本文關(guān)鍵詞： 粉土 孔隙率 飽和度 土壓力 熱物理參數(shù)　出處：《太原理工大學》2017年碩士論文　論文類型：學位論文

【摘要】：粉土在我國廣泛分布。因其特殊的工程性質(zhì),在地基、路基中作為填土材料,粉土被認為是最差的材料之一。由于山西地區(qū)特殊的地形、地貌,在道路建設和工程建設中常采用填土技術(shù)。而填土的擊實質(zhì)量,直接關(guān)系到上部結(jié)構(gòu)的安全和正常運營。同時,建設地下交通體系是有效地緩解城市交通擁擠和用地短缺的重要途徑之一。因此,針對粉土擊實特性的研究,擊實過程中的土中應力特性研究以及準確獲得擊實粉土的熱物理性質(zhì)的研究,不僅補充完善了巖土材料擊實性能和熱物理性質(zhì)的認識,而且對解決工程實際問題具有重要意義。為此,本文針對山西地區(qū)的粉土進行了室內(nèi)擊實試驗,分析了擊實能、含水量、擊實次數(shù)和土層厚度對粉土擊實過程中的土壓力和擊實錘的沖擊力的影響;對擊實后的粉土測定熱物理參數(shù),分析了孔隙率和飽和度與三個熱物理參數(shù)的關(guān)系。試驗結(jié)果表明:(1)在同一擊實能下,分5層擊實時土樣的最優(yōu)含水量和最大干密度均略大于分3層擊實時的。(2)無論擊實含水量為多少,擊實第一層土時,實測的土中壓力隨著擊實次數(shù)的增加而提高,在最后一擊時達到最大值。而擊實錘的沖擊力在含水量與最優(yōu)含水量相差2%的范圍內(nèi),均不發(fā)生變化,維持在12.5k N左右。對第二層或第三層土進行擊實時,擊實含水量在最優(yōu)含水量的干側(cè),土中的壓力隨擊實次數(shù)增加而提高,但是提高幅度小于第一層時;在最優(yōu)含水量的濕側(cè)擊實時,土中的壓力從某一擊開始不再增加,保持不變。隨著含水量的增加,每層土的最終土壓力值和最大擊實錘沖擊力先增加后減小。隨著擊實能的增加,第一層土的最終土壓力值逐漸增加;對第二層土或第三層土進行擊實時,在最優(yōu)含水量和最優(yōu)含水量的偏干側(cè),每層土的最終土壓力值在增加;而在最優(yōu)含水量的偏濕側(cè),每層土的最終土壓力值逐漸減小。在最優(yōu)含水量的偏干側(cè),第一層土的最大擊實錘沖擊力隨著擊實能的增大幾乎不變,第二至五層土的最大沖擊力有所增加。土壓力隨著擊實厚度的增加以指數(shù)函數(shù)的形式降低。(3)土樣的導熱系數(shù)和比熱容隨著孔隙率的增大表現(xiàn)為線性減小,導溫系數(shù)則逐漸增大。隨著飽和度的增加,土樣的導熱系數(shù)和比熱容曲線均呈現(xiàn)先上升再下降的趨勢;導溫系數(shù)則相反,呈現(xiàn)先降低后增加的趨勢。另外,熱物理參數(shù)與孔隙率、飽和度均具有良好的相關(guān)性。
[Abstract]:Silt is widely distributed in China. Because of its special engineering properties, silt is regarded as one of the worst materials in foundation and roadbed. Fill technology is often used in road construction and engineering construction. The compaction quality of fill is directly related to the safety and normal operation of superstructure. The construction of underground traffic system is one of the important ways to effectively alleviate urban traffic congestion and land shortage. Therefore, the study on the characteristics of silt compaction. The study of the stress characteristics in the compaction process and the accurate obtaining of the thermophysical properties of the compacted silt not only complements the understanding of the compaction properties and thermophysical properties of the rock and soil materials. And it is of great significance to solve the practical problems of engineering. Therefore, this paper carried out laboratory compaction test for silt in Shanxi area, and analyzed compaction ability and water content. The influence of compaction times and soil thickness on soil pressure and impact force of compaction hammer during silt compaction; The relationship between porosity and saturation and three thermophysical parameters is analyzed for the silt determined by compaction. The experimental results show that the porosity and saturation are under the same compaction energy. The optimal moisture content and maximum dry density of the soil samples in 5 layers are slightly larger than that of the real time soil samples in 3 layers.) no matter how much the compacted water content is, the first layer soil is compacted. The measured pressure in the soil increases with the increase of compaction times and reaches the maximum at the last strike, while the impact force of the hammer does not change in the range of 2% between the water content and the optimum water content. The compaction water content is on the dry side of the optimum water content, and the pressure in the soil increases with the increase of compaction times. But when the increase is less than the first layer; At the wet side strike of the optimal water content, the pressure in the soil does not increase from a certain strike, and remains unchanged. With the increase of water content. The final earth pressure and the maximum hammer impact force of each layer of soil firstly increase and then decrease. With the increase of compaction energy, the final earth pressure value of the first layer of soil increases gradually. When the second layer soil or the third layer soil is hit in real time, the final soil pressure of each layer is increasing on the dry side of the optimal water content and the optimal water content. On the wet side of the optimal moisture content, the final soil pressure of each layer of soil gradually decreases. On the dry side of the optimum moisture content, the maximum impact force of the first layer of soil is almost unchanged with the increase of compaction energy. The maximum impact force of the second to fifth layer soil increases. The soil pressure decreases with the compaction thickness by exponential function.) the thermal conductivity and specific heat capacity of the soil sample decrease linearly with the increase of porosity. With the increase of saturation, the thermal conductivity and specific heat capacity curve of soil samples increased first and then decreased. On the contrary, the thermal conductivity coefficient decreased first and then increased. In addition, there was a good correlation between thermal physical parameters and porosity and saturation.
【學位授予單位】：太原理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TU411

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