陕北现代化煤炭开采区土地沙漠化影响及原因——以大柳塔—活鸡兔矿区为例

Impacts and Causes of Land Desertification in Modern Coal Mining Districts in the North of Shaanxi Province——a Case Study from Daliuta-Huojitu Mining District

为了弄清楚陕北现代化煤炭开采对沙漠与黄土交界处土地沙漠化和地质环境的影响,以神府煤田的大柳塔—活鸡兔矿区为例,采用遥感解译、大比例尺地面调查以及GIS技术,对矿区近20年来煤炭开采区沙漠化土地及地质环境的演化特征进行分析,探讨了土地沙漠化的影响因素。结果表明:近20年来研究区土地沙漠化总体呈好转趋势,1986—1996年是矿区沙漠化好转的主要时期,主要因为该时期煤炭开采规模较小,采空塌陷区增加缓慢;20世纪80年代中期以来,矿区因煤矿采空所形成的塌陷区面积不断扩大,但采空塌陷至少对严重和中度沙漠化土地的影响微弱;1996年以来,随着煤炭开采力度不断加大,采空塌陷区面积呈指数增长,但土地沙漠化仍处于一个相对稳定的时期;煤炭资源开发造成大面积地面塌陷和裂隙、地下水水位下降、泉水流量减少甚至干涸,以及地表径流减少等,会导致区域生物多样性的减少和湿地植被的演替,使生态环境更加脆弱。因此,影响矿区土地沙漠化的主要因素是气候变化和其他人为因素,而不是矿区生态特征和采空塌陷因素。设立重要的生态环境和水资源保护区是保护有限的水资源和生物资源必要手段,也是减轻土地沙漠化的重要途径。

In order to make up the impacts of modern coal mining on land desertification and geologic environment at the junction of desert and loess in the north of Shaanxi Province,based on remote sensing interpretation,GIS and field investigation on large scale,taking Daliuta-Huojitu mining district of Shenfu Coalfield as an example,evolution characteristics of land desertification and geologic environment of coal mining district in the last 20 years were analyzed,influencing factor of land desertification was discussed.The results showed that land desertification was on a decreasing tendency during the last 20 years,the main period of land desertification decreasing was from 1986 to 1996,the main reason was that scale of coal mining was small in the period and the subsided area increased slowly;since the 1980s,the subsided area caused by coal mining in the district was keeping expanding,but the subsided area had little influence on serious and moderate land desertification at least;since 1996,although the coal mining increased continuously,the subsided area increased exponentially,but land desertification kept relative stable;coal exploitation caused large surface collapse and fissure,water table depression,discharge of spring decreased（even dried）,surface runoff decreased,and so on.Therefore,the main factors influencing land desertification in the mining district were climate change and others,not ecological characteristics and mining collapse.The effective mean is to build ecological environment and water resources conservation district,which also improves land desertification.