垃圾填埋场裂隙衬垫材料防渗性能研究

发布时间：2018-10-29 08:20

【摘要】：填埋法是包括我国在内的世界上大多数国家普遍采用的垃圾处置方法，与其他垃圾处置方法相比，其具有处理垃圾数量大、方便易行等优点。但这种方法也存在着许多二次污染问题,比如填埋气和渗滤液等。如不妥善处理，将会对附近地区，尤其是地下水造成污染。如何采取有效措施防止垃圾填埋的二次污染，是亟待解决的重要课题。衬垫系统是垃圾填埋场的重要组成部分，但衬垫在外界环境影响下出现裂隙。裂隙对衬垫的防渗性能有着重要的影响，必须对其进行系统深入地研究才能保证衬垫的可靠性和有效性。研究受渗滤液影响下裂隙衬垫的防渗性能，对于防止垃圾填埋场对周围环境的污染具有重要的社会意义和应用价值。本文采用室内实验、理论分析等方法，对土体在干湿循环条件下裂隙的产生和发展、渗滤液作用对裂隙衬垫防渗性能的影响等进行了初步的探讨。本文的研究内容主要包括：（1）采用室内模拟试验方法，研究压实黏土在多次干湿循环作用下，裂隙的演化规律。将裂隙图像进行矢量化处理后，通过计算得出裂隙相关参数。从脱湿过程与再次水化过程两方面得到了压实黏土裂隙开展机理及变化规律。（2）探讨溶液及不同膨润土含量对黏土界限含水率的影响。对不同膨润土含量的黏土在不同溶液作用下的界限含水率进行研究，加深了膨润土含量、孔隙溶液等因素对黏土界限含水率影响规律的认识，初步探明了渗滤液与土的相互作用机理。（3）采用室内渗透实验方法，研究裂隙对压实黏土衬垫渗透性能的影响。以去气自来水和垃圾填埋场渗滤液中代表性污染物为模拟渗滤液，采用变水头试验测量无裂隙以及出现裂隙后土样的饱和渗透系数，，并进行对比分析。（4）将衬垫划分为裂隙部分和非裂隙部分，通过污染物运移的对流弥散方程的计算，探讨不同衬垫厚度情况下裂隙扩展深度、裂隙层和下覆层渗透系数对污染物运移的影响。
[Abstract]:Landfill method is a kind of waste disposal method which is widely used in most countries in the world including our country. Compared with other waste disposal methods, it has the advantages of large amount of garbage treatment, convenient and easy to carry out and so on. However, there are many secondary pollution problems in this method, such as landfill gas and leachate. If not properly treated, it will cause pollution to nearby areas, especially groundwater. How to take effective measures to prevent secondary pollution of landfill is an important subject to be solved. The liner system is an important part of the landfill site, but cracks appear in the gasket under the influence of the external environment. The crack has an important influence on the impermeability of the liner, and it must be studied systematically and deeply to ensure the reliability and effectiveness of the liner. It is of great social significance and application value to study the anti-seepage performance of the fissure liner under the influence of leachate to prevent the pollution of the surrounding environment in the landfill site. In this paper, laboratory experiments, theoretical analysis and other methods are used to discuss the formation and development of cracks in soil under dry and wet circulation and the influence of leachate on the impermeability of fissure liners. The main contents of this paper are as follows: (1) the evolution of cracks in compacted clay under dry and wet cycles is studied by laboratory simulation test. After vectorizing the fracture image, the fracture related parameters are calculated. The mechanism and variation of compacted clay fissures were obtained from the dehumidification process and rehydration process. (2) the effect of solution and bentonite content on the limit moisture content of clay is discussed. The limit water content of clay with different bentonite content under the action of different solution was studied. The effect of bentonite content, pore solution and other factors on the limit water content of clay was studied. The mechanism of interaction between leachate and soil was preliminarily investigated. (3) the influence of cracks on permeability of compacted clay liner was studied by laboratory permeation experiment. Taking the representative pollutants in the leachate of the degassing tap water and landfill as the simulated leachate, the saturated permeability coefficient of the soil samples without fissures and after the fissures were measured by the water head test, and the results were compared and analyzed. (4) the gasket is divided into fissures and non-fissures. By calculating the convection dispersion equation of pollutant transport, the influence of crack propagation depth, permeability coefficient of fissure layer and lower layer on pollutant transport under different thickness of liner is discussed.
【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU993.3;TU411.4

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