考虑围压影响的岩石弹脆塑力学模型

Elastic-brittle-plastic mechanical model for rock with confining pressure

为模拟围压对岩石峰后强度、模量退化和剪胀的影响,将岩石的变形过程简化为线弹性变形、脆性跌落和理想塑性3个阶段,利用退化指数和扩容指数描述围压对岩石峰后强度、模量退化和剪胀的影响,建立了考虑围压影响的岩石弹脆塑力学模型。通过Hoek-Brown和Mohr-Column准则之间参数的转换关系,给出了模型峰后力学参数的确定方法。在FLAC软件下,利用Fish函数方法实现了建立的弹脆塑性力学模型。在数值算例中,利用本文模型分析了不同围压下岩石的峰后力学特性劣化和剪胀扩容特征,结果表明本文模型不仅能较好地模拟岩石峰前、峰后全程变形发展过程,而且能较好地考虑围压对岩石峰后力学特性的影响。

To model effects of confining pressure on the post-peak mechanical properties for rock such as the degradation of strength and modulus, and dilatancy, the deformation process is simplified into three phases including linear-elastic, brittle degradation and perfect plasticity. Degradation index and dilatancy index are employed to reflect the effects of confining pressure on the peak-post mechanical properties for rock in this paper, and an elastic-brittle-plastic model with confining pressure is presented. Based on the transformation relationship between Hoek-Brown failure criterion and Mohr-Column failure criterion, how to obtain the calculation parameters of the peak-post mechanical model in this paper is presented. The Fish function method within FLAC is adopted to realize the elastic-brittle-plastic mechanical model model in this paper. In numerical case study the peak-post mechanical properties of rock under varied confining pressure including the degradation of strength and modulus, and dilatancy are modelled. The results show that the model can perfectly describe the deformation process and the effects of confining pressure on peak-post mechanical properties of rock.