水化-冻融耦合条件下大理岩蠕变损伤本构模型

Creep Damage Constitutive Model of Marble Under Hydration Freeze-Thaw Coupling

为描述岩石在水化-冻融耦合条件下的蠕变特性,以大理岩为试验对象,分别开展酸性、碱性、中性溶液与不同冻融循环条件下的单轴压缩蠕变及核磁共振试验,分析T 2(弛豫时间)谱分布和蠕变试验结果,并进行耦合损伤演化,得到一个新的考虑水化-冻融与应力耦合的蠕变损伤本构模型。结果表明:1)大理岩T 2谱表现为三个谱峰,岩石以大孔径孔隙为主。2)冻融循环作用促进大理岩孔隙发育,不同溶液环境对孔隙发育影响从大到小的关系为酸性、碱性、中性。3)分别构建水化-冻融和受荷损伤变量,从而建立耦合损伤变量。基于大理岩蠕变特性,确定蠕变基础模型,进行耦合损伤演化,得到新的水化-冻融耦合条件下的大理岩蠕变损伤本构模型。4)新建模型模拟大理岩三种溶液冻融循环50次的的平均R^(2)达0.9854,远高于基础模型平均R^(2)(0.9194),说明本文新建模型对三种岩石蠕变数据辨识效果更好。

To describe the creep characteristics of rocks under hydration freeze-thaw coupling conditions,uniaxial compression creep and nuclear magnetic resonance tests were conducted on marble under acidic,alkaline,neutral solutions and different freeze-thaw cycle conditions.T 2 spectrum distribution and creep test results were analyzed,and coupled damage evolution was carried out.Finally,a new creep damage constitutive model considering the coupling of hydration freeze-thaw and stress was obtained.The results show that:1)The T 2 spectrum of marble exhibits three peaks,and pore in the rock is mainly composed of large size pores.2)The freeze-thaw cycle promotes the development of pores in marble,and the influence degree of different solution environments on pore development from high to lower is acidic,alkaline,and neutral.3)The hydration freeze-thaw and load damage variables were constructed to establish a new creep damage constitutive model of marble under the coupling conditions of hydration freeze-thaw.4)The average R^(2)of 50 freeze-thaw cycles of three different solutions of marble simulated by a new model is 0.9854,while the average R^(2)of the basic model is only 0.9194.