基于Zienkiewicz-Pande屈服准则的弹塑性本构模型在FLAC3D中的二次开发及应用

Zienkiewicz-Pande屈服准则是Mohr-Coulomb准则的改进,在p-q子午面和π平面上都是光滑曲线,不存在尖点,不仅在数值迭代计算过程中易于处理,而且在一定程度上考虑了屈服曲线与静水压力的关系以及中主应力σ2对屈服的影响。该准则已应用于多个水电站地下洞室开挖支护计算中,但并未被大型数值计算软件所采用。根据弹塑性力学原理,详细推导了基于Zienkiewicz-Pande屈服准则的弹塑性本构模型在FLAC3D中的增量迭代计算格式;在FLAC3D提供的二次开发程序接口基础上,利用VC++程序语言实现了计算过程,并编译成动态链接库文件进行加载和调用。将自编的本构模型对一理想圆形隧洞进行模拟,计算结果与Mohr-Coulomb准则一致,验证了计算格式的正确性。将此本构模型应用于一大型地下洞室群的开挖围岩稳定分析中,得到的塑性区、位移场、应力场分布与Mohr-Coulomb准则计算结果分布规律相符,进一步验证了模型的适用性和可靠性。

Secondary development and application of an elastoplastic constitutive model based on Zienkiewicz-Pande yield criterion in FLAC3D

An elastoplastic constitutive model based on Zienkiewicz-Pande yield criterion is developed secondarily in FLAC3D and applied to stability analysis of surrounding rock during the process of excavation in a certain underground hydropower station. Zienkiewicz-Pande yield criterion is the one of forms of improved Mohr-Coulomb criterion，which is a smooth curve and has neither the singular vertex in the p-q plane nor the ridge corners in the π-plane. It is easy to handle not only in the numerical iterative calculation process, but also taking into account the relationship between yield curve and the hydrostatic pressure to some extent, as well as the impact role of the intermediate principal stress ? 2 on the yield surface. The criterion has been applied to calculation for excavation and supporting in several large-scale underground caverns of hydropower stations, but has not been adopted by any large numerical software. According to elastoplastic mechanics, incremental iterative calculation format of elastoplastic constitutive model on Zienkiewicz-Pande yield criterion is derived in detail. Based on the program interface of secondary development provided by FLAC3D, VC + + programming language is used to realize the calculation process and compile into dynamic-link library files loaded and invoked. In simulating to an ideal circular tunnel, the self-defined model is consistent with Mohr-Coulomb criterion to verify the correctness of the calculation format. Finally, this constitutive model is applied to stability analysis for excavated surrounding rock in large-scale underground caverns; and the distribution rules of calculated plastic zone, displacement field, stress field are accord with Mohr-Coulomb criterion, which validates the applicability and reliability of the model further.