Experimental Study And Constitutive Modelling Of Shenzhen Natural Completed Decomposed Granite

Completed decomposed granite (CDG) is widely distributed in the Southern China area. It has great significance to study its physical and mechanical properties for city infrastructure construction. However, systematic research on the natural CDG is relatively less about properties and constitutive model because of limited condition. Through literature, experimental and theoretical research, physical and mechanical properties of CDG were thorough analyzed, and the constitutive model was put forward for numerical analysis.A series of comprehensive laboratory test were performed for high-quality natural sample and remolded sample, which were sampled in the Shenzhen Futian District. In addition, triaxial compression in both drained and undrained conditions were systemly done. Laboratory results showed that the natural granite had the strong structural property, whose initial strength and stiffness were larger than that of remolded sample. But the mechanical properties of natural sample tend to that of remolded one following structure damage.Using isotropic hardening rules from bounding surface model and non-associated flowing rules, the CDG constitutive model considered structural effect was given. Moreover, small strain model, as data interface model of elastoplastic constitutive model, was put forward on the basis of Small-Strain Overlay model and damage theory of structural soil. The mechanical properties in full strain field could be forecasted by the CDG constitutive model. Preliminary validation with experimental data and case study show that the model can effectively simulate the mechanics character of CDG.