Consolidation deformability

Zhang Junhui, Miao Linchang, Huang Xiaoming. Study on secondary consolidation deformation of soft clay. Journal of Hydraulic Engineering, 2005, (1) 1-5 (In Chinese). 

The total settlement at top of a pile consists of the immediate settlement and the long-term settlement. The immediate settlement occurs during or shortly after the loads are applied, which includes elastic compression of the pile and deformation of the soil surrounding the pile under undrained loading conditions. The long-term settlement takes place during the period after the loads are applied, which includes creep deformation and consolidation deformation of the soil under drained loading conditions. 

In order for it to perform the reinforcement function, the geotextde must be allowed to deform to develop its strength. When stabilization of a site occurs, there is consolidation of the sod, and with this comes deformation of the geotextde. Due to the deformation of the geotextde, strength is required to ensure that a site fadure does not occur, ie, there can be a reinforcement component in the stabilization process. 

Granules remain wet and can deform and consolidate. The behavior of a granule is therefore a function of its history. 

Most authors who have studied the consolidation process of solids in compression use the basic model of a porous medium having point contacts which yield a general equation of the mass-and-momentum balances. This must be supplemented by a model describing filtration and deformation properties. Probably the best model to date (ca 1996) uses two parameters to define characteristic behavior of suspensions (9). This model can be potentially applied to sedimentation, thickening, cake filtration, and expression. 

Models of the intimate contact process that have appeared in the literature are commonly composed of three parts or submodels. The first submodel is used to describe the variation in the tow heights (surface waviness or roughness) across the width of the prepreg or towpreg. The second submodel, which is used to predict the elimination of spatial gaps and the establishment of intimate contact at the ply interfaces, relates the consolidation pressure to the rate of deformation of the resin impregnated fiber tow and resin flow at ply surface. Finally, the third submodel is the constitutive relationship for the resin or resin-saturated tow, which gives the shear viscosity as a function of temperature and shear rate. 

By closely examining the layout in Figure 7.7, a representative volume element can be selected for study, as shown in Figure 7.8. Region A, which comprises 25 percent of the area of the representative volume element, is in initial contact. When the consolidation pressure is applied, the deformation is initiated in region A, and the resin flows in the x-y plane to fill the gaps in regions B, C, and D. 

A theoretical model for intimate contact for in-situ consolidation has been developed in Reference 21. In this model, the irregular surface of the thermoplastic tow is modeled as a series of rectangular elements, oriented along the fiber axis, which are deformed as local pressure is applied (Fig. 13.11). The amount of flattening is quantified as the degree of intimate contact Dic (Eq. 13.14)... 

Lewis, R.W. and Schrefler, B.A. (1998) The Finite Element Method in the Static and Dynamic Deformation and Consolidation of Porous Media, 2nd ed., Wiley, Chichester... 

It was Wollaston (30) who in 1829 recognized the great pressures needed for compaction of dry powders—an observation that led to his famous toggle press. Since that time, compaction and deformation of powders and particulate systems have been extensively studied (31-35). There are many difficulties in analyzing the compaction process. Troublesome in particular are the facts that the properties of particulate solids vary greatly with consolidation, and that stress fields can be obtained, in principle, only in... 

Construction of the Dynamic Internal Yield Locus. The dynamic yield locus represents the steady state deformation, as opposed to the static yield locus which represents the incipient failure. The dynamic yield locus is constructed by plotting on a (a, t) plane the principal Mohr circles obtained for various consolidation stresses. The dynamic yield locus will be the curve or straight line tangent to all circles, as shown in Figure 17. The dynamic angle of internal friction S and cohesion C are independent of the consolidation stress. S and Q are obtained as the slope and the intercept at er=0 of the dynamic yield locus of the powder. 

---