基于Drucker-Prager模型的振动压实有限元分析及试验研究

FEM Analysis and Experimental Research of Vibration Compaction Based on Drucker-Prager Model

为了研究振动压路机压实特性及振动轮与土壤动态响应关系,利用ABAQUS建立了"振动轮-土壤"有限元模型,讨论了Mohr-Coulomb模型和线性Drucker-Prager模型间的关系及适用条件,分析了振动轮下土壤应力分布特性及土壤参数对振动轮动态响应的影响,并对模型进行了试验验证。结果表明:当摩擦角≤22°时,土体单元应当用Drucker-Prager模型;当摩擦角>22°时,土体单元应当用Mohr-Coulomb模型。土壤的竖向应力沿着振动轮轴向呈对称分布,在振动轮行进方向沿着前进方向偏移,且竖向应力随着土壤深度的增加而快速降低。在振动压路机合理工况内,保持工作参数不变,振动压路机振动轮垂直加速度有效值随着压实遍数增加,模型基本正确,得到了压实度与加速度有效值的回归方程,为新型压实度监测系统提供了思路。

In order to further study the compaction characteristics of vibratory wheel and the dynamic response relationship between vibratory wheel and soil,the finite element model of“vibratory wheel-soil”was established by ABAQUS.The relationship and the applicable conditions between Mohr-Coulomb model and linear Drucker-Prager model were discussed.The distribution characteristics of soil stress under vibratory wheel and the influence of soil parameters on the dynamic response of vibratory wheel were analyzed,and the model was tested and verified.The results show that:Drucker-Prager model is more suitable for modeling the soil unit,when the friction angle is less than 22°.When the friction angle is more than 22°,the Mohr-Coulomb model should be used to model the soil.The vertical stress of soil is symmetrically distributed along the axis of vibratory wheel,and shifts along the forward direction of vibratory wheel.The vertical stress of soil decreases sharply with the increase of depth of soil.Under the reasonable working conditions of the vibratory roller,with the working parameters unchanged,the effective value of the vertical acceleration of the vibrating wheel of a vibrating roller increases with the number of compaction cycles.The proposed model is basically correct,and the regression equation between the compaction degree and the effective value of acceleration is obtained,which provides the idea for the new compaction degree monitoring system.