A new triaxial apparatus for high total suction using relative humidity control

The shear strength theory for unsaturated soils has been widely accepted in geotechnical engineering. The analysis of shear strength, volume change and seepage involving unsaturated soil requires the soil-water characteristic curve as key soil information. Several models have been proposed using a soil-water characteristic curve based on the experimental research. The procedures proposed are approximate but are satisfactory for analyzing many unsaturated soil mechanics problems. These functions have been tested for matric suctions below residual suction (i.e., below about 1500 kPa). This study presents triaxial compression test results for a desiccated soil subjected to high soil suction using a new unsaturated soil triaxial compression apparatus. Consequently, shrinkage of unsaturated soil proceeds due to applying high soil suctions, and the slope of failure envelope to the net normal stress is similar to that of a saturated soil or an unsaturated soil with low matric suction.