振动轮作用下土壤中的竖向应力分布研究

发布时间：2018-03-22 20:37

本文选题：单钢轮振动压路机　切入点：土壤压实　出处：《长安大学》2014年硕士论文　论文类型：学位论文

【摘要】：我国公路多为强基薄面的半刚性路面，路基的强度决定了路面的承载能力和使用寿命，基层压实度不足则容易导致路面沉陷等致命损伤，无法彻底修复，因此基层土壤的压实度是高承载力和长使用寿命的关键。单钢轮振动压路机作为基层土壤压实的主导设备，主要靠钢轮的自重和振动对土壤进行压实。本文以全液压双驱单钢轮振动压路机为试验样机，根据样机性能参数测试结果建立“振动轮—土壤”的Abaqus有限元模型，并采用试验研究与仿真分析相结合的方法对振动轮作用下土壤中的竖向应力分布进行研究。本文首先分析了土壤的组成和压实机理，介绍了不同的压实方法及各自的理论依据，并对土壤的弹性、粘性及塑性本构关系进行了分析。然后通过试验得出了试验土壤的最佳含水量及土壤干密度与土壤的弹性模量、内摩擦角、黏聚力之间的联系，分析了振动压路机以低频高幅、高频低幅两种振动工况压实土壤时的起步起振特性，并根据振动轮作用下土壤中竖向应力的测试结果，分析得出竖向应力由动态应力和静态应力两部分组成，其中静态应力大于动态应力，动态应力频率与钢轮振动频率相同，并且分析了土壤中竖向应力幅值随土壤深度的变化规律。最后根据Abaqus模型的仿真结果，，分析了钢轮静压以及振动压实时土壤中竖向应力在钢轮宽度方向上的分布，发现同深度时钢轮边缘下方土壤中的竖向应力值最大；分析了土壤表层应力达到最大值时土壤中竖向应力分布规律，发现了土壤阻尼导致的应力传播滞后效应；分析了钢轮振动频率对土壤中竖向应力幅值及竖向应力幅值随深度衰减率的影响，对土壤不同深度的频率响应进行了阐述，然后分析了名义振幅对土壤不同深度处竖向应力幅值的影响规律，为实际选择振动参数提供了数据依据。
[Abstract]:Most highways in our country are semi-rigid pavement with strong foundation and thin surface. The strength of roadbed determines the bearing capacity and service life of pavement, and the insufficient compaction of base can easily lead to fatal damage such as pavement subsidence and can not be repaired thoroughly. Therefore, the compaction of soil is the key to high bearing capacity and long service life. As the dominant equipment of soil compaction, single steel wheel vibratory roller compacts the soil mainly by the weight and vibration of steel wheel. In this paper, the full hydraulic double drive single steel wheel vibratory roller is used as the experimental prototype. The Abaqus finite element model of "vibratory wheel-soil" was established according to the test results of the performance parameters of the prototype. The vertical stress distribution in the soil under the action of the vibration wheel was studied by means of the combination of experimental research and simulation analysis. In this paper, the composition and compaction mechanism of soil are analyzed, the different compaction methods and their theoretical basis are introduced, and the elastic, viscous and plastic constitutive relations of soil are analyzed. Then the relationship between the optimum soil moisture content and soil dry density and the elastic modulus, internal friction angle and cohesion of the soil is obtained, and the vibration roller with high amplitude at low frequency is analyzed. Starting vibration characteristics of compacted soil under high frequency and low amplitude vibration conditions. According to the test results of vertical stress in soil under vibration wheel, it is concluded that vertical stress is composed of dynamic stress and static stress. The static stress is larger than the dynamic stress, and the frequency of dynamic stress is the same as the vibration frequency of steel wheel, and the variation of vertical stress amplitude with soil depth is analyzed. Finally, according to the simulation results of Abaqus model, the distribution of vertical stress in the width direction of steel wheel is analyzed in the static pressure and vibration pressure of steel wheel. It is found that the vertical stress in the soil under the edge of steel wheel is the largest at the same depth. The vertical stress distribution in the soil was analyzed when the soil surface stress reached the maximum value, and the hysteresis effect of soil damping was found. The effects of vibration frequency of steel wheel on the amplitude of vertical stress and the attenuation rate of amplitude of vertical stress with depth in soil are analyzed. The frequency response of soil at different depths is expounded. Then, the effect of nominal amplitude on vertical stress amplitude at different depth of soil is analyzed, which provides a data basis for the actual selection of vibration parameters.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U412.22;U415.521

【参考文献】