Abstract: 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 1.4 g/cm3 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 106 kPa. 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.

Key words: soil-water characteristic curve (SWCC), lateritic clay, pressure plate method, filter paper method, saturated salt solution method