正常固结黏土的三维弹塑性本构模型

?应力空间内的非线性统一强度理论,与普通应力空间内的Drucker-Prager强度理论的形式相同。类比剑桥模型采用应力参量p和q的建模方法,在?应力空间内建立了土的三维弹塑性本构模型。首先提出了新的剪胀方程,结合正交条件,以p?,q?作为应力参量得到塑性势函数;其次模型建立过程中采用了修正剑桥模型的屈服面及非相关联流动法则;这种建模思路是一种新的直接建立三维弹塑性模型的方法。模型以岩土类材料的非线性统一强度理论为破坏条件,能够合理地反映岩土类材料的三维强度特性,较好地描述土体的变形特性,且能够退化为修正剑桥模型。

Three-dimensional elastoplastic constitutive model for normal consolidated clays

The nonlinear unified strength theory in β stress space is similar to the Drucker-Prager strength theory in principal stress space. Compared with the establishment of Cam-clay model with stress parameters of p and q, a new three-dimensional elastoplastic constitutive model is established in β stress space. A new dilatancy equation is proposed, and then plastic potential function is obtained combined with the orthogonality condition. The new model is based on the nonassociated flow rule and yield function of modified Cam-clay model. It is a new idea to establish three-dimensional elastoplastic constitutive model directly. The proposed model in which the failure condition is based on nonlinear unified strength theory can reflect the deformation and strength characteristics of soils reasonably, and can be devolved into the Cam-clay model.