【摘要】：垃圾填埋場(chǎng)終場(chǎng)覆蓋層的主要功能為減小降雨入滲，但傳統(tǒng)的覆蓋層有粘土開(kāi)裂、容易滑坡失穩(wěn)、工程造價(jià)高等缺點(diǎn)，毛細(xì)阻滯式覆蓋層做為一種新型的終場(chǎng)覆蓋層，由粗細(xì)粒兩層土組成，避免了上述缺點(diǎn)，因此，成為了目前的一個(gè)研究熱點(diǎn)。 本文通過(guò)土柱試驗(yàn)和數(shù)值模擬兩種方法研究了毛細(xì)阻滯式覆蓋層。論文首先模擬了濕潤(rùn)地區(qū)、半濕潤(rùn)地區(qū)、干旱地區(qū)一個(gè)月干濕循環(huán)條件下的毛細(xì)阻滯式覆蓋層，通對(duì)模擬結(jié)果的孔隙水壓力、體積含水量、截面滲流量等參數(shù)進(jìn)行分析，得到在考慮了干濕循環(huán)條件覆蓋層毛細(xì)阻滯的效果評(píng)價(jià)，并通過(guò)數(shù)值模擬為后續(xù)的土柱試驗(yàn)提供參數(shù)；第三章通過(guò)土柱試驗(yàn)來(lái)驗(yàn)證數(shù)值模型，通過(guò)對(duì)試驗(yàn)結(jié)果的分析，得到干濕循環(huán)作用下覆蓋層效果評(píng)價(jià)的一些初步結(jié)論；第四章再通過(guò)數(shù)值模擬的方法，模擬一年干濕循環(huán)條件下毛細(xì)阻滯覆蓋系統(tǒng)，分析了不同材料厚度、不同地區(qū)、不同坡度和植物對(duì)毛細(xì)阻滯覆蓋層性能的影響，并最終給出毛細(xì)阻滯式覆蓋層的整體性能的綜合效果評(píng)價(jià)。研究結(jié)果表明： 土柱模型粗粒土和細(xì)粒土之間的毛細(xì)阻滯效果明顯，底部滲水量也能反映出這種效果。得出了不同氣候邊界條件下覆蓋層的毛細(xì)突破時(shí)間。濕潤(rùn)地區(qū)的毛細(xì)突破時(shí)間最早，但半濕潤(rùn)地區(qū)的滲漏量卻最大。 通過(guò)三組粉土與砂土組合的土柱試驗(yàn)，首先驗(yàn)證了數(shù)值模型的合理性，兩者的結(jié)論基本相符，土柱試驗(yàn)過(guò)程中，細(xì)粒土含水量遠(yuǎn)大于粗粒土，毛細(xì)阻滯效果明顯。濕潤(rùn)地區(qū)土柱共發(fā)生兩次滲漏，5#點(diǎn)也發(fā)生了兩次毛細(xì)突破，分析顯示，暴雨導(dǎo)致了毛細(xì)突破和滲漏的發(fā)生。 通過(guò)數(shù)值模擬的方法研究了一年干濕循環(huán)條件下覆蓋層的水量平衡狀況，以廣州為代表的濕潤(rùn)地區(qū)如果達(dá)到滲漏量為零的要求，所需的細(xì)粒土厚度為1.3m，，粗粒土厚度0.3m，同時(shí)，覆蓋層中需要種植相應(yīng)的植物以增大騰發(fā)量。在覆蓋層的設(shè)計(jì)中，細(xì)粒土的厚度對(duì)滲漏量的影響最大，坡度次之，粗粒土的厚度影響最小。覆蓋層細(xì)粒土的側(cè)向?qū)帕侩S著坡度的增大而增大，導(dǎo)排量的增大使得水分更多的排出土體，從而減小了滲漏量。以北京為代表的半濕潤(rùn)地區(qū)如果達(dá)到滲漏量為零的要求，所需的細(xì)粒土厚度為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.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TU411

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本文編號(hào)：2390574