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垃圾填埋场防渗墙墙体变形有限元计算及模拟试验研究

作者:润色论文网  来源:www.runselw.com  发布时间:2019/9/9 10:06:39  

摘要:在现代城市的发展过程中,垃圾的种类和数量日益繁多,对垃圾的处理也显得越来越重要。卫生填埋因其处理量大、技术成熟、易于实现的优点而被各国广泛采用。在垃圾填埋场的建造中,防渗处理是生活垃圾卫生填埋最重要组成部分之一,在垃圾填埋场天然防水能力不足的情况下,需要采用合适的防渗处理以防止垃圾渗滤液污染周围的环境。目前,以膨润土为主要材料建造的垂直防渗墙,具有工程造价低、易修复等特点,是垃圾填埋场防渗系统最普遍的采用方式。

垃圾填埋场防渗墙的使用环境较为复杂,不仅要承受垃圾填埋时产生的重力和周边土体引起的土压力,而且与外层覆盖土体存在相互作用;同时防渗墙对垃圾渗滤液还要有良好的的阻滞作用,防止垃圾渗滤液污染周围土壤及水资源。本文围绕垃圾填埋场防渗墙主要做了以下工作:

(1)阐述了垃圾填埋场的发展现状,对垃圾渗滤液的组成及可能造成危害进行了详细的介绍;概述了防渗墙的不同种类和其基本组成材料,对垃圾填埋场防渗墙力学性能及有限元分析的研究现状进行了总结。

(2) 对已有的聚乙烯醇改性防渗浆材进行基本性能的测试,介绍了浆材的基本组成成分,并对浆材的渗透性能、抗压性能、可灌性和吸附阻滞性进行了测量。

(3)合理的设计了防渗墙的室内模型,并从模型的设计、采用材料、测试原件以及具体的制备过程详细介绍了室内模型框架的搭建过程。并进行了防渗墙的浇筑和砂土的填筑,采用振弦式传感器和测斜仪收集模型数据。

(4)聚乙烯醇改性膨润土防渗墙水平位移随着墙体高度的增加而增大,比例近似呈线性关系。墙体极限应变值远小于浆材极限应变最大值,说明防渗墙是安全可靠的。防渗墙所受应力自墙底向上逐渐减小,墙体总体受力较小,未产生拉应力。

(5)聚乙烯醇改性膨润土防渗墙的弹性模量与周围土体较为接近,在实际使用中能有效的减少墙体裂缝的产生,防止渗滤液通过墙体裂缝污染周围的土壤及地下水。

In the process of the development of moderncities, the types and quantities of garbage are increasing, and the disposal ofgarbage is becoming more and more important. In the treatment of municipalsolid waste, sanitary landfill is widely used in many countries because of itsadvantages of large capacity, mature technology and easy realization. In theconstruction of landfills, anti-seepage treatment is one of the most importantcomponents of sanitary landfills. In the case of insufficient naturalwaterproofing capacity of landfills, appropriate anti-seepage treatment isneeded to prevent landfill leachate from polluting the surrounding environment.At present, the vertical cut-off wall constructed with bentonite as the mainmaterial has the characteristics of low cost and easy repair, which is the mostcommon way of landfill seepage control system.

The landfill cut-off wall is morecomplicated, for it not only needs to bear the gravity produced by landfill andsoil pressure caused by surrounding soil, but also needs to interact with theouter covering soil. Meanwhile, the cut-off wall also has a good blockingeffect on landfill leachate to prevent the landfill leachate from polluting thesurrounding soil and water resources. In this paper, the following work hasbeen done around the cut-off wall of landfill:

(1) This paper expounds the developmentstatus of landfill, introduces the composition of landfill leachate and itspossible hazards in detail, summarizes the different types of cut-off wall andits basic composition materials, and summarizes the research status of mechanicalproperties and finite element analysis of cut-off wall in landfill.

(2) The basic properties of the existingpolyvinyl alcohol modified anti-seepage slurry were tested. The basiccomposition of the slurry was introduced. The permeability, compressionresistance, grouting ability and adsorption retardation of the slurry weremeasured.

(3) The indoor model of the cut-off wall isdesigned reasonably, and the process of building the indoor model frame isintroduced in detail from the design of the model, the use of materials, thetesting of the original parts and the specific preparation process. Theanti-seepage wall and sand filling were carried out, and the model data werecollected by vibrating wire sensor and inclinometer.

(4) The horizontal displacement ofpolyvinyl alcohol modified bentonite cutoff wall increases with the increase ofwall height, and the proportion is approximately linear. The ultimate strain ofthe wall is far less than that of the grout, which shows that the cut-off wallis safe and reliable. The stress of the cut-off wall decreases gradually fromthe bottom to the top of the wall, and the overall stress of the wall is small,and there is no tensile stress. Because the elastic modulus of the wall is closeto that of the surrounding soil, the cracks in the wall can be reduced and theservice life of the wall can be prolonged in practical use.

(5) The polyvinyl alcohol modifiedbentonite cutoff wall is close to that of surrounding soil. It can effectivelyreduce the generation of wall cracks and prevent leachate from pollutingsurrounding soil and groundwater through wall cracks in practical use.

关键词:垃圾填埋场;防渗墙;模拟实验;应力应变;数值分析

Landfill; Cut-off Wall; SimulationExperiment; Stress and Strain; Numerical Analysi

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