基于幂强化本构模型的轴对称圆巷弹塑性解

Elastoplastic solution of axisymmetric circular tunnel based on power-hardening model

轴对称圆巷的弹塑性求解的关键是选择合适的屈服准则。已经有诸多学者选择Mohr-Coulomb准则、Drucker-Prager准则和Hoek-Brown准则等,进行了相应的求解。为了探讨更符合工程实际需要的准则和求解,在考虑岩石材料的应变强化效应的条件下,建立了轴对称圆巷的幂强化本构模型和基于Drucker-Prager屈服准则的幂强化-理想塑性模型,并进行了弹塑性求解。以工程实例为计算条件,将幂强化-理想塑性模型的计算结果与基于Mohr-Coulomb准则、Drucker-Prager准则的理想塑性模型和幂强化模型的计算结果分别进行了对比,分析幂强化参数对围岩弹塑性解的影响。研究表明,应变强化效应对围岩稳定性有较大影响,对于应变强化效应较强的岩石材料,采用幂强化模型分析更接近工程实际。

A suitable yield criterion is the key to elastoplastic solution of axisymmetric circular tunnel. Many scholars observed corresponding solutions based on criteria of Mohr-Coulomb、Drucker-Prager and Hoek-Brown. The paper establishes powerhardening model, power hardening-perfectly plastic model based on Drucker-Prager failure criterion of axisymmetric circular tunnel; and acquires the elastoplastic solutions, taking strain-hardening effect into account during the calculation to meet the needs of practical engineering. For a project example, the paper compares the results of power hardening-perfectly plastic model based on Mohr-Coulomb failure criterion and Drucker-Prager failure criterion, and power-hardening model respectively. The influence of power-hardening index n on elastoplastic solutions of surrounding rock is analyzed. The study results show that the effect of strain-hardening is of great impact on the stability of surrounding rock, and it is of more practical value to adopt power-hardening model for the rock of great strain-hardening effect.