填埋场斜坡上土工膜受力特性离心模型试验研究

发布时间：2018-05-27 19:33

本文选题：填埋场 + 土工膜　；参考：《浙江大学》2013年硕士论文

【摘要】：随着我国城市化水平的提高,城市固体废弃物的产量急剧增加。由于所处环境复杂,填埋场衬垫系统的安全性受到很大挑战。填埋场斜坡上的衬垫系统在垃圾土的拖拽等作用下,锚固端将受到很大的拉力,当拉力超过衬垫材料的抗拉强度时,衬垫系统将发生破损,严重威胁填埋场周围的环境安全。因此,研究填埋场衬垫系统受力状况,计算衬垫材料受力大小,优化衬垫系统结构型式,对填埋场的安全运行和维护周围居民的生命财产安全具有重要意义。由于衬垫系统组成复杂,直接研究有很大难度,本文以衬垫系统中最重要的组成——土工膜为研究对象,从单层衬垫入手对衬垫系统的受力状况进行研究。在对试验相似率进行认识的基础上,配置了符合中国垃圾土特性并且能够用于离心模型试验的模型垃圾土,加工了模型土工膜和相应的试验装置。共进行了6组离心模型试验,前四组主要研究了斜坡坡度、界面强度型式和垃圾土压缩性对土工膜的受力状况的影响,结果表明：斜坡上土工膜存在中性点,以中性点为界土工膜可分为受拉区和受压区；坡度和沉降是影响土工膜拉力发展的重要因素,坡度或沉降越大,拉力越大；当土工膜上表面光滑下表面粗糙时,外部作用力很难向土工膜下界面传递,土工膜锚固端拉力几乎为零。后两组试验重点研究了导排层和土工膜所在单元的位置对土工膜受力状况的影响,结果表明：导排层的存在能够极大的减小土工膜的拉力；单元的位置不同,单元所处的应力状态不同,土工膜的受力状态有很大差别。结合试验结果,建立FLAC分析模型,对试验工况和影响土工膜受状况的因素进行了深入分析。结果表明：FLAC模拟结果和试验结果很好的吻合；沉降是通过改变界面强度的发挥程度来影响土工膜拉力的发展；导排层的存在极大的降低了土工膜端部的拉力,但当导排层厚度大于0时,导排层厚度对土工膜拉力影响较小；对多层单元的填埋场来说,中部单元的土工膜所受的拉力最大,处于最危险的状态；锚固平台的存在极大的改善了土工膜的受力状态,使其端部拉力减小最后,根据试验得到的规律对传统的极限平衡法进行了修正,计算结果与试验结果吻合的比较好,并以深圳下坪填埋场为例进行了应用分析。
[Abstract]:With the development of urbanization in China, the output of municipal solid waste increases rapidly. Because of the complex environment, the security of the landfill liner system is challenged. The anchoring end of the landfill slope will be subjected to a lot of tensile force under the action of garbage towing. When the tensile force exceeds the tensile strength of the liner material, the liner system will be damaged, which will seriously threaten the environmental safety of the landfill site. Therefore, it is of great significance for the safe operation of the landfill and the maintenance of the life and property of the surrounding residents to study the stress condition of the gasket system of the landfill, to calculate the force of the gasket material and to optimize the structure of the gasket system. Due to the complexity of the gasket system, it is very difficult to study it directly. In this paper, the geomembrane, the most important component of the liner system, is taken as the research object, and the mechanical condition of the liner system is studied from the single layer liner. On the basis of understanding the similarity rate of the test, the model waste soil which conforms to the characteristics of Chinese refuse soil and can be used in centrifuge model test is configured, and the model geomembrane and the corresponding test equipment are processed. Six groups of centrifugal model tests were carried out. The first four groups mainly studied the influence of slope gradient, interface strength type and garbage soil compressibility on the stress state of the geomembrane. The results showed that there were neutral points in the geomembrane on the slope. The geomembrane with neutral point as the boundary can be divided into tensile zone and compression zone, the slope and settlement are the important factors affecting the development of geomembrane tension, the larger the slope or settlement, the greater the tensile force; when the upper surface of the geomembrane is smooth and the lower surface is rough, The external force is difficult to transfer to the interface under the geomembrane, and the tensile force at the Anchorage end of the geomembrane is almost zero. The last two groups of experiments focused on the influence of the location of the guiding layer and the element of the geomembrane on the stress state of the geomembrane. The results showed that the existence of the guiding layer could greatly reduce the tensile force of the geomembrane, and the location of the element was different. The stress state of the element is different, the stress state of the geomembrane is very different. Combined with the test results, the FLAC analysis model was established, and the experimental conditions and the factors affecting the geomembrane acceptance were deeply analyzed. The results show that the results of the FLAC simulation are in good agreement with the experimental results; the settlement affects the development of the geomembrane tensile force by changing the exertion degree of the interface strength; the existence of the guide layer greatly reduces the tensile force at the end of the geomembrane. However, when the thickness of the guide layer is greater than 0, the thickness of the guide layer has little effect on the geomembrane tension, and the geomembrane of the central unit is in the most dangerous state for the landfill site with multi-layer units. The existence of Anchorage platform greatly improves the stress state of the geomembrane and reduces the tensile force at the end of the Anchorage platform. Finally, the traditional limit equilibrium method is modified according to the law obtained from the test. The calculated results are in good agreement with the test results, and the application analysis of Xiaping landfill in Shenzhen is carried out.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU43

【引证文献】