考虑流变参数弱化综合影响的软岩蠕变损伤本构模型及其参数智能辨识

根据损伤的定义和软岩的蠕变破坏特点,提出反映应力水平和时间因素对弹性模量弱化综合影响的软岩蠕变损伤变量的一般表达式,推导并建立软岩蠕变损伤演化方程,探讨损伤变量随应力水平和时间的变化规律。以Burgers模型为基础,建立可考虑参数综合弱化的软岩蠕变损伤本构方程。修正后的Burgers蠕变损伤本构模型体现了参数随时间增长和应力水平增大的弱化现象,反映了岩石材料的损伤劣化过程。基于粒子群优化算法(PSO)具有迭代过程简单、能有效地收敛到全局最优解等优良特性,提出基于PSO的蠕变损伤本构模型参数智能辨识的方法和步骤。采用MATLAB软件,编制基于粒子群优化算法的参数辨识程序。以某深部软岩试样蠕变试验为例进行验证分析,结果表明采用考虑参数综合弱化的蠕变损伤本构模型具有较好的实用性。

Study on the creep damage constitutive model of soft rocks considering rheological softening and intelligent identification of the parameters

According to the definition of damage and the characteristics of creep damage of soft rocks,a general expression of the creep damage variables is proposed to reflect the synthetic influence on the elastic modulus softening by stress level and time.Based on these,the creep damage evolution of soft rocks is deduced,and the variation of the damage variables is discussed.Based on the Burgers model,creep damage constitutive model considering the synthetic softening of parameters is established.The modified Burgers model can reflect softening phenomenon of parameters with the increases of time and stress level.Taking advantage of Particle Swarm Optimization(PSO),the method and steps of intelligent identification of the parameters of creep damage constitutive model based on PSO are put forward.Using MATLAB,the program of parameters identification based on PSO is worked out.The check analysis is conducted by using creep test of soft rocks.