平朔矿区及其周边沟谷系统30年演变特征

发布时间：2018-10-25 08:49

【摘要】：沟谷地貌作为黄土高原上广泛分布的基本地貌类型,既兼具一定的生态功能,也可引发土壤侵蚀恶性循环,分析矿区周围的沟谷地貌特征及其影响,对提高土地复垦与生态修复的工程效果具有重要意义。本文以平朔矿区及其周边的沟谷系统为研究对象,提取沟谷线的形态、地貌特征,讨论各地类中沟谷的坡度变化与沟道侵蚀相互作用,分析平朔矿区周围沟谷系统的时空演变。主要研究结论如下:(1)量化了沟谷形态特征。选取沟谷线高差、坡降等形态特征指标,分析研究区内沟谷形态特征的变化后发现,小于5km的沟谷变化频繁,沟谷长度与数量呈总体增加趋势。研究区内大部分沟谷线高差在0-100m之间,负高差沟谷线长度与数量增加。沟谷线的坡降平均值总体降低,沟谷线沟头处坡降较高,土壤侵蚀量大。沟谷的宽深比随发育时间的累积而增加,沟谷主要由切沟、冲沟、坳沟组成。(2)统计了排土场区、露天矿区、井工矿区、工业场地、原地貌沟谷周围的坡度特征。自然状态下的沟谷地貌以5°-10°的微陡地势为主。露天矿区、井工矿区、工业场地、排土场区的坡度主要集中于0°-10°之间,极陡地形持续增加。矿坑工作帮边坡与内排土场边坡坡度大于15°,外排土场边坡坡度在20°-35°之间。堆状排土法塑造出的外排土场以小于10°的平坦、微陡地形为主,工业场地区地势较低,沟谷线多分布于此。(3)分析了采矿扰动后的沟谷地貌时空变化。1986至2013年平朔及周围地区沟谷系统的流域面积主要影响因素是露天矿坑与排土场,沟谷因矿坑延长,沟道因排土场而缩短。沟谷线呈现单线异向和单线相向的汇流特征,矿坑平台处出现平行沟谷线。(4)明确了沟谷系统的组成特点与生态效应。平朔矿区及其周围地区沟谷系统由细沟、浅沟、切沟、冲沟、坳沟组成。其中,细沟、浅沟以及切沟的土壤侵蚀量大,多不利影响,而冲沟、坳沟内存在多样化的生镜,具有提高生物多样性的生态效应。
[Abstract]:As a basic geomorphic type widely distributed on the Loess Plateau, gully geomorphology can not only have certain ecological functions, but also cause a vicious circle of soil erosion. The characteristics and effects of gully geomorphology around the mining area are analyzed. It is of great significance to improve the engineering effect of land reclamation and ecological restoration. This paper takes the gully system of Pingshuo mining area and its surrounding area as the research object, extracts the shape and geomorphological characteristics of the gully line, discusses the interaction between the slope change of the gully and the channel erosion in various areas, and analyzes the space-time evolution of the gully system around the Pingshuo mining area. The main conclusions are as follows: (1) the morphological characteristics of the valley are quantified. After analyzing the variation of the morphological characteristics of the valley in the study area, it was found that the valley with less than 5km changed frequently, and the length and quantity of the gully showed a general increasing trend. The height difference of most valley lines in the study area ranges from 0 to 100 m, and the length and number of negative valley lines increase. The average slope gradient of the valley line was decreased generally, and the slope at the gully line head was higher, and the soil erosion was larger than that at the end of the gully line. The width-depth ratio of the gully increases with the accumulation of development time. The gully is mainly composed of cutting trench, gully and depression. (2) the slope characteristics of dump area, open-pit area, well industry area, industrial site and original geomorphologic gully are analyzed. The gully landforms in the natural state are mainly slightly steep terrain of 5 掳- 10 掳. The slope of opencast mine area, well mining area, industrial site and dump area is mainly between 0 掳-10 掳, and the extremely steep terrain continues to increase. The slope of the working side slope of the pit and the slope of the internal dump slope is more than 15 掳, and the slope of the external dump slope is between 20 掳-35 掳. The external dump shaped by the pile drainage method is flat with less than 10 掳, slightly steep terrain, and low topography in the industrial area. (3) the temporal and spatial variation of gully geomorphology after mining disturbance is analyzed. The main influencing factors of valley area in Pingshuo and surrounding areas from 1986 to 2013 are opencast pit and dump. The ditch was shortened by the dump. The trench line presents the confluence characteristics of unidirectional and single-line opposite direction, and the parallel valley line appears at the platform of mine pit. (4) the composition characteristics and ecological effect of the gully system are clarified. The gully system of Pingshuo mining area and its surrounding area is composed of fine gully, shallow gully, cutting ditch, gully and depression. Among them, the amount of soil erosion in gully, shallow ditch and cut ditch is large, and there are many adverse effects on soil erosion. However, there is a variety of mirror in gully and depression, which has the ecological effect of improving biodiversity.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD15;TD88
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本文编号：2293211