An Improved Duncan-Chang Model Considering Effects of Intermediate Principal Stress and Shear Dilatancy

Abstract:

Duncan-Chang model is a nonlinear elastic model,which has been widely used in geotechnical engineering.For building on Mohr-Coulomb strength criterion and bulk strain assuming to be hyperbola in generalized Hooke’s law,Duncan-Chang model can not take the effects of intermediate principal stress and shear dilatancy into consideration.In order to reflect the effects of intermediate principal stress and shear dilatancy rationally,a new Duncan-Chang model is derived on the basis of unified strength theory and SHEN Zhujiang model.A novel parabolic bulk strain expression is adopted in the new model,and some forms of old parameter are improved.The modified model is validated with triaxial compression test results of coarse grained soil and clay.The results show that the new model can overcome the deficiency of the old Duncan-Chang model and reflect the effects of intermediate principal stress and shear dilatancy properly.

Key words:Duncan-Chang model; unified strength theory; intermediate principal stress; shear dilatancy