粒状土与结构接触面多重剪切边界面模型

针对工程中存在大量的土与结构物相互作用,使接触面的力学特性对土体和结构物的受力变形及其相互作用产生重要影响的问题,利用塑性滑移理论,将粗粒土与结构接触面的宏观变形分解为一个宏观法向变形和剪切面内一系列不同方向分布的相互独立虚拟微观剪切变形；通过虚功原理,在粒状土的状态相关和边界面弹塑性理论框架内建立一个粗粒土与结构接触面的多重剪切边界面模型.每个微观剪切变形包含一个微观剪应力-应变关系和一个微观应力-剪胀关系.引入一个与接触面土体密度和法向应力相关的状态参数,用以描述不同状态下土与结构接触面的变形和强度特性.对不同粗粒土与结构接触面在二维或三维应力条件下的单调和循环剪切试验进行模拟计算,模型预测与试验结果吻合良好,说明模型能够合理地描述粗粒土与结构接触面的非线性力学行为.

A multi-shear bounding surface model for coarse granular soil-structure interfaces

There are a great number of soil-structure interaction problems during construction, and the mechanical characteristics of the interfaces may have significant effects on the forced deformation and interactions of soil-structure systems. Hence, following the slip theory of plasticity, the macro deformation of soil-structure interfaces was decomposed into a macro normal deformation and a series of orientated micro shear deformations associated with virtual micro shear structures in the shear plane. Based on the principle of virtual work, a multi-shear bounding surface model for coarse granular soil-structure interfaces was established in consideration of the states of coarse granular soil and within the framework of bounding surface elasto-plastic theory. Each micro shear response contains a stress-strain relation and a stress-dilatancy relation at a micro level. By introducing a state parameter dependent on soil density and normal stress, the model was used for characterizing the deformation and strength characteristics of soil-structure interfaces in different states. The effectiveness of the model was confirmed by simulating the available published interface tests between coarse granular soil and structure interfaces subjected to monotonic and cyclic loadings for two- and three-dimensional stress paths.