Steady-State Behavior And Strength Properties Of Silty Soil In Yellow River Delta

The subsoil in the Yellow River Delta is a kind of silty soil that tends to liquefy and is sharply different from common soil. In this paper, from the perspective of stable theory, a series of consolidated and undrained triaxial compression tests (CU) were carried out on soil samples of various dry density and clay content to study the stable prosperities and strength characteristics of the silty soil of the Yellow River Estuary. The research contents include following aspects:(1) In this paper,a series of consolidated and undrained triaxial compression tests (CU) were carried out on soil samples of various dry density to study strain types ;the stable prosperities and strength characteristics of the silty soil of the Yellow River Estuary.(2) A series of consolidated and undrained triaxial compression tests (CU) were carried out on soil samples of various clay content to study the strength characteristics of the loose silty soil of the Yellow River Estuary; variability of the the stable lines and the internal frictional angle with the clay content; the relation between stable strength and vary initial consolidation and clay content.Conclusions were drawn as follows: Two strain types were observed during the course of CU: (a) when the soil is comparatively loose, strain softening was observed, at this state, it was most likely that flowing slide failure would occur in the soil sample. (b) when the soil is comparatively loose, shear swelling was observed, and the soil exhibited the property of strain hardening; at this state, flowing slide failure would never occur in the soil sample. Internal frictional angle of peak strength and residual strength increased with the increasing of dry density and decreased with clay content; the internal frictional angle of residual strength at various dry density was always larger than that of peak strength. In the ec-p,ss space and ec-qss, the stable lines of soil samples of various clay content paralleled with each others, the stable line varies with the clay content . At the stable state, the internal frictional angle decreased in small variation amplitude with the increasing of clay content. When the soil was loose, the stable strength could be expressed with the initial consolidation and clay content.