高速公路含砂低液限粘土路基结构研究

发布时间：2018-06-18 11:22

本文选题：含砂低液限粘土 + 水稳定性　；参考：《北京交通大学》2017年硕士论文

【摘要】：含砂低液限粘土分布广泛,成分和性质特殊。在修筑高速公路时,废弃的含砂低液限粘土的处理及填土的来源是一个棘手的问题,若处理不当,既造成资源浪费,又增加了施工成本。本文依托福建省莆永高速公路路基填筑工程,结合当地的具体条件,通过试验及ABAQUS模拟,旨在考虑不同因素影响下含砂低液限粘土路基的受力与变形特性,从而提出优化的路基结构形式。本文的主要研究内容及结论如下:(1)通过对室内试验数据进行分析整理,研究了莆永高速公路沿线含砂低液限粘土的物理力学性质,包括:级配、液塑限、击实特性、CBR、抗剪强度、回弹模量等。试验结果表明:含砂低液限粘土的水稳定性极差,在莆永高速公路沿线降雨丰富、地下水位较高的情况下,含砂低液限粘土填筑的路基的稳定性及变形特性堪忧。(2)研究了石灰、水泥改良后含砂低液限粘土的CBR、回弹模量等,提出了莆永高速公路沿线含砂低液限粘土采用石灰、水泥改良时的合理掺入剂量。(3)利用ABAQUS软件,模拟了在设计使用年限内的交通荷载作用下,不同路基高度、不同下路堤改良层厚度时路基的受力与变形特性,以沥青混凝土路面层底容许弯拉应力为控制条件,提出了含砂低液限粘土填筑路基时下路堤的合理改良厚度。(4)利用ABAQUS软件,研究了地下水毛细作用及降雨入渗作用对含砂低液限粘土路基的稳定性及变形的影响。结果表明:地下水毛细作用对于高度低于17.5m的路基有不利影响。边坡降雨入渗对含砂低液限粘土路基的差异沉降量影响不明显,但对边坡稳定性有不利影响。受到路基边坡雨水渗入的影响,沿着入渗区和干燥区的分界面出现滑移面,路基的整体稳定性降低。(5)利用ABAQUS软件,模拟了采用隔断层、粘土包边等措施处理后含砂低液限粘土路基的受力与变形特性,提出了潮湿、多雨地区含砂低液限粘土路基的结构形式。
[Abstract]:Sand-bearing clay with low liquid limit is widely distributed with special composition and properties. In the construction of freeway, the disposal of abandoned low-liquid clay containing sand and the source of filling is a thorny problem. If not treated properly, it will not only cause waste of resources, but also increase the cost of construction. Based on the embankment filling project of Puyong Expressway in Fujian Province, combined with the local specific conditions, through tests and Abaqus simulation, this paper aims to consider the mechanical and deformation characteristics of low-liquid clay subgrade bearing sand under the influence of different factors. Thus, the optimized subgrade structure form is put forward. The main contents and conclusions of this paper are as follows: (1) the physical and mechanical properties of low-liquid clay containing sand along Puyong Expressway are studied through the analysis and collation of laboratory test data, including gradation, liquid-plastic limit, compaction characteristics, CBR, shear strength, etc. Modulus of resilience, etc. The test results show that the water stability of low liquid limit clay containing sand is extremely poor. Under the condition of abundant rainfall and high groundwater level along Puyong Expressway, the stability and deformation characteristics of subgrade filled with low liquid limit clay containing sand are studied. The CBR, springback modulus and so on of low liquid limit clay containing sand after cement improvement are put forward. It is put forward that the sand containing low liquid limit clay along Puyong Expressway is lime, and the reasonable mixing dose of cement is improved by using Abaqus software. Under the action of traffic load in the design service life, the stress and deformation characteristics of the subgrade are simulated under different embankment height and the improved layer thickness of the lower embankment. The allowable bending and tensile stress at the bottom of the asphalt concrete pavement is taken as the control condition. The reasonable improved thickness of embankment under filling embankment with sand and low liquid limit clay is put forward. Using Abaqus software, the effects of groundwater capillary and rainfall infiltration on stability and deformation of embankment with sand and low liquid limit are studied. The results show that the capillary effect of groundwater has a negative effect on the roadbed with height below 17.5m. The effect of rainfall infiltration on the differential settlement of low liquid limit clay subgrade with sand is not obvious, but it has a negative effect on slope stability. Affected by Rain Water infiltration of embankment slope, slip surface appears along the interface between infiltration zone and dry area, and the overall stability of roadbed is reduced. 5) Abaqus software is used to simulate the use of separated fault. The mechanical and deformation characteristics of low liquid limit clay roadbed with sand after treatment with clay-embossed edges are discussed. The structural form of low-liquid clay roadbed with sand in humid and rainy areas is proposed.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U416.1

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