裂隙花岗岩非线性蠕变本构模型及参数分析  

Nonlinear Creep Constitutive Model of Fractured Granite and Its Parameters Analysis

作　　者：王春萍[1,2,3] 刘建锋 陈亮[1,2] 刘健[1,2] 赵星光 马洪素[1,2] WANG Chunping;LIU Jianfeng;CHEN Liang;LIU Jian;ZHAO Xingguang;MA Hongsu(Beijing Research Inst.of Uranium Geology,Beijing 100029,China;CAEA Innovation Center for Geological Disposal of High-Level Radioactive Waste,Beijing 100029,China;College of Water Resource&Hydropower,Sichuan Univ.,Chengdu 610065,China)

机构地区：[1]核工业北京地质研究院,北京100029 [2]国家原子能机构高放废物地质处置创新中心,北京100029 [3]四川大学水利水电学院,四川成都610065

出　　处：《工程科学与技术》2024年第4期141-149,共9页Advanced Engineering Sciences

基　　金：核设施退役治理专项资助科研项目(科工二司[2020]194号);国家自然科学基金资助项目(42307258);四川省重点研发项目(2022YFSY0007)。

摘　　要：裂隙花岗岩的蠕变特性对高放废物地质处置库的长期稳定性和安全性至关重要。本文基于裂隙花岗岩在不同应力条件下的蠕变试验结果,结合蠕变过程中应力产生的损伤累积的影响,提出一种考虑损伤的弹黏塑性体。通过将经典Burgers模型的黏性元件替换为分数阶黏弹性元件,将黏弹性体替换为考虑损伤的弹黏塑性体的方法,构建了裂隙花岗岩非线性蠕变本构模型,并推导出模型在3维应力状态下的本构方程。通过对倾角30°及45°单裂隙花岗岩在不同应力条件下蠕变试验数据的拟合分析,确定了模型参数,验证了模型的适用性和合理性,获得了各模型参数随应力水平的变化规律。通过模型参数的敏感性分析,揭示了分数阶导数、损伤参数,以及应力水平对裂隙花岗岩蠕变应变的影响规律,并验证了裂隙花岗岩非线性蠕变本构模型在特殊条件下可退化为经典Burgers模型。研究表明,本文提出的裂隙花岗岩非线性蠕变本构模型能够准确地描述裂隙花岗岩蠕变破坏全过程的3个阶段,尤其是加速蠕变阶段应变随时间非线性增长的过程。The creep behavior of fractured granite is crucial for the long-term stability and safety of high-level radioactive waste disposal repositories.This study proposes a damaged elastic-visco-plastic model,considering the effect of stress-induced damage accumulation during the creep process.The model replaces the Newtonian element with a fractional derivative viscoelastic element and the classical viscoelastic body with a damaged elastic-visco-plastic body within the Burgers model framework.Consequently,a new nonlinear creep constitutive model and its corresponding 3D creep equation for fractured granite are established.The model parameters and their variations with stress levels are determined by fitting the experimental creep results of granite samples with fractures inclined at 30 and 45 degrees under varying stress conditions.Additionally,the suitability and rationality of the creep model are verified.A sensitivity study is conducted to examine the impacts of the fractional derivative order,damage factor,and stress level on the creep strain of fractured granite.The findings suggest that in specific cases,the nonlinear creep constitutive model can be simplified to the classical Burgers model.Importantly,the proposed model accurately describes the three stages of the creep failure process,particularly highlighting the nonlinear characteristics of creep strain in the accelerated stage.

关 键 词：裂隙花岗岩 蠕变 非线性模型 分数阶导数 参数分析 

分 类 号：TU451[建筑科学—岩土工程]