Overconsolidated Cohesive Soils Structural Model Of Binary Medium

On the basis of comprehensively analyzing the soil mass structure and the present state of soil mass structure model, the affection of cohesive soil's structural character to engineering character and the structure model of cohesive soil are studied in this thesis basing on the geotechnical breakage theory and by the way the existing problems in them are defined.Under the premise of the existing of soil structural character, the affection of cohesive soil structural character to its structural strength and the structural strength increment are analyzed. The structural character and the engineering character are analyzed by contrasting typical soft clay with worse structural stability to model red clay with better structural stability. Aiming at the cohesive soil's over-consolidation nature duo to the environment's deposition, the structural character of cohesive soil and the affection of it to engineering character are analyzed from the soil's shear characteristic, consolidation characteristic, compression characteristic, hole pressure, permeating characteristic and so on.On the basis of the existing of cohesive soil structural characteristic and its important influence to engineering character, according to the geotechnical breakage theory and over-consolidation characteristic of cohesive soil, the over-consolidation cohesive soil can be divided as structural lump and structural band in which the total stress acting on the cohesive soil can be described as cemented stress acting on structural lump and the frictional stress on structural band which value are shared according to the stress sharing principle by means of breakage parameter. The cemented stress of the structural lump is decided by the relationships of cemented stress-strain established by cohesive soil over-consolidation and generalized hooke's law by means of over-consolidation ratio in which the non-linearity and the ball brittleness, compression-rebound relations of over-consolidated soil are considered. Simultaneously, the frictional stress of the structural band is calculated by fictional stress-strain relationships by means of breakage parameters, established in terms of that after completely damages, the over-consolidated soil forms a structural band similarity to that of normally consolidated clay, in which the ball component of frictional stress is determined by stress-strain relationships of normal consolidated cohesive soil and the deviator component determined by the normalized union stress-strain relationships. Finally, according to the stress sharing principle and model hypothesis, a binary-medium structural model with the consideration of cohesive soil consolidation characteristic is established and the model algorithm is carried out according to the common sharing principle in which 11 model parameters, that can be determined by triaxial tests and the side limit compressive tests, are contained.Similarly, basing on the common sharing principle of the geotechnical breakage theories, the cohesive soil permeability coefficient can be divided as structural lump component and structural band component which can be shared by means of the breakage parameter. Importing the volume breakage rate and the local hydraulic gradient coefficient, a cohesive soil binary-medium influent model is established based on the Darcy's law and the sharing principle of permeability coefficient indexed by the mean velocity of stream and the average hydraulic gradient of structural lump and the structural band in which 3 model parameters, that can be determined by the permeability tests and the side limit compressive tests, are contained.