EXPERIMENTAL STUDY OF SWELLING CHARACTERISTICS OF WEAK EXPANSIVE SOIL

At present, the main soil swelling force measuring methods include swelling-consolidation method, pressure swelling method, balance pressure method, constant volume method. Based on the constant volume method of measuring soil swelling force, the TST-55-type permeameter, high-precision pressure sensors and data acquisition system are used to improves measuring method of soil swelling force, and to study the expansion characteristics of expansive soil. Test results show that the initial water content and dry density of soil sample have a significant influence to limit swelling force. The paper establishes the equation for their relation with limit swelling forces. At lower initial water content, when soil sample's limit swelling force of different dry density reaches a peak, it has a different rate of decrease. The value along with increasing of the dry density can be decreased. A linear relationship exists in the double logarithmic coordinate axis about the reduction value of limit swelling force and the dry density. At higher initial water content, when soil sample's limit swelling force of different dry density reaches a peak, it will remain stable trend. There is a good linear relationship between the logarithm of limit swelling force and initial water content. There is also a good linear relationship between the logarithm of water absorption of soil sample and initial water content or dry density.