本文選題：非飽和土 + 桂林紅黏土�。� 參考：《北京交通大學(xué)》2017年碩士論文

【摘要】：土-水特征曲線(Soil Water Retention Curve)是描述非飽和土水力特性的重要關(guān)系曲線,它對非飽和土的諸多特性有影響,如滲透性、體變以及強度等。同時,作為解釋非飽和土行為的一項基本本構(gòu)關(guān)系,土-水特征曲線是將理論、試驗及預(yù)測方法有機結(jié)合的重要關(guān)系之一,也是構(gòu)筑非飽和土各種重要關(guān)系的基礎(chǔ)。因此,通過土-水特征曲線研究非飽和土的相關(guān)性質(zhì)具有重要的意義。影響土-水特征曲線的影響因素眾多,包括土的類型、應(yīng)力狀態(tài)、孔隙比、孔隙分布、初始含水量、吸力范圍、溫度以及化學(xué)成分等等�，F(xiàn)有研究表明,對于某一特定土樣,孔隙比是影響土-水特征曲線最為直接和重要的因素。然而,當(dāng)孔隙比相同時,不同微觀孔隙結(jié)構(gòu)的土樣卻表現(xiàn)出不同的土-水特征曲線性狀。地基、路基以及邊坡等實際工程中的土體,一方面由于受荷載作用而引起孔隙體積的減小;另一方面由于降雨、蒸發(fā)等氣候因素影響,天然土體處于干濕循環(huán)過程之中,其孔隙比和微觀孔隙結(jié)構(gòu)也將發(fā)生改變,從而導(dǎo)致其工程響應(yīng)的差異。為了研究不同孔隙結(jié)構(gòu)對非飽和土土-水特征曲線的影響,以桂林紅黏土為研究對象,首先自主研制單孔結(jié)構(gòu)泥漿土制樣裝置,利用固結(jié)法和壓實法分別制備單孔和雙孔結(jié)構(gòu)的土樣。隨后,基于軸平移法、濾紙法和飽和鹽溶液蒸汽平衡法3種不同控制吸力的方法,對上述兩種不同孔隙結(jié)構(gòu)以及不同初始孔隙比的共計129個桂林紅黏土土樣的土-水特征曲線開展了試驗研究。最后,利用壓汞法與掃描電鏡法,對泥漿土與壓實土樣在干化、濕化和干濕循環(huán)過程中不同吸力階段的微觀孔隙結(jié)構(gòu)進(jìn)行了試驗研究,揭示了單、雙孔結(jié)構(gòu)土樣在水力作用過程中微觀孔隙結(jié)構(gòu)的演化規(guī)律。取得的主要研究成果如下:(1)自主研制了單孔結(jié)構(gòu)泥漿土制樣裝置,對不同孔隙結(jié)構(gòu)土樣制備方法進(jìn)行了優(yōu)化。自主開發(fā)研制了一種單孔結(jié)構(gòu)泥漿土制樣裝置,其原理簡單、使用方便,能夠靈活地通過砝碼或千斤頂控制固結(jié)壓力,并可通過制樣桶的刻度以及量筒所測排水量,對所制備土樣的密度進(jìn)行有效控制;同時,基于所研制的泥漿土制樣裝置和傳統(tǒng)的壓實樣制樣器,對單孔結(jié)構(gòu)泥漿土和雙孔結(jié)構(gòu)壓實土試樣的制備方法進(jìn)行了優(yōu)化。(2)利用不同的吸力控制技術(shù),開展了全吸力范圍內(nèi)不同孔隙結(jié)構(gòu)桂林紅黏土的土-水特征曲線試驗研究,揭示了初始孔隙比和微觀孔隙結(jié)構(gòu)對土-水特征曲線的影響規(guī)律。針對桂林紅黏土,通過單孔結(jié)構(gòu)泥漿土制樣裝置制備3種初始孔隙比的單孔結(jié)構(gòu)重塑土,通過擊實法制備3種初始孔隙比的雙孔結(jié)構(gòu)重塑土。分別利用軸平移技術(shù)、濾紙法和飽和鹽溶液蒸汽平衡法,對不同吸力水平的吸力進(jìn)行控制,獲取了不同孔隙結(jié)構(gòu)和不同初始孔隙比條件下桂林紅黏土的土-水特征曲線,揭示了微觀孔隙結(jié)構(gòu)和初始孔隙比對土-水特征曲線的影響規(guī)律,包括對干化曲線、濕化曲線以及滯回特性的影響。(3)通過對土樣在干濕循環(huán)過程中的不同階段開展壓汞實驗和電鏡掃描實驗,揭示了單、雙孔結(jié)構(gòu)的桂林紅黏土在干濕循環(huán)過程中微觀結(jié)構(gòu)演化規(guī)律。利用壓汞實驗和掃描電鏡實驗,分別測試了 3種初始孔隙比的泥漿土樣與壓實土樣在干濕循環(huán)過程中不同吸力階段的微觀孔隙結(jié)構(gòu),包括干化過程和濕化過程,從而揭示了兩種不同孔隙結(jié)構(gòu)桂林紅黏土微觀孔隙結(jié)構(gòu)的演化規(guī)律,并重點分析了孔隙結(jié)構(gòu)類型對土-水特征曲線滯回特性的影響。
[Abstract]:The soil water characteristic curve (Soil Water Retention Curve) is an important relation curve to describe the hydraulic characteristics of unsaturated soils. It affects many properties of unsaturated soils, such as permeability, volume change and strength. At the same time, as a basic constitutive relation of unsaturated soil behavior, the soil water characteristic curve is the theory, test and prediction method. One of the important relationships of organic combination is also the basis for the construction of various important relationships of unsaturated soils. Therefore, it is of great significance to study the related properties of unsaturated soils by the soil water characteristic curve. There are many factors affecting the soil water characteristic curve, including soil type, stress state, pore ratio, pore distribution, initial water content and suction. Scope, temperature and chemical composition and so on. Existing studies have shown that the ratio of pores is the most direct and important factor affecting the soil water characteristic curve for a specific soil sample. However, the soil samples with different micro pore structures show different characteristics of soil water characteristic curve when the pores are compared with phase. On the one hand, the volume of the soil is reduced by the load action. On the other hand, due to the influence of rainfall and evaporation, the natural soil is in the dry and wet cycle, and the pore ratio and micropore structure will also change, which leads to the difference in the response of the soil. With the soil water characteristic curve and the soil water characteristic curve, Guilin red clay is the research object. First, single hole structure mud and soil sample preparation device is independently developed. The single hole and double hole structure are prepared by consolidation method and compaction method respectively. Then, 3 different methods of controlling suction based on axial translation method, filter paper method and saturated salt solution steam balance method are used. The soil water characteristic curves of 129 Guilin red clay samples with different pore structures and different initial pore ratios were studied. Finally, the micro pore structure of the mud soil and the compacted soil samples at different suction stages during dry, wet and dry wet cycles were studied by using the method of mercury injection and scanning electron microscopy. The evolution law of micro pore structure of single and double pore structure soil samples during hydraulic action is revealed. The main achievements are as follows: (1) the single hole structure mud and soil sample preparation device has been independently developed, and the preparation methods of soil samples with different pore structures have been optimized. It is simple in principle and convenient to use. It can control consolidation pressure by weight or Jack flexibly, and can control the density of the prepared soil by making the scale of the sample barrel and measuring the amount of water in the cylinder. At the same time, the mud soil and the traditional compacted sample are developed for the single hole structure mud soil and the double hole. The preparation method of the compacted soil sample was optimized. (2) the soil water characteristic curve of the Guilin red clay with different pore structure in the full suction range was carried out by using different suction control techniques, and the influence of the initial pore ratio and the micro pore structure on the soil water characteristic curve was revealed. In view of the Guilin red clay, the single soil water characteristic curve was revealed. A single pore structure remolded soil with 3 initial pore ratios is prepared by a hole structure mud soil sample preparation device. A double pore structure remolding soil with 3 initial pore ratios is prepared by compaction method. The suction forces of different suction levels are controlled by axial translation technique, filter paper method and saturated salt solution vapor equilibrium method, and different pore structures and different initial stages are obtained. The soil water characteristic curve of Guilin red clay under the initial pore ratio revealed the influence of the micro pore structure and initial pore ratio on the soil water characteristic curve, including the influence on the drying curve, the wetting curve and the hysteresis characteristics. (3) the pressure mercury experiment and the SEM scanning were carried out at different stages during the dry and wet cycle of the soil sample. The microscopic structure evolution of the single, double pore structure of Guilin red clay in the dry and wet cycle was revealed. The micro pore structure of the mud soil samples and compacted soil samples at different suction stages during the dry and wet cycle were measured by the mercury pressure test and the scanning electron microscope. The drying process and the wetting process were also tested, respectively. The evolution of micro pore structure of two different pore structures of Guilin red clay is revealed, and the effect of pore structure type on the hysteresis characteristics of soil water characteristic curve is analyzed.
【學(xué)位授予單位】：北京交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TU446

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 侯曉坤;李同錄;謝蕭;晁建紅;趙權(quán)利;張常亮;;甘肅Q_3原狀黃土的微觀結(jié)構(gòu)對其土-水特征曲線的影響[J];水利學(xué)報;2016年10期

2 劉毅;;高廟子膨潤土水化膨脹特性及其微觀機理研究[J];工程地質(zhì)學(xué)報;2016年03期

3 高游;孫德安;;制樣方法對非飽和土力學(xué)特性的影響[J];巖土工程學(xué)報;2016年08期

4 萬勇;薛強;吳彥;趙立業(yè);;干濕循環(huán)作用下壓實黏土力學(xué)特性與微觀機制研究[J];巖土力學(xué);2015年10期

5 孫德安;高游;劉文捷;韋昌富;張升;;紅黏土的土水特性及其孔隙分布[J];巖土工程學(xué)報;2015年02期

6 孫德安;高游;;不同制樣方法非飽和土的持水特性研究[J];巖土工程學(xué)報;2015年01期

7 吳s，

本文編號：1916914