高庙子膨润土—砂混合物土水特征曲线数学模型研究

基于压力板法和水汽平衡法获取缓冲回填材料土水特征曲线,探讨干密度、掺砂率、温度和溶质浓度对缓冲回填材料土水特征曲线模型的影响。遴选出三参数的张虎元模型和四参数的Fredlund and Xing模型可用于拟合我国高庙子(GMZ)膨润土—砂混合物的土水特征曲线,发现吸力值测试范围对模型选取影响很大。干密度和温度与张虎元模型参数具有很好的相关性,而掺砂率和溶质浓度与模型参数的相关性不明显;干密度与Fredlund and Xing模型参数具有很好的相关性,但掺砂率、温度和溶质溶度与模型参数规律性不明显。根据试验数据拟合出的土水特征曲线模型参数与干密度的经验公式,可用来评估处置库运行期材料密度不断变化时的持水特性。

Mathematical model of soil-water characteristic curve for Gaomiaozi bentonite-sand mixture

The soil-water characteristic curves( SWCCs) of bentonite-sand mixtures were obtained using the pressure plate and vapor transfer technique. The influences of dry density,sand ratio,temperature and salt content on mathematical model of SWCCs are discussed. Zhang model with three parameters and Fredlund and Xing model with four parameters are better to fit the SWCCs of Gaomingzi bentonite-sand mixtures,and the suction also influence the final model parameters. For the Zhang model,there is a better correlation between model parameter and dry density,temperature,while the correlation is not obvious for the sand ratio and salt content. For Fredlund and Xing model,there is a better correlation between model parameter and dry density,while the model parameter is not obviously related with the sand ratio,temperature and salt content. The formula obtained from the experiment for the relationship between the model parameters and density could be applied to estimate the water holding capacity during the disposal operation period,as the dry density is always changing.