Abstract:

Free piston thin wall samplers were employed to obtain undisturbed specimens of natural sedimentary soils from ground surface to the depth of 30 m. One-dimensional consolidation compression tests performed on the undisturbed samples, and in-situ piezocone penetration test?CPTU, were adopted to investigate the physical and mechanical behavior of the Yangtze River backswamp soils. And then, intrinsic compression line (ICL) and intrinsic strength line (ISuL) of reconstituted clays were used as a basic frame of reference for describing the corresponding characteristics of natural sedimentary clays. The above results indicate that the Yangtze River backswamp soils have a high level of soil structure; consolidation coefficient Cv shows a rapid decrease after yielding and has obvious features of stages. Another conclusion could be drawn that the consolidation yield pressure and structural strength of natural sedimentary soils have more notable effects on engineering characteristics under lower static load level of the low embankment. Moreover, it's of practical value to decrease the construction disturbance of natural soil and make full use of the structural strength in engineering application.

Key words: structural characteristic, Yangtze River backswamp soft soil, low embankment, engineering effect