含水弱化的软岩变参数蠕变损伤模型研究

Creep damage model with variable parameters and weakness effects by water of soft rock

为准确描述软岩受水弱化作用影响的蠕变特性,基于西原模型,引入与含水率有关的损伤变量Dω以及与时间相关的损伤变量Dt,建立了考虑软岩含水劣化效应的变参数蠕变本构模型,并采用参数反演的方法对模型的合理性和正确性进行了验证。研究表明:水的存在导致软岩蠕变量增加,到达稳定蠕变的时间延长;改进的蠕变损伤模型在不同含水状态和不同应力等级下的拟合曲线与试验曲线都十分吻合;该模型可以较好地描述蠕变全过程尤其是加速蠕变阶段。开展含水弱化软岩蠕变损伤本构关系的研究,将为进一步认识软岩的流变特性提供一定的理论依据。

To accurately describe creep characteristics of soft rock affected by water,the moisture-related variable Dωand time-related variable Dt were presented to establish the creep damage model with variable parameters of soft rock based on the viscoelastoplastic model.Rationality and correctness of this new model were identified by the parameter inversion method.It showed that water in the soft rock increases the creep displacement and extends the time to reach the stable creep stage.The inversion curves of the new model were highly coincident with the test curves under different moisture and stress conditions,indicating that this model could be used for describing the creep properties in whole process,especially at the third stage.The creep damage constitutive relation of soft rock under different moisture conditions provides a theoretical basis for the further understanding of the rheological properties of soft rock.