MICROSCOPIC STRUCTURE EVOLUTION PARAMETERS OF SOFT DREDGER FILL IN STAGE OF SAFE OPERATION HYPERPLASIA WITH PRECONSOLIDATION EFFECT

The soft dredger fill has the characteristic of large void ratio, strong compressibility and low strength. It is fine grain soil of high clay content. Although the short soil formation time, it has certain structure strength. Mechanical property of soil depends on soil's microstructure. In engineering practice, the structural strength of soil increases in the stage of safe operation because of the sustained pressure on the soft dredger fill that has ground treatment. To study the microscopic parameter evolution of soft dredger fill in the process of hyperplasia, the remoulded soil from Binhai New Area of Tianjin is used to be the test material of complete structural deterioration. The variation of grain and pore count, equivalent diameter and aspect ratio is analyzed quantitatively in the process of hyperplasia of structure strength with Scanning Electron Microscope. The result of tests shows that: in the process of hyperplasia of structure strength, the count of grain and pore and equivalent diameter decline, while aspect ratio of grain and pore, and equivalent diameter increase. The change is obvious at the beginning of the generation of structure strength. The longer consolidation time, the stronger constitutive property is. Deviator pressure and consolidation time have the same effect on the constitutive property of soil.