干湿循环条件下垃圾填埋场毛细阻滞式覆盖层研究
发布时间：2018-12-24 11:41
【摘要】：垃圾填埋场终场覆盖层的主要功能为减小降雨入渗，但传统的覆盖层有粘土开裂、容易滑坡失稳、工程造价高等缺点，毛细阻滞式覆盖层做为一种新型的终场覆盖层，由粗细粒两层土组成，避免了上述缺点，因此，成为了目前的一个研究热点。 本文通过土柱试验和数值模拟两种方法研究了毛细阻滞式覆盖层。论文首先模拟了湿润地区、半湿润地区、干旱地区一个月干湿循环条件下的毛细阻滞式覆盖层，通对模拟结果的孔隙水压力、体积含水量、截面渗流量等参数进行分析，得到在考虑了干湿循环条件覆盖层毛细阻滞的效果评价，并通过数值模拟为后续的土柱试验提供参数；第三章通过土柱试验来验证数值模型，通过对试验结果的分析，得到干湿循环作用下覆盖层效果评价的一些初步结论；第四章再通过数值模拟的方法，模拟一年干湿循环条件下毛细阻滞覆盖系统，分析了不同材料厚度、不同地区、不同坡度和植物对毛细阻滞覆盖层性能的影响，并最终给出毛细阻滞式覆盖层的整体性能的综合效果评价。研究结果表明： 土柱模型粗粒土和细粒土之间的毛细阻滞效果明显，底部渗水量也能反映出这种效果。得出了不同气候边界条件下覆盖层的毛细突破时间。湿润地区的毛细突破时间最早，但半湿润地区的渗漏量却最大。 通过三组粉土与砂土组合的土柱试验，首先验证了数值模型的合理性，两者的结论基本相符，土柱试验过程中，细粒土含水量远大于粗粒土，毛细阻滞效果明显。湿润地区土柱共发生两次渗漏，5#点也发生了两次毛细突破，分析显示，暴雨导致了毛细突破和渗漏的发生。 通过数值模拟的方法研究了一年干湿循环条件下覆盖层的水量平衡状况，以广州为代表的湿润地区如果达到渗漏量为零的要求，所需的细粒土厚度为1.3m，，粗粒土厚度0.3m，同时，覆盖层中需要种植相应的植物以增大腾发量。在覆盖层的设计中，细粒土的厚度对渗漏量的影响最大，坡度次之，粗粒土的厚度影响最小。覆盖层细粒土的侧向导排量随着坡度的增大而增大，导排量的增大使得水分更多的排出土体，从而减小了渗漏量。以北京为代表的半湿润地区如果达到渗漏量为零的要求，所需的细粒土厚度为0.8m，粗粒土厚度0.3m。
[Abstract]:The main function of the landfill terminal overburden is to reduce rainfall infiltration, but the traditional overburden has the disadvantages of clay cracking, easy landslide instability, high engineering cost, etc. As a new type of terminal overburden, the capillary block overburden is a new type of terminal overburden. It is composed of coarse and fine-grained two-layer soil, which avoids the above disadvantages, so it has become a hot research topic at present. In this paper, capillary block overburden is studied by means of soil column test and numerical simulation. In this paper, the capillary block overburden in humid, semi-humid and arid areas for one month is simulated. The parameters of pore water pressure, volume water content and cross-section seepage flow of the simulated results are analyzed. The effect evaluation of capillary block of overburden considering dry and wet circulation conditions is obtained, and the parameters for subsequent soil column test are provided by numerical simulation. In the third chapter, the numerical model is verified by soil column test. By analyzing the test results, some preliminary conclusions on the effect evaluation of the overburden under the action of dry-wet cycle are obtained. In chapter 4, the capillary block covering system under dry and wet cycle for one year is simulated by numerical simulation. The effects of different material thickness, different region, different slope and plant on the performance of capillary block covering are analyzed. Finally, the comprehensive performance evaluation of capillary block coating is given. The results show that the capillary block effect between coarse grained soil and fine grained soil in the soil column model is obvious, and the water leakage at the bottom can also reflect this effect. The capillary breakthrough time of the overburden under different climatic boundary conditions is obtained. The capillary breakthrough time is the earliest in the humid area, but the leakage is the largest in the sub-humid area. Through three groups of silt and sandy soil combination soil column test, the rationality of the numerical model is verified at first. The conclusion of the two models is basically consistent. During the soil column test, the moisture content of fine grained soil is much larger than that of coarse grained soil, and the capillary block effect is obvious. Soil column leakage occurred twice and capillary breakthrough occurred twice in humid area. The analysis showed that the rainstorm resulted in capillary breakthrough and leakage. The water balance of overburden under dry and wet cycle is studied by numerical simulation. The thickness of fine grained soil is 1.3 m if the wet area in Guangzhou reaches the requirement of zero leakage. The thickness of coarse-grained soil is 0.3m. at the same time, the corresponding plants should be planted in the overburden to increase the evapotranspiration. In the design of overburden, the thickness of fine grained soil has the greatest influence on the leakage, followed by the slope, and the thickness of coarse grained soil is the least. The lateral guide displacement of the fine grained soil increases with the increase of the slope, and the increase of the conductance causes more water to be discharged from the soil, thus reducing the leakage. In the sub-humid area represented by Beijing, if the leakage is zero, the thickness of fine soil is 0.8m, and the thickness of coarse grained soil is 0.3m.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU411
[Abstract]:The main function of the landfill terminal overburden is to reduce rainfall infiltration, but the traditional overburden has the disadvantages of clay cracking, easy landslide instability, high engineering cost, etc. As a new type of terminal overburden, the capillary block overburden is a new type of terminal overburden. It is composed of coarse and fine-grained two-layer soil, which avoids the above disadvantages, so it has become a hot research topic at present. In this paper, capillary block overburden is studied by means of soil column test and numerical simulation. In this paper, the capillary block overburden in humid, semi-humid and arid areas for one month is simulated. The parameters of pore water pressure, volume water content and cross-section seepage flow of the simulated results are analyzed. The effect evaluation of capillary block of overburden considering dry and wet circulation conditions is obtained, and the parameters for subsequent soil column test are provided by numerical simulation. In the third chapter, the numerical model is verified by soil column test. By analyzing the test results, some preliminary conclusions on the effect evaluation of the overburden under the action of dry-wet cycle are obtained. In chapter 4, the capillary block covering system under dry and wet cycle for one year is simulated by numerical simulation. The effects of different material thickness, different region, different slope and plant on the performance of capillary block covering are analyzed. Finally, the comprehensive performance evaluation of capillary block coating is given. The results show that the capillary block effect between coarse grained soil and fine grained soil in the soil column model is obvious, and the water leakage at the bottom can also reflect this effect. The capillary breakthrough time of the overburden under different climatic boundary conditions is obtained. The capillary breakthrough time is the earliest in the humid area, but the leakage is the largest in the sub-humid area. Through three groups of silt and sandy soil combination soil column test, the rationality of the numerical model is verified at first. The conclusion of the two models is basically consistent. During the soil column test, the moisture content of fine grained soil is much larger than that of coarse grained soil, and the capillary block effect is obvious. Soil column leakage occurred twice and capillary breakthrough occurred twice in humid area. The analysis showed that the rainstorm resulted in capillary breakthrough and leakage. The water balance of overburden under dry and wet cycle is studied by numerical simulation. The thickness of fine grained soil is 1.3 m if the wet area in Guangzhou reaches the requirement of zero leakage. The thickness of coarse-grained soil is 0.3m. at the same time, the corresponding plants should be planted in the overburden to increase the evapotranspiration. In the design of overburden, the thickness of fine grained soil has the greatest influence on the leakage, followed by the slope, and the thickness of coarse grained soil is the least. The lateral guide displacement of the fine grained soil increases with the increase of the slope, and the increase of the conductance causes more water to be discharged from the soil, thus reducing the leakage. In the sub-humid area represented by Beijing, if the leakage is zero, the thickness of fine soil is 0.8m, and the thickness of coarse grained soil is 0.3m.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU411
【相似文献】
相关期刊论文 前10条
1 З.A.诺索娃,李国X
本文编号：2390574
本文链接：https://www.wllwen.com/guanlilunwen/chengjian/2390574.html
