动载式水田土壤流变仪的研制

以四元件Burgers模型作为水田土壤的通用流变模型，通过将随时间随机增长的压力简化为时间的阶梯函数导出了动载条件下水田土壤的压力一下陷量一时间曲线，并提出了据此曲线用最优化理论计算土壤流变参数的方法；在此基础上，研制了一种基于虚拟仪器原理的动载式水田土壤流变仪。该种仪器可自动完成测量数据的采集、贮存及流变参数的计算。试验表明，该仪器所测的土壤流变参数与据静载下土壤的蠕变曲线计算的流变参数数值基本一致。

Development of Rheometer for Paddy Soils under Dynamic Loading

In order to study the influences of mechanical properties of paddy soils and other wet-soft soils on vehicle performance, and to provide the scientific basis for design and selection of vehicles and other machinery working on such soils, the approach and instrumentation were developed to measure the paddy soil rheological parameters under dynamic loading. The four-element Burgers model was used as the general rheological model of paddy soils in South China, the pressure-sinkage-time equation of the soil surface under dynamic loading were theologically developed by means of transforming the dynamic loading to a step function of time approximately, and an optimum method was used to calculate the rheological parameters according to the equation. Based on above, a kind of rheometer was develoed, by which data measuring and storing and rheological parameter calculating could be done automatically. The experiments carried out under both static loading conditions and dynamic loading conditions show that there is no significant difference between the rheological parameter values of soils measured with the rheometer and those calculated with the creep curve of soils under static loading.