Experimental Study On The Deformation Behavior And Constitutive Model Of Saturated Sands Subjected To Undrained Shear

It has been recognized that loose sandy-soils, such as residual soils, completely-decomposed granite (CDG) and completely-decomposed volcanic (CDV), usually display strain softening behavior while subjected to shearing under undrained condition.To well understand the deformation behavior of such soils is fundamental in rationally evaluating the failure mechanism of natural or fill slopes composed of sandy soils. Therefore, a series of triaxial shear tests are performed for Fujian standard sands and Coral sands in loose states. Based on the experimental results, deformation behavior of loose sands is systematically investigated. The inter-relationship among the peak strength, steady-state strength and confining pressure for representing the stress state and void ratio for describing the physical state are established.The critical-state soil mechanics theory and nonlinear model of stress and strain relation are combined together to develop an empirical model with a double-hyperbolic functions which can reproduce both nonlinear stress-strain behavior and steady-state behavior with strain softening of loose sands. The test data for Fujian standard sands and Coral sands are employed to define the parameters related to the proposed model. The rationality and validity of the proposed model is verified through the comparison of the predicted and measured data.