改良弱胶结砂岩填料路用性能试验研究

发布时间：2019-03-21 19:44

【摘要】：交通运输作为我国西部大开发进一步推进及深化的基础性事业,公路、铁路等基建工程与这一伟大事业息息相关,然而作为西北地区交通枢纽中心的兰州却处于典型的弱胶结砂岩地层区,若能够将弱胶结砂岩填料用于路基填筑工程,将具有重要的经济、环境和社会效益。本文以兰州地区弱胶结砂岩地层为研究对象,以资料调研、现场取样试验测定、利用水泥对填料改良试验测定和数值模拟分析四个方面展开对其工程特性的系统研究。文中通过室内膨胀性试验及崩解性试验探讨了弱胶结砂岩的膨胀性机理和崩解性机理;通过一系列室内土工试验对弱胶结砂岩填料的物理力学性能及水泥改良弱胶结砂岩填料的路用性能进行了深入研究;利用ANSYS软件对不同填料工况的路基模型沉降变形量进行数值模拟分析,得到以下研究成果:(1)弱胶结砂岩具有膨胀特性及崩解特性,若能够通过合理的施工工艺将弱胶结砂岩岩块预先进行机械破碎,使岩块崩解趋于稳定状态,并严格控制含水率,在避免出现较大的膨胀变形破坏前提下,考虑将弱胶结砂岩填料作为铁路路基填料非常具有研究价值。(2)通过对弱胶结砂岩填料物理力学性能的试验结果研究发现:未改良弱胶结砂岩填料的力学性能并不满足作为铁路路基填料的技术要求,不能直接用于路基填筑。(3)不同配合比的水泥改良弱胶结砂岩填料的路用性能试验研究结果表明:水泥对于弱胶结砂岩填料的压缩性能、力学性能、承载力性能等路用性能改良效果显著;配合比达到6%以上的水泥改良混合料即满足作为铁路路基填料的技术要求,又具有足够的安全储备,综合考虑经济效益,建议将6%作为水泥改良弱胶结砂岩填料的最佳配合比。(4)以不同配合比的水泥改良弱胶结砂岩填料所填筑的路基为研究对象,利用ANSYS软件对不同工况条件的路基模型在自重及上部静荷载的综合作用下的沉降变形规律进行数值模拟分析,分析结果充分验证了将6%作为水泥改良弱胶结砂岩填料的最佳配合比的可行性。
[Abstract]:As a basic undertaking to further promote and deepen the development of the western region of our country, transportation and other infrastructure projects such as roads and railways are closely related to this great cause. However, Lanzhou, as the center of the transportation hub in northwest China, is in the typical weak cemented sandstone stratum area. If the weak cemented sandstone filler can be used in roadbed filling projects, it will have important economic, environmental and social benefits. In this paper, the weak cemented sandstone formation in Lanzhou area is taken as the research object, and the engineering characteristics are systematically studied in four aspects: data investigation, field sampling test determination, cement-to-filler improvement test determination and numerical simulation analysis. In this paper, the expansibility mechanism and collapsibility mechanism of weakly cemented sandstone are discussed by laboratory expansion test and disintegration test. A series of laboratory geotechnical tests were carried out to study the physical and mechanical properties of weakly cemented sandstone fillers and the road performance of cement modified weakly cemented sandstone fillers. By using ANSYS software, the settlement deformation of subgrade model under different filling conditions is simulated and analyzed. The results are as follows: (1) the weak cemented sandstone has expansion and disintegration characteristics, and the results are as follows: (1) weak cemented sandstone has expansion and disintegration characteristics. If the weak cementitious sandstone block can be mechanically broken in advance through reasonable construction technology, the rock block collapse will tend to a stable state, and the moisture content will be strictly controlled, so as to avoid large expansion and deformation failure. It is of great value to consider weak cemented sandstone fillers as railway roadbed fillers. (2) through the experimental study on physical and mechanical properties of weakly cemented sandstone fillers, it is found that the mechanical properties of unmodified weakly cemented sandstone fillers are of great value. Can not meet the technical requirements for filling the railway roadbed, It can not be directly used in roadbed filling. (3) the road performance of cement modified weak cemented sandstone fillers with different mix ratios shows that: the compressive and mechanical properties of cement to weakly cemented sandstone fillers; The improvement effect of bearing capacity and other road performance is remarkable; The cement-modified mixture with mixture ratio of more than 6% not only meets the technical requirements of filling railway subgrade, but also has sufficient safety reserve and comprehensive consideration of economic benefits. It is suggested that 6% should be the best mix ratio of cement modified weakly cemented sandstone fillers. (4) the roadbed filled with cement modified weakly cemented sandstone fillers with different mix ratios is the research object of study. The settlement deformation law of subgrade model under different working conditions under the combined action of dead weight and upper static load is numerically simulated and analyzed by using ANSYS software. The analysis results fully verify the feasibility of using 6% as the best mix ratio of cement modified weak cemented sandstone filler.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U416.1

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