Measurement and Application of Suction in Unsaturated Soils

This paper summarizes the main development of suction measurement technology such as TDR, granular matrix sensor and capacity suction meter, analyses the influences of water content, dry density and structure of soil on soil-water characteristics curve (SWCC), gives the measurement method of SWCC using tensiometer and thermal conductive sensor and observation of matric suction in slopes of expansive soils by writers. The measurements of suction have been successfully used in evaluation of stability of soil slope and sampling disturbance, control of quality of rolled fill soil, prediction of rebound modulus of subgrade, analysis of the behavior of pile under fluctuated ground water table. The measurement technologies of suction should be improved, the results of observations and applications should be accumulated and the engineering methods to keep and enhance the suction should be researched.