Evaluation of soil structural characteristics of Taihu lacustrine-swamp natural sedimentary soils

The mechanical properties of natural sedimentary soils evidently differ from those of corresponding reconstituted clays due to the influence of soil structure. Using the intrinsic characteristics of reconstituted clays as a basic evaluation frame for describing the corresponding characteristics of natural sedimentary soils, the effect of soil structure on the compressibility of typical Taihu swamp natural sedimentary soils is assessed through comparative tests on the compressibility of undisturbed and reconstituted soil samples. The test results indicate that the structural yield stress arising from extra structural strength controls the deformation properties of natural intact soils, and the yield stress ratio may be regarded as a structural parameter to assess the influence of the natural soil structure. A simple evaluation system is described, which combines the stress sensitivity (S?) used to reflect the structural resistance of soil to the in-situ consolidation stress with the stability index accounting for the degree of metastability and yield stress ratio. This system enables the mechanical consequences of soil structure that controls the behavior of natural sediments to be quantitatively analyzed and evaluated. The analysis shows that Taihu lacustrine-swamp natural sedimentary soils are subjected to the effects of soil structure during their depositional and post-depositional processes and have a high level of sensitivity and strong structural resistance. Moreover, the result proves that the evaluation method is suitable for natural deposits with various soil structure.