Abstract: The shear strength characteristics of earth-rock material from river dredging obtained from different test methods are examined via large-scale indoor triaxial shear test and direct shear test. The earth-rock material from river dredging in the harnessing project of a small and medium-sized river in Shaoguan, Guangdong Province is taken as a case study. The results of large-scale triaxial shear test show that the shear strength of the earth-rock material from river dredging increases with the rising of strain and confining pressure, displaying weak hardening with no obvious peak strength. The results of large-scale direct shear test show that peak strength of the earth-rock material from river dredging exists under different vertical pressures, characterized by a weak strain softening. Comparison of shear strength parameters among different test methods implies that the shear strength parameters obtained from large-scale triaxial shear test is the largest, followed by those of conventional direct shear test and piled ring shear test in sequence. The research results prove that the earth-rock material from river dredging is of good shear strength, hence can be used as good embankment material after anti-seepage treatment.

Key words: earth-rock materials from river dredging, embankment, shear strength parameters, large-scale triaxial shear test, large-scale direct shear test, governance of small and medium-sized rivers