回填轻量土—支挡结构联体模型在陡坡路基中的模拟应用研究

发布时间：2018-07-25 13:49

【摘要】：我国疆域辽阔,山区众多,大山一直是阻碍经济交通发展的重要屏障。由于受到地形、地貌、环境与投资等因素的影响,建造公路时经常会遇到在陡坡上修筑填方路基的问题。在陡坡上修筑回填路基过程中,由于普通回填土具有高压缩性、自重大等特点,选用普通回填土作为路基会对陡坡稳定性带来较大不良影响。随着回填路基工程的发展,轻量土体解决了一些以往工程难以解决的问题。轻量土体有以下几个特点:1)轻量土体具有较轻的容重,但其强度仍然保持较高的水平;2)轻量土体固化后自立性非常好,侧压力系数较小。若采用轻量土体代替普通回填土材料,可大大增加边坡稳定性,减少加固费用,并可以设计较少体积的支挡结构,增加工程经济性。本课题来源于河南省重点科技攻关项目“基于轻量土技术的淤泥再生材料应用研究(152102310082)和郑州市科技计划项目“EPS淤泥再生混合轻量土技术与应用研究(20130820)。本文以深圳龙岗某公路边坡为例,主要研究轻量土-支挡结构联体模型在陡坡回填路基中的模拟应用。基于理论计算、数值模拟等方法,对陡坡路基进行稳定性计算,分析轻量土-支挡结构联体模型与普通回填土对边坡稳定性及挡土墙的影响。本文的主要研究内容和结论有以下几个方面:(1)确定轻量土配方,获取参数。选取典型配方,进行轻量土试验,旨在获取轻量土体材料的弹性模量、重度、内摩擦角与黏聚力等物理力学表征参数。(2)基于理正边坡综合治理与有限元计算软件,对陡坡路基在无支护、普通回填土、轻量土-支挡结构三种状态下进行稳定性计算。三种状态下安全系数依次为1.41948、0.81605、1.316。理论计算结果表明:陡坡在原始状态下处于稳定状态,回填普通土后路基处于不稳定状态,换填为轻量土后陡坡恢复稳定状态。轻量土回填路基对于边坡稳定性有较大贡献。(3)基于Abaqus有限元计算软件,在普通回填土与轻量回填土两种工况下,选取9个典型点位,对陡坡土体位移、应力、应变进行分析。分析结果表明,回填路基换填为轻量土体后,土体应力应变数值整体小于普通回填土。在两种工况下,轻量回填土的应力与应变值都小于普通回填土,9个点位最大应力值相差20%,最大应变值相差22%。(4)通过Abaqus有限元计算软件,对挡土墙进行结构受力数值模拟计算,分析挡土墙墙体应力应变及挡土墙位移。挡土墙在普通回填土状态下最大应力为165kPa,轻量土状态下为133kPa。挡土墙墙后位移在工况一状态下为100.3mm,工况二状态下为13.7mm,挡土墙整体位移减小87mm。计算挡土墙抗滑移稳定系数及抗倾覆稳定系数,工况一状态下挡土墙抗滑稳定系数与抗倾覆稳定系数分别为1.45和2.51,工况二状态下挡土墙抗滑稳定系数与抗倾覆稳定系数分别为1.64和3.01。通过轻量土-支挡结构联体模型与普通回填土在陡坡回填路基中的对比应用研究,联体模型在工程应用中具有较高的经济性及安全性,值得推广应用。
[Abstract]:China has a vast territory and a large number of mountainous areas. The mountain has always been an important barrier to the development of economic traffic. Due to the influence of terrain, geomorphology, environment and investment, the problem of building fill subgrade on the steep slope is often encountered in the construction of highways. In the process of building backfill road base on steep slopes, because the ordinary backfill has high pressure shrinkage, With the characteristics of heavy self weight, the use of ordinary backfill as subgrade will bring great adverse effects on the stability of steep slope. With the development of backfilling subgrade engineering, light mass soil solves some problems which are difficult to solve in the past. The light weight soil has the following several characteristics: 1) light weight soil has light bulk density, but its strength remains high water 2) the light weight soil has a very good self-supporting and less side pressure coefficient after curing. If the lightweight soil is used instead of the ordinary backfill material, the stability of the slope can be greatly increased and the cost of reinforcement can be reduced, and the less volume of retaining structure can be designed to increase the engineering economy. This topic is based on the light quantity of key scientific and technological key projects in Henan province. Research on the application of soil technology for sludge regenerating materials (152102310082) and Zhengzhou science and technology project project "EPS silt regeneration mixed lightweight soil technology and Application Research (20130820). This paper takes a highway slope in Longgang, Shenzhen as an example, mainly to study the simulation application of lightweight soil and retaining structure model in steep slope backfill subgrade. Numerical simulation and other methods are used to calculate the stability of the steep slope subgrade, and analyze the influence of the lightweight soil - retaining structure model and the ordinary backfill soil on the slope stability and retaining wall. The main contents and conclusions of this paper are as follows: (1) determining the formula of lightweight soil and obtaining parameters. The physical and mechanical characterization parameters such as elastic modulus, severe, internal friction angle and cohesive force are obtained. (2) based on the comprehensive treatment and finite element calculation software of the slope, the stability of the steep slope subgrade is calculated under the three states of no support, ordinary backfill soil and light soil retaining structure. The safety coefficient in three states is in turn. The results of 1.41948,0.81605,1.316. theoretical calculation show that the steep slope is in a stable state in the original state, the subgrade is in the unstable state after backfilling the ordinary soil, and the steep slope is restored to stability after the replacement of the light soil. The lightweight soil backfill subgrade has great contribution to the slope stability. (3) based on the Abaqus finite element calculation software, it is used in the ordinary backfill soil and the soil. Under two conditions of light backfill, 9 typical points are selected to analyze the displacement, stress and strain of the steep slope. The results show that the stress and strain value of the soil is less than that of the ordinary backfill after the backfill subgrade is replaced by the lightweight soil. In the two conditions, the stress and strain value of the lightweight backfill soil are less than the ordinary backfill soil, 9 points. The difference of the maximum stress value is 20%, the difference of the maximum strain value is 22%. (4). Through the Abaqus finite element calculation software, the stress and strain of retaining wall wall and the displacement of retaining wall are analyzed by the numerical simulation of the retaining wall. The maximum stress of retaining wall in the ordinary backfill is 165kPa, and the displacement of the wall wall of the 133kPa. retaining wall under the light soil condition is the post displacement. Under the condition of one condition, 100.3mm and 13.7mm, the overall displacement of retaining wall is reduced by 87mm. to calculate the sliding stability coefficient of retaining wall and the anti overturning stability coefficient. The anti sliding stability coefficient and the anti overturning stability coefficient of retaining wall are 1.45 and 2.51 respectively under the condition of working condition, and the anti slip stability coefficient and anti dip coefficient and anti dumping coefficient of retaining wall under the condition of working condition two. The stability coefficient is 1.64 and 3.01., respectively, through comparison and application of light soil retaining structure model and ordinary backfill in steep slope backfill subgrade. The joint model has high economy and safety in engineering application. It is worth popularizing.
【学位授予单位】：河南工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U416.1

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