陇南地区高速公路膨胀土路基处治技术研究

发布时间：2018-03-05 15:49

本文选题：膨胀土　切入点：微观结构　出处：《长安大学》2015年博士论文　论文类型：学位论文

【摘要】：膨胀土是膨胀土地区公路路基塌陷、崩解、隆起等病害的主要原因。膨胀土遇水膨胀、失水收缩后使得膨胀土体产生裂缝,且反复性较强,严重影响了工程建设的进度,加大了膨胀土地区公路建设的难度,是公路建设质量和公路运行安全的隐患。当膨胀土膨胀性较弱时,可在工程建设中使用,但弱膨胀土分类较为粗略,针对性不强,因此,对弱膨胀土进行试验研究,制定弱膨胀土分级标准、路基填料分级标准和边坡坡度标准对于制定弱膨胀土地区路基边坡处治控制标准具有重要意义。通过系统分析目前国内外相关研究成果,采用理论研究和试验分析相结合的方法对陇南地区弱膨胀土的细化分级标准、采用弱膨胀土作为填料和路堑边坡坡度控制技术标准进行研究。利用扫描电镜和XRD试验对甘肃省陇南地区弱膨胀土从微观角度进行膨胀性分析,通过对膨胀土的微观形态和矿物成分的定性和定量的研究,揭示了弱膨胀土具有膨胀性的内在机理,为分析弱膨胀土的工程特性提供依据。通过膨胀土土工试验,分析了甘肃省陇南地区弱膨胀土的基本性质,并在无荷载和有荷载膨胀率试验的基础上,研究了含水率、干密度等影响因素与膨胀土膨胀性的关系,并以此推导出弱膨胀土无荷载和有荷载膨胀率预估公式,为提出弱膨胀土细化分类标准和弱膨胀土填料填筑分级标准和路堑边坡坡度控制标准奠定基础。对膨胀土膨胀性判别指标进行分析,并结合甘肃省陇南地区弱膨胀土的膨胀性能,将膨胀土膨胀性分类指标进行细化,制定弱膨胀土膨胀性分级指标。在膨胀土膨胀性试验的基础上,对弱膨胀土膨胀性分级指标进行判别对比分析。在膨胀土膨胀力试验的基础上,基于膨胀土上覆荷载压力与膨胀力平衡的思想,制定弱膨胀土作为填料时的上覆路基厚度标准。并采用FLAC-3D软件对弱膨胀土填料填筑标准进行验证。根据弱膨胀土分级标准对弱膨胀土边坡坡度进行分级。并制定十天高速公路甘肃段膨胀土分布路段处治措施。
[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.
【学位授予单位】：长安大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U416.1

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