Basic properties and microstructures of two typical silty clays collected along Beijing-Tianjin high-speed railway and Hangzhou metro line are studied. Using triaxial testing apparatus by GDS Company

static tests under consolidated undrained condition and dynamic tests under high cycles for simulating long-term traffic loading are carried out on these two soils. The undrained static strength

dynamic strength

critical dynamic stress ratio

development of accumulated dynamic strain

and shear strength after vibration of both soils have been studied for comparison. It is found that the soil along the Hangzhou metro line is with high water content

low density

large void ratio

which leads to weak strength and high sensitivity compared with those of Beijing-Tianjin’s. After small amplitude cyclic loading

both of the undisturbed specimens behave higher shear strength than that under static condition

while after large amplitude cyclic loading

vice versa. The remolded specimens always show a strength reduction after cyclic loading

no matter the amplitude of dynamic loading.