非饱和土柱试验装置开发及毛细阻滞型防渗层参数试验研究

发布时间：2018-06-22 15:04

本文选题：毛细阻滞 + 封场覆盖　；参考：《北京交通大学》2017年硕士论文

【摘要】：毛细阻滞型覆盖层是一种新型的垃圾填埋场封场覆盖形式,其防渗机理,计算模型,设计参数都有待进一步的研究。本论文为研究毛细阻滞型覆盖层的渗透行为,研发了常规毛细阻滞型覆盖层土柱试验装置和带抽吸作用的土柱试验装置。采用新研发的土柱试验装置进行了均匀土柱,毛细阻滞型土柱,抽吸作用土柱的降雨入渗试验,试验结果表明:(1)新研发的常规毛细阻滞型覆盖层土柱试验装置和带抽吸作用的土柱试验装置设计合理,工作状态良好,能够满足毛细阻滞型覆盖层的渗透行为研究的需要;(2)改进了湿润锋前进法。发现肉眼可观测的湿润锋并不是湿润锋前进法使用的必要条件,通过传感器识别湿润锋是可行的,并且计算精度满足非饱和渗透系数测量的要求。这一改进突破了原有湿润锋前进法中依赖肉眼观测湿润锋的局限性,大大拓展了这一方法的适用范围,并且更加的方便准确;(3)毛细阻滞型覆盖层的击穿时间和毛细阻滞覆盖层细粒土厚度、细粒土初始含水率、降雨强度等有关,且分别呈线性正相关、线性负相关、幂函数负相关关系;(4)基于试验数据,建立了一个简化的毛细阻滞型覆盖层细粒土层储水能力及界面击穿时间的计算模型,该模型计算结果和试验结果一致;(5)基于毛细阻滞覆盖层细粒土层的储水能力及界面击穿时间计算模型,提出了垃圾填埋场毛细阻滞覆盖层细粒土层的设计原则,并针对湿润地区、半湿润地区、干旱地区、半干旱地区的4个代表性案例,给出的了具体的参数设计;(6)初步进行了带抽吸层与不带抽吸层的毛细阻滞土柱的对比试验,证明在毛细阻滞土柱粗粒土层侧面加细粒土层,能起到引流效果,起到延缓击穿时间的作用。
[Abstract]:Capillary barrier overlay is a new type of landfill seal covering. Its seepage prevention mechanism, calculation model and design parameters need to be further studied. In order to study the permeation behavior of capillary retarded overburden, the conventional capillary block soil column test device and the soil column test device with suction action were developed in this paper. The rainfall infiltration test of homogeneous soil column, capillary block soil column and suction soil column was carried out with the newly developed soil column test device. The experimental results show that: (1) the newly developed conventional capillary-block soil column test device and the soil column test device with suction action are reasonably designed and in good working condition. It can meet the needs of the study of permeability behavior of capillary block overlay. (2) the wetting front advance method is improved. It is found that the observable wetting front with the naked eye is not a necessary condition for the wetting front forward method. It is feasible to identify the wetting front by the sensor, and the accuracy of calculation can meet the requirements of unsaturated permeability coefficient measurement. This improvement breaks through the limitation of the former wet front forward method which relies on the naked eye to observe the wetting front, and greatly expands the scope of application of this method. And more convenient and accurate. (3) the breakdown time of capillary block cover is related to the thickness of fine soil, initial moisture content of fine soil, rainfall intensity and so on, and is linear positive correlation, linear negative correlation, respectively. (4) based on the experimental data, a simplified model for calculating the water storage capacity and interfacial breakdown time of fine grained soil layer of capillary retarded layer is established. The calculated results of the model are consistent with the experimental results. (5) based on the calculation model of water storage capacity and interface breakdown time of capillary retarded fine soil layer, the design principle of capillary blocking fine soil layer of landfill site is put forward. According to the four typical cases of humid, semi-humid, arid and semi-arid areas, the specific parameter design is given. (6) the comparative test of capillary block soil column with and without suction layer is carried out. It is proved that adding fine soil layer to the side of coarse soil layer of capillary block soil column can play a drainage effect and delay the breakdown time.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU41

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