本文選題：淮安膨脹土　切入點(diǎn)：膨脹力　出處：《上海大學(xué)》2013年碩士論文

【摘要】：隨著我國(guó)國(guó)民經(jīng)濟(jì)和交通運(yùn)輸事業(yè)的發(fā)展，高速公路作為一個(gè)國(guó)家走向現(xiàn)代化的橋梁，在現(xiàn)代交通業(yè)的建設(shè)中起著至關(guān)重要的作用。在我國(guó)龐大的高速公路網(wǎng)中，很多高速公路建設(shè)在膨脹土地基上。作為典型的“問(wèn)題”土，膨脹土地基容易在濕脹干縮的過(guò)程中開(kāi)裂破壞，其工程災(zāi)害問(wèn)題已引起我國(guó)工程界和學(xué)術(shù)界的高度關(guān)注。本論文在查閱和整理國(guó)內(nèi)外相關(guān)文獻(xiàn)基礎(chǔ)上，對(duì)取自江蘇省淮安地區(qū)的膨脹土進(jìn)行試驗(yàn)研究，具體做了如下幾個(gè)方面的研究工作： 1、通過(guò)一系列土的基本物理試驗(yàn)，得出了淮安膨脹土的基本物理性質(zhì)；根據(jù)試驗(yàn)結(jié)果，判斷出土樣顆粒級(jí)配良好，天然土樣處于軟塑狀態(tài)，該土樣屬于弱膨脹土，試驗(yàn)同時(shí)還得到了該土樣在飽和狀態(tài)下的壓縮指標(biāo)。 2、使用三軸試驗(yàn)儀對(duì)壓實(shí)淮安膨脹土進(jìn)行固結(jié)排水剪切試驗(yàn)，研究了其強(qiáng)度和變形特性，得到其抗剪強(qiáng)度指標(biāo)。試驗(yàn)結(jié)果表明：在相同初始孔隙比條件下，剪切時(shí)的圍壓對(duì)于壓實(shí)淮安膨脹土的應(yīng)力比-應(yīng)變曲線有明顯影響，圍壓較大的應(yīng)力比-應(yīng)變曲線較低，應(yīng)力比峰值也較��；剪切時(shí)圍壓較大的體變更傾向于剪縮。側(cè)向應(yīng)變也較小。在相同圍壓條件下，初始孔隙比對(duì)應(yīng)力比-應(yīng)變曲線稍有影響，對(duì)體變有明顯影響，初始孔隙比較大的更傾向于剪縮。 3、使用固結(jié)儀對(duì)壓實(shí)淮安膨脹土進(jìn)行浸水膨脹變形試驗(yàn)和膨脹力試驗(yàn)，研究其膨脹特性。試驗(yàn)結(jié)果表明：浸水引起的膨脹變形（膨脹率）隨著上覆荷載、初始含水量的增大而減小，隨著初始干密度增大而增大；在相同初始孔隙比條件下，浸水變形穩(wěn)定后的孔隙比和上覆荷載的對(duì)數(shù)呈線性關(guān)系；膨脹力隨初始孔隙比的減小而增大，且膨脹力與初始孔隙比呈良好的線性關(guān)系。 4、使用壓力板法、濾紙法和蒸汽平衡法三種不同控制或量測(cè)吸力的試驗(yàn)方法，分別對(duì)其壓實(shí)土樣進(jìn)行土水特性試驗(yàn)，得出了吸力范圍為0~378MPa的土水特征曲線。試驗(yàn)結(jié)果表明：初始干密度相近時(shí)，在低吸力范圍內(nèi)脫濕曲線和吸濕曲線有明顯的滯回現(xiàn)象，，當(dāng)吸力大于100MPa時(shí)，滯回現(xiàn)象基本消失。濾紙法測(cè)出的土水特征曲線落在主脫濕和主吸濕曲線的滯回圈內(nèi)；由蒸汽平衡法所得出的高吸力范圍土水特征曲線可以看出，吸力接近于1000MPa時(shí)含水量接近于零。根據(jù)濾紙法的試驗(yàn)結(jié)果，土水特征曲線用含水量和吸力關(guān)系表示時(shí)，不同初始干密度試樣的土水特征曲線相差不大，說(shuō)明干密度對(duì)此類土水特征曲線的影響不大；而用飽和度和吸力關(guān)系表示時(shí)，當(dāng)吸力較小時(shí)，干密度大的土水特征曲線處于干密度小的右上方，當(dāng)吸力較大時(shí)，干密度對(duì)土水特征曲線的影響逐漸減小。
[Abstract]:With the development of national economy and transportation in China, expressway, as a bridge to modernization, plays an important role in the construction of modern transportation industry.In the huge highway network of our country, many freeways are built on expansive soil foundation.As a typical "problem" soil, expansive soil foundation is easy to crack and destroy in the process of wet expansion and shrinkage, and its engineering disaster has attracted great attention of engineering and academic circles in China.On the basis of consulting and collating domestic and foreign relevant literature, this paper carries on the experimental research to the expansive soil from Huaian area of Jiangsu Province, and does the following research work:1. Through a series of basic physical tests of soil, the basic physical properties of Huai'an expansive soil are obtained, according to the test results, the particle gradation of soil sample is good, the natural soil sample is in soft plastic state, and the soil sample belongs to weakly expansive soil.At the same time, the compression index of the soil sample in saturated state was obtained.2. The consolidation and drainage shear tests of compacted Huai'an expansive soil were carried out by using a triaxial test instrument. The strength and deformation characteristics of the soil were studied, and the shear strength index was obtained.The larger confining pressure changes tend to shrink during shear.The lateral strain is also small.Under the same confining pressure, the initial porosity ratio has a slight effect on the stress-to-strain curve, which has obvious influence on the bulk deformation, and the larger initial porosity is more inclined to shear shrinkage.3. The swelling deformation test and expansion force test of compacted Huai'an expansive soil were carried out by means of consolidation instrument, and its expansion characteristics were studied.The experimental results show that the swelling deformation (expansion ratio) caused by soaking decreases with the increase of the initial water content and increases with the increase of the initial dry density, and under the same initial void ratio,The relationship between the porosity ratio and the logarithm of the overlying load is linear, and the expansion force increases with the decrease of the initial void ratio, and there is a good linear relationship between the expansion force and the initial void ratio.4. Using three test methods of controlling or measuring suction, pressure plate method, filter paper method and steam equilibrium method, the soil-water characteristics of compacted soil samples are tested, and the characteristic curves of soil and water with suction range of 0~378MPa are obtained.The experimental results show that the dehumidification curve and the hygroscopic curve have obvious hysteretic phenomena in the range of low suction when the initial dry density is close. When the suction is larger than 100MPa, the hysteretic phenomenon basically disappears.The soil-water characteristic curve measured by filter paper method falls in the hysteresis loop of the main dehumidification and main moisture absorption curves, and the soil-water characteristic curve in the high suction range obtained by steam equilibrium method shows that the water content is close to zero when the suction is close to that of 1000MPa.According to the test results of filter paper method, when soil water characteristic curve is expressed by water content and suction relationship, the difference of soil water characteristic curve of different initial dry density sample is not different, which indicates that dry density has little influence on soil water characteristic curve.When the saturation and suction relation are used, when the suction is small, the soil water characteristic curve with high dry density is in the upper right of the dry density, and the influence of dry density on the soil water characteristic curve decreases gradually when the suction is larger.
【學(xué)位授予單位】：上海大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2013
【分類號(hào)】：TU443

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