基于动态多步流动法的非饱和土水力特性测试研究

非饱和土水力特性在非饱和土的研究中起重要作用。鉴于传统的测试方法耗时较长,提出能够快速测定非饱和土水力特性的动态多步流动方法。该方法基于WeiDewoolkar提出的多孔介质热动力学混合物理论模型,推导出能够描述非平衡态的非饱和土饱和度的演化方程,通过对粉土和粉质黏土两种试样开展动态多步流动试验,并根据动态试验结果求解饱和度演化方程,得出试样处于平衡状态时的土水特征曲线和渗透函数。该方法不需要求解初边值问题,仅仅需要动态多步流动的试验数据求解饱和度的演化方程,进而得出试样的水力特性参数,与其它方法相比,该方法更加简单有效。

Dynamic multi-step outflow method for tests on hydraulic properties of unsaturated soils

Hydraulic properties of unsaturated soils play an important role in the studies on unsaturated soils. Because the traditional testing method takes a long time, a dynamic multi-step outflow method for fast determination of hydraulic characteristics of unsaturated soils is proposed. The method is based on the thermodynamic mixture of theoretical models proposed by Wei & Dewoolkar to derive saturation evolution equations to describe the non-equilibrium unsaturated soil by conducting two dynamic multi-step flow experiments on silt and silt clay samples. The dynamic evolution equations for saturation are soved according to the test results, and when the samples are in equilibrium state, the soil water characteristic curve and permeability function are obtained. This method does not solve the initial boundary values, just needs test data of dynamic multi-step outflow to solve the evolution equations for saturation, and thus hydraulic parameters of the samples are obtained. Compared with other methods, this method is more simple and effective.