Soil deformation due to suffusion and its consequences on undrained behavior under various confining pressures

Suffusion, defined as the phenomenon whereby the fines gradually migrate through the voids of coarse fractions in a soil, has been widely detected in natural deposits and artificial earth structures. The occurrence of suffusion may chronically loosen the soil structure, increasing the vulnerability against large deformation and soil failure. In this paper, experimental studies on volume change of saturated gap-graded cohesionless soil during suffusion and its mechanical influence on undrained behavior are presented. Test results reveal that because of the loss of large amounts of fines during suffusion, volume of tested soil decreases and void ratio increases. Correspondingly, a distinctive undrained behavior of suffusional soil is noted from that of the reference soil without suffusion.