Abstract: A free piston thin wall sampler was used to obtain undisturbed specimens of natural sedimentary silty soils from ground surface to the depth of 70 m.A series of tests were performed on both the undisturbed and the remolded/reconstituted samples.The difference in physical and mechanical behavior between clayey and silty soils was discussed.The void index could be used for normalizing the compressive curves of various remolded/reconstituted silty soils,and the normalized curve of void index versus applied stress for remolded/reconstituted silty soils lying below the A-line was consistent with the intrinsic compression line proposed by Burland based on clayey soils lying above the A-line.But the curve of natural silty soils lay above the sedimentation compression line in terms of the in-situ void index versus effective overburden pressure.The sedimentation compression line was proposed for natural ordinary clayey soils with a normally consolidated history.The above results indicate that natural silty soils are more easily disturbed during sampling and handling than ordinary natural clayey soils due to high sensitivity.