振动压实过程土体参数识别方法研究

Study on Identification of Soil Parameters in Vibrating Compaction

为了分析土壤特性与振动压路机在振动压实过程中的动态相互作用关系,提高压实效果,对振动压实过程中土壤刚度、阻尼、土体随振质量及土的固有频率等参数进行动态识别。用相似理论与模型试验法在确定了模型与原型之间的几何相似比并满足载荷相似条件后,根据模型试验结果推导出了原型土体参数;用方程对等法把受简谐激振力作用的振动轮等效为集中质量振动系统,以此作为振动压实过程的力学模型,根据振动微分方程的等效条件进行识别;用幅频特性曲线拟合法以振动压路机-土壤系统动力学方程为基础,用计算机进行动态仿真。分析表明:土的刚度和阻尼,不仅与被压实时土的初始状态、环境温度和湿度等因素有关,而且随振动压实过程中压实度的变化而改变。

To analyze the dynamic interplay of soil characteristics with working parameters of vibrating roller during vibrating compaction process and improve the compaction effect, dynamic identification of the soil parameters such as rigidity, damping, soil additional vibrating mass and natural frequency was conducted. When the geometric similitude ratio of the model to the prototype was determined and the loading similitude condition was satisfied by using similitude theory in structure modeling and experimental techniques, the prototype soil parameters were derived according to the model test result. The vibrating wheel compelled by harmonic exciting force was treated as a lumped mass vibrating system by equation equity method. By using this mechanical model in vibrating compaction, soil parameters were identified according to the equivalence of vibrating differential equation. The curve fitting method of amplitude versus frequency response was used for dynamic simulation based on the systematic dynamic equation of vibrating roller-soil system. Analytical result shows that the soil rigidity and damping were determined not only by the initial state of compaction, environmental temperature and humidity, hut also by the varying of compaction degree during vibrating compaction.