The conventional consolidated drained triaxial compression tests with three specimen dimensions were performed, and difference of the stress-strain behavior and shear strength between specimens at different sizes of a coarse-grained soil were investigated. The effect of specimen size on the behavior was studied. The test results showed that the stress-strain relation and the dilatancy for specimens with different size exhibit similar behavior, and the value is different. For the soil with the same cell pressure and gradation, the peak deviatoric stress of smaller specimen is higher than that of larger specimen, and the difference of the peak deviatoric stress decreases with the increase of specimen size. At lower cell pressure, variation of specimen size induces larger change of friction angle, and at higher pressure, the effect of specimen size on the angle becomes small. The Young’s modulus and bulk modulus also change with the specimen size, and the law is to be verified by more test results.
