【作者】 倪含斌；

【导师】 张丽萍；

【作者基本信息】 浙江大学 ， 水资源利用与保护， 2009， 博士

【摘要】 水土流失是目前全球瞩目的环境问题之一。大规模资源集中开采和相应工程建设引起的人为加速水土流失问题是当前水土流失研究中的关键内容，已经引起各国政府部门和专家学者的广泛重视。本论文所选研究区——神府东胜矿区位于黄土高原风蚀水蚀交错带是典型的生态环境脆弱区，是全国重要的能源基地。随着煤炭资源开采，矿区的生态环境发生重大的改变，特别是扰动地表物质的堆积弃土与裸露基岩在当地特殊的气象水文条件下极易发生加速侵蚀，产生了一系列严重的环境问题。原本脆弱的生态环境变得更加脆弱，严重制约了矿区安全生产与可持续发展。本研究在对矿区1990年以来的整体环境进行广泛调查研究的基础上，基本了解了煤炭资源开采对于矿区带来的环境改变状况，并针对矿区物质组成与基岩分布的实际情况，利用模拟降雨技术、模拟风化试验技术，结合GIS技术，分别有选择性地对矿区原状未扰动坡地、不同堆积年限矿区弃土堆积物进行模拟降雨试验，选择裸露基岩(砒砂岩)进行室内模拟风化试验，并在矿区范围内选择包括了弃土堆积物、原状土、砒砂岩等矿区典型的地表物质组成的六道沟小流域进行矿区水土流失预测模型研究。通过本项目的研究，掌握弃土堆积物土壤自然恢复的规律可以为矿区水土流失治理和复垦研究提供新的方法和措施。一方面为神府东胜矿区水土流失治理提供技术支持，可以有效提高水土流失治理效率，另一方面为我国矿区水土流失治理研究提供理论依据，对矿区的可持续发展具有实际指导意义。本文的工作成果和主要结论如下：1)矿区开发导致地表剧烈扰动，地表物质经搬离而重新堆积，新堆积弃土石碴结构疏松，入渗率要明显高于原状土，达到稳定入渗时间要比原状土长，但一旦产流，则侵蚀非常严重。在高强度降雨时，土壤侵蚀加剧，较原状土有近10倍的增加，如果不采取必要措施，将会严重影响当地的生态环境。2)不同年限弃土具有明显不同的抗侵蚀能力；随着堆积年限的增加，弃土的植被覆盖和抗侵蚀能力都有较明显的提高；弃土年限超过7年的土壤植被和抗侵蚀能力有较好恢复，超过10年的堆积弃土基本达到原状土土壤环境水平。对于有效控制矿区扰动弃土的土壤侵蚀，主要在于提高其压实性，恢复其原来的结构特征，另外，增加植被覆盖度及加快其恢复速度也可以有效减少土壤侵蚀。3)存在生物结皮区径流量要大于同等降雨条件下的无生物结皮区，并且生物结皮覆盖度越大其径流产生量越大。存在生物结皮区的同期径流含沙量累计产沙量要比无生物结皮区要小。说明生物结皮具有很好的抗侵蚀作用。4)砒砂岩区的侵蚀产沙过程与岩石风化过程密切相关。在不考虑风蚀影响的情况下，影响砒砂岩风化速率的主要因素有岩性(矿物组成、孔隙特征、胶结物等)、处理条件、冻融周期等因素。不同岩性的砂岩在同样处理条件下具有不同风化速率。溶液浸泡可以减缓砒砂岩风化，在不同的冻融环境里其影响程度不尽相同。5)岩石的室内温控冻融风化模拟试验，风化速率远远小于实地的风化速率，这也间接证实在岩石的风化过程中，风或者其它因素的作用远远大于冻融作用；室内浸泡与无浸泡两种岩石风化试验结果也表明，在神府东胜煤矿区岩石的风化过程中风或其它因素的作用远远大于水的作用。6)通过野外降雨试验模拟发现矿区堆积弃土堆积物中新近弃土侵蚀剧烈，单场降雨侵蚀模数比类似原状土坡地的侵蚀模数增加10倍多，侵蚀产沙最大。在相同条件下，降雨强度越大，侵蚀模数越大。在风沙土坡地，一旦产生径流，则含沙量很大，且沟谷的形成过程为垂直渗流—坡地潜流—崩塌。模拟结果表明水土流失具有明显空间差异性，发现侵蚀最严重的地方主要是坡度为25度的沙黄土坡地。本文的主要创新点为：1)通过对矿区开发以来历年弃土堆积物进行设定雨强下的模拟降雨试验，获得了矿区土壤自破坏后堆积状态下进行自然恢复下的侵蚀产流产沙规律，为深入研究矿区开发以来扰动土壤水土流失动态发展趋势提供新的思路。2)在岩石风化试验研究中，分析研究手段方面，在总结当前研究现状的基础上，有了较大的突破和创新，一改过去采用单一的冻融分析、温度变化分析、化学过程分析的方法。首次提出了结合X衍射分析技术，根据当地环境的特征，采用冻融、温控和不同水化学环境相结合的风化模拟方法。通过不同的试验环境下岩石风化过程的比较分析，对定性、定量研究影响砒砂岩风化因素具有重要的科学意义。3)利用ArcGIS 8．3、Mapinfo 7．0等软件，结合生态学原理，将土壤侵蚀预测落实到生态地形单元上，经过对各种生态地形单元进行野外降雨试验，获得相应的侵蚀模数。经过对各生态单元内影响土壤侵蚀的各环境要素进行权重分析，应用组合数学原理进行整个小流域的水土流失预测预报。并通过在六道沟流域进行人工降雨模拟试验，模型得到证明。水土流失生态预报模型能够准确反映土壤水蚀的空间差异性。在坡度较陡，地形破碎，暴雨频发的黄土高原，此模型可以得到较好的应用。更多还原

【Abstract】 At present, soil and water loss has been widely concerned as one of the important environmental issues by the whole world. The accelerated soil and water loss induced by large-scale centralized exploitation and corresponding engineering construction, is the key research content of presently studies on soil erosion, which has been attracting extensive attention of many governments and experts. Shenfu-dongsheng coal mine area, be one of China’s important energy base, located in the combined wind and water erosion at northern Loess Plateau, is a typical area of fragile ecological environment. With the exploitation of coal resources, the environment there has been greatly changed, particularly because the accumulated spoil and exposed bedrock which disturb the rock soil easily resulted in accelerated erosion under the local special meteorological and hydrological conditions, and consequently a series of serious environmental problems occured. Fragile ecological environment has become more vulnerable, so it seriously constrained the mine area’s production safety and sustainable development.On the basis of an extensive investigation of the mine area’s overall environment under the development and construction since 1990, the authors mastered the mining area’s environmental changes due to the exploitation of coal resources. According to actual situations of mining material composition and bedrock’s distribution, using the simulated rainfall technology and the simulated weathering experimental technology, combined with GIS, simulated rainfall experiments were conducted respectively on the un-disturbed slopes and accumulated soils of different years, and Liudaogou watershed in this mine area was selected to study on soil erosion prediction model for all the mine area. This work supplies new methods and measures for a study of soil and water loss management and reclamation.On the one hand, this project, can provide technical support for the Shenfu Dongsheng mine to control soil erosion effectively, on the other hand, it also can offer a theoretical guidance on soil erosion for the sustainable development of mining areas of China.The main conclusions of the dissertation included: 1) The soils accumulated in different years had different anti-erosion capabilities, and with the increasing of accumulation time, the vegetation covering rate and anti-erosion ability were enhanced gradually.2) If the time of accumulated soils were over seven years, the vegetation and anti-erosion ability had well recovered, and if the time of accumulated soils were over ten years, the vegetation and anti-erosion ability had recovered to be similar to primary soil. And the effective measures to control soil erosion of disturbed spoil mainly on enhancing soil compactility and recovering original structure characteristics. Furthermore, increasement of vegetation coverage and rapide recovery rate can reduce soil erosion availably.3) Runoff in microbial crust district were greater than the same rainfall conditions without microbial crust. The sediment runoff of microbial crust was more than the same period of no microbial crust, and the test area of microbial coverage of 46% carried out least sediment runoff. Microbial crust of accumulated sediment yield was smaller than the one of non-microbial crust.4) Regardless of the effects of wind erosion, the main factors that affected the weathering rate of pisha-sandstones were the lithologies (mineralogical composition, pore characteristics, cementation,etc), treatment conditions, arrangement of drying -wetting-freezing cycle, etc.5) The indoor immersion and non-immersion weathering experiments also revealed that throughout the weathering process in the region, the role of wind was greater than the role of water.6) By simulating model of field rainfall erosion modulus in Liudaogou small watershed, we found that there is intense soil erosion occurred on late accumulated spoil with erosion modulus 10 times more than original slope and the largest sediment yield under field rainfall simulation. Under the same situation, the greater rainfall intensity is, the greater erosion modulus is. On sandy slope, once producing runoff, the sediment concentration would be large, and the formation process of gully is vertical seepage—slope undercurrent—landslip.The innovated progress of this dissertation included: 1) Through simulated rainfall experiments with different rainfall intensitis carried out on the accumulated soils since mine area’s exploitation, the rules of runoff and sediment erosion in the different accumulated soils of natural recovery have been obtained.This method improves our ideas to study on the soil and water erosion of disturbed soils since mine exploitation.2) On the foundation of summarization the current research, analysis methods of the rock weathering study have great breakthroughs and innovations. Instead of using a single analysis method, freeze-thaw analysis, temperature-change analysis, or chemical processes analysis, a new weathering simulation method was advanced, which is combined with X-ray, according to local environment features, and integrated with the cycle of freeze-thaw, temperature-change, and chemical processes.Through comparative analysis of rock weathering process under different environment, there’s a great scientific importance on qualitatively and quantitatively studying the factors affecting pisha-stones weathering.3) Based on the softwares of ArcGIS 8.3 and Mapinfo 7.0, combined with ecological principles, the objectives of this paper were to obtain erosion modulus by field rainfall experiments in various ecological terrain units, and to predict soil loss in the whole small watershed. According to watershed runoff concentration principle, combinatorics principle, and weights analysis of environmental factors, which affect soil erosion of each ecological unit, we constructed the soil erosion prediction model. Then by conducting rainfall simulation in Liudaogou small watershed, the model was proved. The soil erosion ecological prediction model can reflect the spatial difference of soil water erosion more accurately in the Loess plateau with steep slope, small terrain plot and frequent rainstorm.更多还原