Study on the Mechanical Characteristics of Turfy Soil With Different Decomposition Degree and Organic Content Under CUAI Stress Path

Turfy soil is a kind of humus soil characterized by high organic content, high compressibility, high moisture content, low stability, high void ratio and low decomposition degree, which lead to complexities of the mechanical properties of turfy soil. Besides some general characteristics such as nonlinearity, elastic-plastic, anisotropy and rheology, the mechanical properties are also influenced by stress history, stress state, stress level and the stress path. In order to reveal the influences that decomposition degree and organic content impose on strength characteristics and stress-strain behavior of undisturbed turfy soil, stress-strain characteristics and volumetric strain changes of different decomposition degrees and organic contents under CUAI stress path (conventional stress path) were studied and discussed. The results showed that there were more clay particles in turfy soil when it had high decomposition degree but low organic content; the increasing interlocking and friction between soil particles enhanced the ability to resist deformation. But when the soil samples accompanied with high decomposition degree and high organic content, because of strong water absorption ability the organic particles, the void ratio of turfy soil increased, which reduced the ability to resist deformation and it could be inferred that organic particles produced some new relative displacements under the shearing load.