桂林红黏土的土-水特征曲线

Soil-water characteristic curve of Guilin lateritic clay

采用压力板法、滤纸法和饱和盐溶液法3种方法,对压实桂林红黏土进行全吸力范围内的土-水特性量测,研究干密度对于土-水特征曲线的影响。试验结果表明:干密度1.4 g/cm3的压实桂林红黏土的进气值约为20 k Pa;土-水特征曲线的过渡段与典型的土-水特征曲线不同,含水率或饱和度与吸力的对数坐标关系不是单一直线,而是出现了3段直线,并且中间一段平缓段下降斜率较小;当吸力增大到367 MPa时,含水率仅为0.74%,可认为如吸力继续增大至106 k Pa时,含水率和饱和度为0;用吸力与含水率关系表示土-水特征曲线时,吸力较大时不同干密度的曲线重合,认为干密度对土-水特征曲线无影响。用吸力与饱和度关系表示土-水特征曲线时,在吸力较小时,干密度越大,对应的土-水特征曲线越高;当吸力较大时,不同干密度的土-水特征曲线几乎重合。

In order to study the soil-water characteristic curve （SWCC） of Guilin lateritic clay in full suction range, three suction control or measurement methods are used： the pressure plate method, filter paper method and saturated salt solution method. Some tests are performed to study the influence of dry density on the SWCC. The result shows that the air entry value of compacted Guilin lateritic clay with dry density of i .4 g/cm^3 is about 20 kPa. The SWCC of Guilin lateritic clay is different from the typical SWCC. In the transition zone, there are three lines with different slopes and the slope of middle segment is small. When the suction increases to 367 MPa, the water content of the soil is only 0.74% .It can be inferred that the water content and saturation degree will decrease to zero if the suction increases to 106kPa. When the SWCC is expressed by the relation between suction and water content, the SWCCs with different dry densities coincide with each other in the high suction range, that means that the dry density has no influence on the SWCC. When the SWCC is expressed by the relation between suction and saturation degree, the SWCC with high dry density is higher than the smaller one in the lower suction range： When the suction is high, the SWCCs with different dry densities coincide with each other.