本文關(guān)鍵詞： 鹽漬土 路基 側(cè)隔下疏 小模型試驗(yàn) 現(xiàn)場試驗(yàn)路段　出處：《塔里木大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：針對南疆鹽漬土道路的凍脹、溶陷、翻漿等典型的道路破壞問題，以南疆阿拉爾市為依托，從改變鹽漬土路基結(jié)構(gòu)的方面考慮來防治鹽漬土路基鹽脹、凍脹、溶陷等病害的方法，提出了“側(cè)隔下疏”的新型鹽漬土路基結(jié)構(gòu)形式，對研究區(qū)域的鹽漬土進(jìn)行取樣測定其含水率、密度、顆粒級配等基本參數(shù)并通過配制土樣進(jìn)行導(dǎo)熱系數(shù)、滲透系數(shù)、凍脹試驗(yàn)等相關(guān)實(shí)驗(yàn)；通過室內(nèi)路基結(jié)構(gòu)小模型實(shí)驗(yàn),對路基兩種不同形式坡度的疏水層進(jìn)行對比分析研究，在“側(cè)隔下疏”型路基結(jié)構(gòu)中,疏水層、隔斷層如何設(shè)置對鹽漬土路基的鹽脹病害可以減少；并對“側(cè)隔下疏”式路基結(jié)構(gòu)形式應(yīng)用進(jìn)行了理論分析，以阿拉爾市城市道路改建工程為現(xiàn)場試驗(yàn)并通過對其路基物理力學(xué)特性變形的監(jiān)測得出如下結(jié)論： （1）路基中凍土層的形成對土壤中水、鹽的遷移有很大影響，進(jìn)而影響到鹽漬土路基中鹽分的分布。 （2）試樣滲透系數(shù)隨著干密度的增大而減小逐漸趨于恒定,隨著密度的增大，土顆粒之間的空隙不斷減小，阻礙了滲透，使不同干密度的土壤與滲透系數(shù)的關(guān)系相對比較復(fù)雜。當(dāng)干密度較大時(shí),滲透系數(shù)隨壓實(shí)度的增大而減�。辉谳^小干密度情況下,滲透系數(shù)隨壓實(shí)度的增大而增大,不均勻系數(shù)為10時(shí),滲透系數(shù)達(dá)到極值,然后隨密實(shí)度的增大而增大。 （3）對試樣的導(dǎo)熱系數(shù)有影響的有含水量、含鹽量和干密度,對導(dǎo)熱系數(shù)影響最大的為含鹽量,其次為含水量,干密度對導(dǎo)熱系數(shù)的影響相對最小。導(dǎo)熱系數(shù)隨著干密度和含水量的增加而減小，隨含鹽量的增加而增大。 （4）對于不含鹽的土樣，隨著溫度的降低只發(fā)生凍脹變形，單純發(fā)生凍脹變形的土體總體變形量比較平緩，在消融后基本能恢復(fù)到初始狀態(tài)；而當(dāng)鹽漬土發(fā)生鹽凍脹變形時(shí)，隨著時(shí)間的增加，變形量呈現(xiàn)有規(guī)律的上升狀態(tài)，每次消融后都會(huì)有變形殘余。 （5）新型路基的小模型試驗(yàn)中通過設(shè)置不同坡度的隔斷層，隔斷層有傾角的能有效的加快排鹽，同時(shí)能夠增大排鹽量、提高了排鹽的效果；對于V型隔斷層,角度并不是越大效果就會(huì)越好,而是有一個(gè)臨界值是10°-15°；對于DV型隔斷層,其效果是隨著角度的增大而越來越明顯,最后確定隔斷層的角度10°為最佳角度。 （6）側(cè)隔下疏型路基結(jié)構(gòu)中由于隔斷層的存在,隔斷林帶水進(jìn)入路基凍土層，在外部溫度的變化下減少溫度對水分及鹽分遷移的影響；側(cè)隔下疏型路基結(jié)構(gòu)中由于下疏導(dǎo)層能疏導(dǎo)一部分路基內(nèi)部水分,阻止毛細(xì)水上升到凍土層，，抑制路基表面的泛鹽,減小了路基表面的鹽脹和凍脹變形量。 （7）現(xiàn)場試驗(yàn)還在一個(gè)自我平衡的時(shí)期，路基防鹽脹的優(yōu)越性還需要一個(gè)長期的檢測分析。
[Abstract]:In view of the typical road damage problems, such as frost heaving, dissolving, and churning of the salinized soil road in the south of Xinjiang, taking Alar city of southern Xinjiang as the basis, considering the change of the subgrade structure of the salinized soil to prevent the salt heaving and frost heaving of the salinized soil roadbed, In this paper, a new type of subgrade structure of salinized soil is put forward, by which the basic parameters, such as moisture content, density, particle gradation and so on, are measured by sampling the saline soil in the study area, and the thermal conductivity of the soil sample is obtained by preparing the soil sample. Permeability coefficient, frost heaving test and so on, through the indoor subgrade structure small model experiment, carries on the contrast analysis to the subgrade two kinds of different forms of slope hydrophobic layer, in "the side partition is sparse" the type subgrade structure, the hydrophobic layer, How to set up the separated fault to reduce the salt swelling disease of the saline soil subgrade, and the application of the structural form of the "side off and sparse" subgrade is analyzed theoretically. Taking the urban road reconstruction project of Alar City as the field test and monitoring the deformation of its roadbed physical and mechanical properties, the following conclusions are drawn:. 1) the formation of permafrost in the subgrade has a great influence on the migration of water and salt in the soil, and then affects the distribution of the salt in the subgrade of the saline soil. (2) with the increase of dry density, the permeability coefficient of the sample tends to be constant, and with the increase of the density, the void between soil particles decreases, which hinders the permeability. The relationship between soil permeability coefficient and soil permeability coefficient of different dry density is relatively complicated. When dry density is high, permeability coefficient decreases with the increase of compaction degree, and with the increase of compaction degree, the permeability coefficient increases with the increase of compaction degree when dry density is small. The inhomogeneity coefficient is 10:00, the permeability coefficient reaches the extreme value, and then increases with the increase of compactness. (3) the moisture content, salt content and dry density have the most influence on the thermal conductivity of the sample, and the salt content and the water content have the greatest influence on the thermal conductivity of the sample. The effect of dry density on thermal conductivity is relatively minimal. The thermal conductivity decreases with the increase of dry density and water content, and increases with the increase of salt content. 4) for soil samples without salt, only frost-heaving deformation occurs with the decrease of temperature, and the total deformation amount of soil with only frost-heaving deformation is relatively gentle, which can be basically restored to its initial state after ablation, but when salinized soil is subjected to salt-heaving deformation, With the increase of time, the amount of deformation increases regularly, and there will be residual deformation after each ablation. 5) in the small model test of the new subgrade, the inclined fault can accelerate the salt discharge effectively by setting different slope isolation faults, and at the same time, it can increase the amount of salt discharge and improve the effect of salt removal. The greater the angle is, the better the effect will be, but there is a critical value of 10 擄-15 擄. For DV type isolated fault, the effect becomes more and more obvious with the increase of angle. Finally, the angle of 10 擄is determined as the best angle. (6) because of the existence of separated fault, the water of separated forest belt enters the permafrost of roadbed, and the influence of temperature on water and salt migration is reduced with the change of external temperature. In the subgrade structure with side separation, the lower layer can drain a part of the subgrade internal moisture, prevent the capillary water from rising to the permafrost, restrain the oversalt on the surface of the roadbed, and reduce the amount of salt heave and frost heave deformation on the surface of the subgrade. The field test is still in a period of self-balance, and the superiority of anti-salt expansion of roadbed needs a long-term test and analysis.
【學(xué)位授予單位】：塔里木大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：U416.16

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