考虑残余强度影响的结构面与接触面剪切过程损伤模拟方法

岩土结构面和接触面剪切变形全过程的模拟是岩土结构设计与计算的重要依据。首先在深入探讨结构面和接触面剪切变形过程特征和剪切变形机理基础上,从结构面和接触面剪切单元微观受力入手,并将剪切单元抽象为未损伤和损伤两部分组成,其剪切荷载由这两部分共同承担,且损伤部分所受应力即为残余强度,建立出可以反映结构面和接触面破坏后仍具有残余强度特征的剪切损伤模型;然后,引进统计损伤理论,假定结构面和接触面剪切微元破坏服从Weibull分布,在探讨剪切微元强度度量方法基础上,建立出结构面和接触面剪切变形全过程的统计损伤演化模型,进而建立出模拟结构面和接触面剪切变形全过程的统计损伤本构模型。该模型不仅可以反映结构面和接触面应变软化特性,还可反映法向正应力的影响以及残余强度变形阶段特征;最后,通过实例分析并与同类模型进行比较,表明该模型的合理性与可行性。

Study of simulation method for the shear deformation of rock structural planes and interfaces with consideration of residual strength

Simulation of shear deformation of geotechnical structural planes and interfaces is important for design and calculation of geotechnical structures.Based on an analysis of the shear deformation characteristics and mechanism of structural planes and interfaces,a shear damage model reflecting the characteristics of residual strength after failure is established by analyzing the micro-mechanical shear element of the structural planes and interfaces.In this model,the shear element is divided into two parts: damaged material and undamaged material,the shear load is supported by the two parts together,and the damaged material provides bearing capability for residual strength.According to a comprehensive analysis method for shear element strength,a new statistical damage evolvement model is developed by introducing the statistical damage theory and assuming Weibull distribution for the strength of shear element.A new statistical damage constitutive model for simulating the shear deformation of structural planes and interfaces is established,which could not only well reflect the characteristics of strain-softening of structural planes and interfaces,but also describe the impact of normal stress and reflect the deformation characteristics of residual strength.The model is proven to be reasonable and feasible by comparison with experimental results and existing similar models.