發(fā)布時間：2018-06-12 19:36

  本文選題：人工堆山 + 土石混合體��； 參考：《南京大學(xué)》2015年碩士論文

【摘要】：隨著城市建設(shè)的發(fā)展,城市拆遷改造、河道清淤、礦山治理等工程將會產(chǎn)生大量的工程棄土和固體廢棄物,如何處理這些棄土和固體廢棄物是當(dāng)前研究的熱點(diǎn)。近年來,人工堆山工程的提出是有效解決城市固體廢棄物、處置環(huán)境巖土工程問題的重要舉措之一。人工堆山有別于自然山體,其邊坡堆載體常為工程棄土和固體廢棄物的混合體,故研究人工堆山邊坡堆載體的滲透性、膨脹性,以及降雨情況下人工堆山邊坡滲流場對人工堆山安全性和穩(wěn)定性的影響具有重要意義。本文以土石混合體模擬人工堆山邊坡堆載體,選取下蜀土作為細(xì)粒(土)材料,分別添加0%、15%、30%和45%含量的不規(guī)則形狀角礫,同時控制土石混合體的干密度,采用自行設(shè)計的新型滲透膨脹儀對土石混合體的滲透性及膨脹性進(jìn)行研究。運(yùn)用Geo-Studio有限元軟件中的滲流分析模塊和邊坡穩(wěn)定分析模塊,對鎮(zhèn)江某人工堆山在不同方案下降雨入滲過程中邊坡滲流場的動態(tài)變化進(jìn)行數(shù)值模擬,并結(jié)合極限平衡法,分析不同方案降雨過程中的邊坡穩(wěn)定性。本文的主要研究成果如下：(1)本文設(shè)計了一種新型滲透膨脹儀,在滿足土石混合體試樣尺寸要求的同時,可以在工程現(xiàn)場較快地測得原位或重塑試樣的滲透速率和膨脹量。(2)試驗(yàn)結(jié)果顯示,土石混合體的滲透速率隨含石量的增加而增加,兩者存在指數(shù)關(guān)系,滿足k=k0enp;而膨脹量隨著含石量的增加而減小,兩者存在線性關(guān)系；土石混合體的滲透速率隨干密度的增加而減小,膨脹量隨干密度的增加而增加；土石混合體的滲透膨脹率和膨脹含水率兩者存在較明顯的線性關(guān)系。且新型滲透膨脹儀所測得土石混合體的滲透速率與柔性壁滲透儀所得的飽和滲透速率規(guī)律具有一致性,兩者相差近一個數(shù)量級。(3)數(shù)值模擬結(jié)果顯示,降雨強(qiáng)度越大,邊坡土體內(nèi)的體積含水率變化范圍越大,坡體表面出現(xiàn)暫態(tài)飽和區(qū)的時間也越早；降雨持時越長,其影響深度和范圍也越大。坡腳處土體的體積含水率所受影響最大。(4)降雨入滲過程中,最先影響到的是邊坡表層的土體,表層土體的孔隙水壓力隨著降雨的持續(xù)而逐漸增大,直到孔隙水壓力為零。降雨過程中坡腳處的負(fù)孔隙水壓力最先上升到零,對邊坡穩(wěn)定性產(chǎn)生重要影響,應(yīng)在設(shè)計和治理時予以重視。(5)降雨強(qiáng)度越大,持續(xù)時間越長,雨水入滲的范圍也越大,入滲量越多,邊坡的安全系數(shù)下降的越快。且安全系數(shù)的最小值不是在降雨結(jié)束時刻出現(xiàn),而是存在一定時間的滯后性。
[Abstract]:With the development of urban construction, many engineering projects, such as urban demolition and reconstruction, river desilting, mine treatment and so on, will produce a large number of engineering abandoned soil and solid waste. How to deal with these abandoned soil and solid waste is a hot research topic at present. In recent years, artificial mountain building project is one of the most important measures to solve the problem of urban solid waste and environmental geotechnical engineering. The artificial mountain pile is different from the natural mountain body, and the slope pile carrier is usually a mixture of engineering abandoned soil and solid waste, so the permeability and expansibility of the artificial mountain slope pile carrier are studied. The influence of seepage field on the safety and stability of artificial mountain slope under rainfall is of great significance. In this paper, a mixture of earth and rock was used to simulate the carrier of artificial pile slope, and Xiashu soil was selected as fine grained (soil) material, and the irregular shape breccia with 30% and 45% content of 0 15% and 45% content was added, respectively, and the dry density of the mixture was controlled at the same time. The permeability and dilatability of soil and rock mixture were studied by a new type of osmotic dilatometer designed by ourselves. The seepage analysis module and slope stability analysis module of Geo-Studio finite element software are used to simulate the dynamic change of slope seepage field in the process of rainfall infiltration under different schemes, and combined with limit equilibrium method. The slope stability of different schemes during rainfall is analyzed. The main research results of this paper are as follows: (1) in this paper, a new type of osmotic dilatometer is designed, which meets the requirements of the sample size of soil-rock mixture at the same time. The permeability rate and expansion of in-situ or remolded samples can be measured quickly in the engineering site. The results show that the permeability rate of soil-rock mixture increases with the increase of rock content, and there is an exponential relationship between them. The content of swelling decreases with the increase of rock content, and there is a linear relationship between them, and the permeation rate of soil-rock mixture decreases with the increase of dry density, and the amount of expansion increases with the increase of dry density. There is an obvious linear relationship between the permeability expansion ratio and the swelling water content of the mixed soil and rock. The results of numerical simulation show that the infiltration rate of soil-rock mixture measured by the new dilatometer is consistent with the saturated permeability rate obtained by the flexible wall osmometer, and the difference between them is nearly an order of magnitude. The numerical simulation results show that the rainfall intensity is greater. The larger the variation range of volume water content in slope soil is, the earlier the transient saturation zone appears on the slope surface, and the longer the duration of rainfall is, the greater the depth and range of influence will be. In the process of rainfall infiltration, the first influence is on the surface soil of the slope. The pore water pressure of the surface soil increases gradually with the continuous rainfall, until the pore water pressure is zero. In the process of rainfall, the negative pore water pressure at the foot of the slope rises to zero first, which has an important effect on the slope stability. The greater the rainfall intensity and the longer the duration, the larger the Rain Water infiltration range should be paid attention to in the design and treatment. The more the infiltration, the faster the safety factor of the slope decreases. And the minimum value of safety factor does not appear at the end of rainfall, but has the lag of a certain time.
【學(xué)位授予單位】：南京大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TU43

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