由土体级配近似确定土-水特征曲线的一种方法

A method for estimating soil-water characteristic curve from grain-size distribution

利用毛细管理论推导了特定粒径颗粒堆积物中毛细水的上升高度,据此建立了土体级配与非饱和土土-水特征曲线的联系,构造了一个近似确定土-水特征曲线的新的物理经验模型。对大部分土而言,模型中引入的修正参数ouR与吸力水头h在对数坐标下呈现明显的线性相关性,可以使用ouln R?aln(h/m)?b进行拟合;利用非饱和土数据库UNSODA中406种土样的测量数据(包括干燥过程的土-水特征曲线和级配曲线)对拟合参数a、b进行了参数分析,统计了a、b的分布规律;计算显示,a、b与级配和孔隙比无关,可能受矿物组成影响。利用提出的模型进行预测时,可以用矿物组成类似的土样试验结果计算a、b值以确定修正参数ouR,在资料缺乏时也可使用统计得到的a、b平均值。该模型为间接确定土-水特征曲线提供了思路。

A new empirical physical model is presented to estimate the soil-water characteristic curve approximately. The capillary theory is used to infer capillary water height in granular materials of a specific grain diameter. For most soils, the correction factbr Rou introduced in this model shows remarkable linear relationship with the suction water head h in logarithmic coordinates and their relationship can be expressed as lnRou = aln（h/m） ＋ b. Data of 406 soil samples from the unsaturated soil database UNSODA are used to analyze the fitting coefficients a and b. It is shown that they are affected by neither grain-size distribution nor void ratio, and they might be related to the mineral composition of soils. Predictions of the soil-water characteristic curve （SWCC） of a specific soil can be achieved using the grain-size distribution of the soil, and the parameters a and b can be calculated from some experimental results of soils with similar mineral compositions. The mean values of a and b calculated in this paper may also be an alternative in the absence of related data.