area in southwest China. This is the key problem of water preserved mining in this area. In the study area,the thickness of coal mining in the study area is small at 1 ~ 3 m,and the thickness of overlying bedrock is large at 800 ~ 1 000 m. The development of water conducting fissure zone is limited,and the per-formance of the aquifers is fine. The vertical seepage flow is weak,but the coal aquifers and the eco-phreatic exist lat-eral seepage,and the relationship of “coal” and “water” is the lateral seepage type. Under the typical mining geolog-ical conditions in the study area,a lateral coal pillar with a width of 80 m can be achieved,and the advance grouting can reduce the retention of water retaining pillars. This study can provide a basis for mining planning in Karst moun-tainous areas of southwest China.
water-preserved coal mining;karst;rocky desertification;coal pillar
主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会