蛇纹大理岩蠕变规律及非线性蠕变模型研究

Study on Creep Law and Nonlinear Creep Model of Serpentine Marble

以杨林隧道工程为背景,对二衬开裂段蛇纹大理岩进行了40 d的分级加载单轴蠕变试验。结果表明,蛇纹大理岩在不同应力条件下的稳态蠕变速率和相应的蠕变应变规律与应力和时间的增加呈正相关。采用等时应力应变曲线拐点法测定蛇纹大理岩的长期强度为30 MPa。利用变阶分数阶微积分将损伤变量引入粘弹性和粘塑性过程,得到了一种新的弹粘塑性蠕变模型。新的弹粘塑性蠕变模型能够很好地描述蛇纹大理岩的三阶段蠕变过程,此模型相较传统西原模型,克服了无法对加速蠕变阶段很好描述的缺点,模型数量少,组合简单,可用于描述岩石蠕变过程的变形规律。

Based on the Yanglin Tunnel,a 40 day uniaxial creep test of serpentine marble in the cracked section of the second lining was carried out.The results show that the steady creep rate and the corresponding creep strain law of serpentine marble under different stress conditions are positively correlated with the increase of stress and time.The long-term strength of serpentine marble measured by isochronous stress-strain curve inflection point method is 30 MPa.In this paper,the damage variable is introduced into viscoelastic and viscoplastic processes by using variable order fractional calculus,and a new elasto-viscoplastic creep constitutive model is obtained.The new elastic viscoplastic creep model can well describe the three-stage creep process of serpentine marble.Compared with the traditional Nishihara Model,this model overcomes the disadvantage that it cannot well describe the accelerated creep stage.The number of models is small and the combination is simple.It can be used to describe the deformation law of rock creep process.