深厚湿陷性黄土地区路基侧向防渗新结构模型试验研究

发布时间：2018-03-02 08:29

本文关键词： 湿陷性黄土灰土挤密桩灰土防渗墙模型试验　出处：《兰州交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：从黄土的分布可知,湿陷性黄土在我国占有很大的比例。湿陷性黄土最主要的特性就是其湿陷性,当黄土浸水后强度会急剧降低,伴随发生塌陷、下沉等工程灾害,而这些灾害会严重影响线路或建筑物的正常使用。尤其身处西北,在这个湿陷性黄土广阔分布的地区,想要进行铁路或公路的施工,消除或减小黄土的湿陷性变得尤为重要。在工程实际中,对于黄土的湿陷性,最常用的的方法就是防渗处理,因此本文结合黄土的湿陷性设计了一种新型的侧向防渗路基结构,通过理论分析以及在此基础的室内模型试验研究了该新型防渗结构在侧向防渗方面的效果,本文的主要工作有:首先,对黄土的基本性质做了描述,并讲述了黄土的湿陷机理,分析了挤密桩的挤密原理以及防渗机理,为后面的模型试验提供理论依据。其次,在机理分析的基础上进行了室内模型试验,设计了三组不同的试验工况,第一组不作处理,第二组和第三组分别采用灰土挤密桩和灰土地下防渗墙处理,并拿后两组的数据与不做处理的第一组工况做对比,试验得出,经过处理的后两组试验与第一组对比,水分的渗透速率明显降慢,防渗性能明显提高,这是因为挤密桩和防渗墙的处理使得土体密实度变大,渗透系数变小,加之材料本身也具有一定的隔水效果使得路基的抗渗效果显著提高。而灰土防渗墙处理的防渗效果较之灰土挤密桩还要更好,这跟灰土挤密桩的桩间距有关系,试验中采用的是2.5倍的桩间距,当桩间距不断缩小,防渗效果也会不断提升。最后,在分析含水量变化的同时对不同工况下路基的沉降量也做了对比,分析得出第三组处理后的路基沉降量最小,其次是第二组工况,而第一组工况的路基沉降量最大。这是因为防渗效果越好,水分进入路基的量就越小,使的路基发生湿陷变形的量就越小。
[Abstract]:From the distribution of loess, it can be seen that collapsible loess occupies a large proportion in China. The most important characteristic of collapsible loess is its collapsibility. These disasters can seriously affect the normal use of lines or buildings, especially in the northwest, where collapsible loess is widely distributed, and want to carry out railway or highway construction. It is particularly important to eliminate or reduce the collapsibility of loess. In engineering practice, the most commonly used method for loess collapsibility is anti-seepage treatment, so this paper designs a new lateral anti-seepage subgrade structure combined with loess collapsibility. Through theoretical analysis and laboratory model test, the effects of the new anti-seepage structure on lateral seepage control are studied. The main work of this paper is as follows: firstly, the basic properties of loess are described, and the collapsibility mechanism of loess is described. This paper analyzes the compaction principle and anti-seepage mechanism of compacted pile, which provides the theoretical basis for the model test. Secondly, the indoor model test is carried out on the basis of mechanism analysis, and three groups of different test conditions are designed, the first group does not deal with it. The second group and the third group were treated with lime-soil compaction pile and lime soil underground impervious wall respectively, and the data of the latter two groups were compared with the first working condition without treatment. The results of the experiment showed that the latter two groups were compared with the first group. The permeation rate of water decreased obviously and the impervious performance was improved obviously because the compaction pile and the cutoff wall made the compactness of soil become larger and the permeability coefficient decreased. In addition, the material itself also has a certain water barrier effect to improve the anti-seepage effect of roadbed significantly. But the impervious effect of lime-soil impervious wall is better than that of lime-soil compacted pile, which is related to the pile spacing of lime-soil compaction pile. In the test, the pile spacing is 2.5 times. When the pile spacing is reduced, the anti-seepage effect will be improved. Finally, the settlement of the roadbed under different working conditions is compared with the change of water content. The results show that the subgrade settlement of the third group is the smallest, the second group is the second, and the first group is the largest. This is because the better the anti-seepage effect, the smaller the amount of water entering the roadbed. The smaller the amount of collapsing deformation of the roadbed.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U213.1;U416.1

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