路基土变形机理试验及数值模拟研究

发布时间：2018-01-22 04:53

本文关键词： 路基数值模拟邓肯-张模型差异进化反分析渗流　出处：《大连海事大学》2014年硕士论文　论文类型：学位论文

【摘要】：交通运输业关系着国民经济命脉,它的进步与变革直接关系到生产力的发展与提高。作为运输系统中核心环节的公路,在基础设施建设中始终占据着重要地位。路基质量的好坏,直接影响到路面或轨道的使用质量,在其上部荷载的作用下,路基容易产生过量的残余变形,表现为较大的工后沉降、不均匀沉降并开裂,且逐步反应到路面。研究路基土的沉降机理,并建立路基沉降的计算模型对于保证路基质量,保障交通运输安全具有重要的作用。本文基于实际的路基工程背景,进行路基土变形规律研究。首先进行了实际工程中土样的土工试验,获得了土的基本物理性质指标和力学参数。通过试验研究了污染环境对水泥土的超声波速的影响规律。然后利用研发的差异进化和应力回映弹塑性FEM程序进行了所选路段进行了路基沉降计算以及力学参数的反分析计算,解决了路基土参数的不确定性问题。考虑地下水对路基土的影响机理,采用流固耦合模型进行路基土的数值模拟计算,分析渗流对与路基沉降的影响。最后考虑路基土应力应变的非线性特点,研究了路基土的邓肯张模型参数和计算方法,基于FLAC3D平台二次开发了邓肯张计算模型,模拟某路段路基沉降,分析各参数对路基沉降的不同影响。本论文的研究为进一步理解路基沉降机理和开展相关计算,提供了理论依据及有效途径,对类似的路基工程开展路基土变形规律的试验及数值模拟研究计算具有借鉴意义,结果和结论对于路基现场施工也具有积极的指导意义。
[Abstract]:Transportation industry is related to the lifeblood of the national economy, and its progress and transformation are directly related to the development and improvement of productive forces. The quality of roadbed has a direct impact on the quality of pavement or track. Under the action of upper load, the subgrade is prone to produce excessive residual deformation. It is shown as large post-construction settlement, uneven settlement and cracking, and gradually reflects to the pavement. The settlement mechanism of subgrade soil is studied, and the calculation model of subgrade settlement is established to ensure the quality of roadbed. Based on the background of the actual subgrade engineering, the deformation law of subgrade and soil is studied in this paper. First, the geotechnical test of soil sample in practical engineering is carried out. The basic physical properties and mechanical parameters of the soil were obtained. The influence of polluted environment on the ultrasonic velocity of cement soil was studied through experiments. Then the differential evolution and stress echo elastoplastic FEM program was developed. The subgrade settlement calculation and the back analysis calculation of mechanical parameters are carried out on the selected section. The uncertainty of subgrade soil parameters is solved. Considering the influence mechanism of groundwater on subgrade soil, the fluid-solid coupling model is used to simulate the roadbed soil. The influence of seepage on subgrade settlement is analyzed. Finally, considering the nonlinear characteristics of stress and strain of subgrade soil, the parameters and calculation method of Duncan-Chang model of subgrade soil are studied. Based on the FLAC3D platform, the Duncan-Chang calculation model is developed to simulate the subgrade settlement of a section of the road. This paper provides a theoretical basis and an effective way to further understand the mechanism of subgrade settlement and to carry out relevant calculation. It is useful for similar subgrade engineering to study and calculate the deformation law of subgrade and soil, and the results and conclusions are also helpful to the field construction of roadbed.
【学位授予单位】：大连海事大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U416.1

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