本文選題：膨脹土　切入點：微觀結構　出處：《長安大學》2015年博士論文　論文類型：學位論文

【摘要】：膨脹土是膨脹土地區(qū)公路路基塌陷、崩解、隆起等病害的主要原因。膨脹土遇水膨脹、失水收縮后使得膨脹土體產(chǎn)生裂縫,且反復性較強,嚴重影響了工程建設的進度,加大了膨脹土地區(qū)公路建設的難度,是公路建設質量和公路運行安全的隱患。當膨脹土膨脹性較弱時,可在工程建設中使用,但弱膨脹土分類較為粗略,針對性不強,因此,對弱膨脹土進行試驗研究,制定弱膨脹土分級標準、路基填料分級標準和邊坡坡度標準對于制定弱膨脹土地區(qū)路基邊坡處治控制標準具有重要意義。通過系統(tǒng)分析目前國內外相關研究成果,采用理論研究和試驗分析相結合的方法對隴南地區(qū)弱膨脹土的細化分級標準、采用弱膨脹土作為填料和路塹邊坡坡度控制技術標準進行研究。利用掃描電鏡和XRD試驗對甘肅省隴南地區(qū)弱膨脹土從微觀角度進行膨脹性分析,通過對膨脹土的微觀形態(tài)和礦物成分的定性和定量的研究,揭示了弱膨脹土具有膨脹性的內在機理,為分析弱膨脹土的工程特性提供依據(jù)。通過膨脹土土工試驗,分析了甘肅省隴南地區(qū)弱膨脹土的基本性質,并在無荷載和有荷載膨脹率試驗的基礎上,研究了含水率、干密度等影響因素與膨脹土膨脹性的關系,并以此推導出弱膨脹土無荷載和有荷載膨脹率預估公式,為提出弱膨脹土細化分類標準和弱膨脹土填料填筑分級標準和路塹邊坡坡度控制標準奠定基礎。對膨脹土膨脹性判別指標進行分析,并結合甘肅省隴南地區(qū)弱膨脹土的膨脹性能,將膨脹土膨脹性分類指標進行細化,制定弱膨脹土膨脹性分級指標。在膨脹土膨脹性試驗的基礎上,對弱膨脹土膨脹性分級指標進行判別對比分析。在膨脹土膨脹力試驗的基礎上,基于膨脹土上覆荷載壓力與膨脹力平衡的思想,制定弱膨脹土作為填料時的上覆路基厚度標準。并采用FLAC-3D軟件對弱膨脹土填料填筑標準進行驗證。根據(jù)弱膨脹土分級標準對弱膨脹土邊坡坡度進行分級。并制定十天高速公路甘肅段膨脹土分布路段處治措施。
[Abstract]:Expansive soil is the main cause of road subgrade collapse, collapse, uplift and other diseases in expansive soil area. The difficulty of highway construction in expansive soil area is increased, which is the hidden danger of highway construction quality and highway running safety. When expansive soil is weak, it can be used in engineering construction, but the classification of weak expansive soil is rough and the pertinence is not strong. The weak expansive soil was tested and studied, and the classification standard of weak expansive soil was established. The classification standard of subgrade filler and slope gradient standard are of great significance to establish the control standard of subgrade slope treatment in weakly expansive soil area. The method of combining theoretical research with experimental analysis is used to classify the weak expansive soil in Longnan area. Using weakly expansive soil as filler and slope control standard of cutting slope, the swelling property of weakly expansive soil in Longnan area of Gansu Province was analyzed by scanning electron microscope (SEM) and XRD test. Through the qualitative and quantitative study on the microscopic morphology and mineral composition of expansive soil, the inherent mechanism of dilatancy of weakly expansive soil is revealed, which provides a basis for analyzing the engineering characteristics of weakly expansive soil. The basic properties of weakly expansive soil in Longnan area of Gansu Province are analyzed. On the basis of the test of no load and load expansion rate, the relationship between water content, dry density and swelling property of expansive soil is studied. Based on this, the formulas for predicting the expansion rate of weakly expansive soil without load and load are derived. It lays a foundation for the classification standard of weak expansive soil, the standard for filling and grading of weak expansive soil and the control standard for slope gradient of cutting slope. The discriminant indexes of expansive soil are analyzed. Combining with the expansive property of weak expansive soil in Longnan area of Gansu Province, the expansive property classification index of expansive soil is refined, and the classification index of expansive property of weak expansive soil is established. Based on the test of expansive force of expansive soil and the thought of equilibrium of overburden pressure and expansion force on expansive soil, the classification index of dilatancy of weakly expansive soil is analyzed. The overlying subgrade thickness standard when weak expansive soil is used as filler is formulated, and the filling standard of weak expansive soil is verified by FLAC-3D software. According to the classification standard of weak expansive soil, the slope of weak expansive soil slope is classified, and the slope of weak expansive soil slope is determined. Treatment measures of expansive soil distribution section in Gansu section of ten-day expressway.
【學位授予單位】：長安大學
【學位級別】：博士
【學位授予年份】：2015
【分類號】：U416.1

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本文編號：1570892