Modeling and analysis of reinforced granular layer overlaying very soft soil.

摘要

Many regions of lowlands contain areas of very soft soils where large settlements are observed. Placing a fill over these areas will lead to extensive differential settlements. For this reason, reclaiming such surfaces with the aid of reinforcements is very essential.;The proposed model is an elastic-plastic constitutive model derived from CANAsand model which uses a non-associated flow rule along with the concept of the state boundary surface possessing the critical and the compact state. The model is capable of simulating the surface profile of reinforced granular fill over very soft soil due to the immediate settlement. A primary ground deformation profile is evaluated prior to filling and is based on a parametric study involving variables such as the height and the spacing of the embankment fingers, the stiffness modulus of the reinforcement and the cohesion of the soft soil. The numerical results indicated that these parameters affect the performance of the system in many direct ways. The immediate and final settlement is based on the level the first deformation has attained and is estimated using a nonlinear and incremental stress-strain analysis. An integro-differential equation written in its finite difference form is developed to estimate the total displacement field of the system. The computer generated results showed that larger surface settlements were associated with high void ratios whereas smaller surface settlements were associated with low void ratios.