基于堆积理论的球形轻质材料路基设计方法研究
发布时间:2018-04-12 18:20
本文选题:球形轻质材料 + 堆积理论 ; 参考:《哈尔滨工业大学》2015年硕士论文
【摘要】:路基不仅是道路的结构支撑物,而且是道路的主要承重体。它不仅承受自身和路面结构的自重,而且还承担着从路面传递下来的车辆荷载。因此坚固而又稳定的路基为路面结构长期承受汽车荷载提供了重要保证。但是,工程中常见的问题如路基不均匀沉降、软土地基等严重影响了道路的使用性能,因此寻找一种高效、稳定的路基填筑技术显得至关重要。球形轻质材料路基填筑技术是一种新型、快速、稳定、轻质、环保的路基填筑技术,已经在城市道路的快速抢修工作中得到了初步应用,并取得了良好的效果,但球形轻质材料应用于公路路基上的研究尚未开展,而且在理论上仍缺少系统的研究。因此,文章将开展球形轻质材料路基设计方法研究,研究球形轻质材料堆积时的力学响应以及应力传递,分析其稳定性,并提出适合于球形轻质路基的边坡形式,主要研究内容包括:首先,通过正交试验设计方法,从泡沫轻质土的制作原理出发,对泡沫轻质土进行配合比设计研究。在前人已有的泡沫混凝土配合比设计方法的基础上进行改进,以水泥和泡沫为基本混合料,再向其中掺入一定量粉煤灰和矿粉进行配合比设计研究,分析不同材料掺量对泡沫轻质土强度的影响,并利用正交试验设计方法进行多因素配合比设计分析,得出最佳配合比为水料比0.45,粉煤灰掺量20%,矿粉掺量10%,泡沫掺量4%。其次,根据球形轻质材料的特性以及接触方式的特点,探讨了离散元颗粒流程序中的接触本构模型以及微观与宏观参数之间的关系,结合球形轻质材料室内力学性能试验结果,确定离散元模拟时所需的各类参数以及接触模型。再次,采用离散元颗粒流程序,基于堆积理论对球形轻质材料不同排列组合形式进行数值模拟,并对球形轻质材料路基不同深度下的应力分布进行分析,从力链分布和接触力的角度分析球形轻质材料的结构中应力传递路径。通过室内试验测试单排球形轻质材料规则排列下的接触力,与模拟结果基本吻合。最后,通过离散单元法模拟,分析球形轻质材料路基的侧向力分布以及不同宽度土坡的侧向力分布,确定能够约束球形轻质材料路基的土坡宽度,并进行边坡稳定性验算。根据不同路基高度的边坡稳定性安全系数,确定适合设置培土边坡的临界值,超过临界值设置加筋土挡墙,并进行加筋土挡墙验算。
[Abstract]:The roadbed is not only the structural support of the road, but also the main bearing body of the road.It not only bears the weight of itself and the pavement structure, but also bears the vehicle load transferred from the road surface.Therefore, the strong and stable roadbed provides an important guarantee for the pavement structure to bear the vehicle load for a long time.However, common problems in engineering such as uneven settlement of roadbed, soft soil foundation and other serious impact on the performance of the road, so it is very important to find an efficient and stable subgrade filling technology.The subgrade filling technology of spherical lightweight material is a new, fast, stable, light and environmentally friendly subgrade filling technology, which has been applied in the rapid repair of urban roads and has achieved good results.However, the application of spherical lightweight materials to highway subgrade has not been carried out, and there is still a lack of systematic research in theory.Therefore, the paper will study the design method of spherical lightweight subgrade, study the mechanical response and stress transfer when spherical lightweight material accumulates, analyze its stability, and put forward the slope form suitable for spherical lightweight roadbed.The main research contents are as follows: first, through the orthogonal design method, according to the principle of making foam lightweight soil, the proportion design of foam lightweight soil is studied.On the basis of the existing design method of foamed concrete mix ratio, cement and foam are taken as the basic mixture, and a certain amount of fly ash and mineral powder are added into the mixture to study the mix ratio design.The influence of different material content on the strength of light foamed soil is analyzed. The optimum mix ratio is 0.45 for water and material, 20 for fly ash, 10 for mineral powder and 4 for foam.Secondly, according to the characteristics of spherical lightweight material and contact mode, the contact constitutive model in discrete element particle flow program and the relationship between microscopic and macroscopic parameters are discussed.The parameters and contact model of discrete element simulation are determined.Thirdly, the discrete element particle flow program is used to simulate the different arrangement and combination forms of spherical lightweight materials based on stacking theory, and the stress distribution at different depths of spherical lightweight subgrade is analyzed.The stress transfer paths in the structure of spherical lightweight materials are analyzed from the angle of force chain distribution and contact force.The contact force under the regular arrangement of single row spherical lightweight materials was tested by laboratory test, and the results were in good agreement with the simulation results.Finally, the lateral force distribution of spherical lightweight subgrade and the lateral force distribution of soil slope with different widths are analyzed by means of discrete element method, and the slope width which can be restrained by spherical light material subgrade is determined, and the slope stability is checked.According to the safety factor of slope stability at different embankment heights, the critical value of soil slope is determined, the reinforced earth retaining wall is set over the critical value, and the reinforced earth retaining wall is checked and calculated.
【学位授予单位】:哈尔滨工业大学
【学位级别】:硕士
【学位授予年份】:2015
【分类号】:U416.1
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