桂林、柳州两种红黏土的土-水特征曲线

Soil-water characteristic curves of two kinds of lateritic clay from Guilin and Liuzhou

采用压力板法和滤纸法联合测定柳州、桂林两种红黏土的土-水特征曲线,发现同一含水率下桂林红黏土的基质吸力大于柳州红黏土,具有较强的持水能力。对相关试验结果的分析表明:(1)从物性指标比较,桂林红黏土具有较高的液、塑限及黏粒含量,黏性较高;(2)从矿物成分分析,桂林红黏土中的矿物含有三水铝石和针铁矿,且针铁矿含量为15.6%,是柳州红黏土的2倍,表明桂林红黏土处于更高的红土化水平,土中团粒化更为发育,形成利于持水的孔隙结构。最后,使用van Genuchten(V-G)模型对两种红黏土的土-水特征曲线进行拟合,结果表明V-G模型可用于两种红黏土的土-水特征曲线的拟合,且具有较高的相关度。

The pressure method and filter paper method are combined to determine the soil-water characteristic curves（ SWCC） of lateritic clay from Liuzhou and Guilin. The SWCC shows that the matrix suction of the Guilin lateritic clay under the same moisture content is higher than that of Liuzhou lateritic clay,and the Guilin lateritic clay has stronger water holding capacity. Relevant experiment results show that：（ 1） Through the comparison of the physical indexes,the Guilin lateritic clay contains higher liquid limit and plastic limit,and clay content,higher viscosity.（ 2） Through the mineral composition analysis,Guilin lateritic clay contains gibbsite and goethite. The proposition of goethite is 15. 6%,which is as twice as the lateritic clay of Liuzhou. It indicates that Guilin lateritic clay is at a higher level of laterization with more soil aggregate and forms the pore structure which is conducive to hold water. Finally,the van Genuchten（ V- G） model was used to fit the SWCC of Guilin lateritic clay and Liuzhou lateritic clay. The results show that V- G model is suitable for both of them and closely relevant to practical situation.