Experimental study on the evolution of the drained mechanical properties of soil subjected to internal erosion

Internal erosion can cause geotechnical structures to fail due to the loss of fine particles, which is induced by internal erosion that can weaken the mechanical properties of soil. Few studies have focused on the effect of internal erosion on the mechanical properties of soil. Accordingly, the present paper studies the evolution laws of the drained mechanical properties of soil due to internal erosion by conducting a series of triaxial consolidated drained shear tests and using the fine particle elimination method. The main conclusions of the study are as follows. Under the same confining pressure, the strain-softening phenomenon of the stress–strain curve will decrease with an increasing loss of fine particles, and a soil sample with a lower loss rate of fine particles will have a more dilative response. The loss of fine particles decreases the drained failure strength and drained internal friction angle. Mathematical relationships between the drained failure strength and the loss rate of fine particles and between the drained internal friction angle and the loss rate of fine particles have been established. A modified Duncan–Chang model that considers the loss of fine particles induced by internal erosion has been established.