基于硬化参量的盐岩蠕变疲劳本构模型  

Creep fatigue constitutive model of salt rock based on a hardening parameter

作　　者：范金洋[1,2] 唐璐宣 陈结[1,2] 杨镇宇[1,2] 姜德义 FAN Jin-yang;TANG Lu-xuan;CHEN Jie;YANG Zhen-yu;JIANG De-yi(State Key Laboratory for the Coal Mine Disaster Dynamics and Controls,Chongqing University,Chongqing 400044 China;School of Resources and Safety,Chongqing University,Chongqing 400044 China)

机构地区：[1]重庆大学煤矿灾害动力学与控制国家重点试验室,重庆400044 [2]重庆大学资源与安全学院,重庆400044

出　　处：《岩土力学》2023年第5期1271-1282,共12页Rock and Soil Mechanics

基　　金：国家自然科学基金项目(No.52274073,No.51834003);国家自然科学基金青年项目(No.51904039);重庆市研究生科研创新项目(No.CYB20023)。

摘　　要：盐岩具有较好的蠕变特性和损伤自恢复性,被公认为储能或油气储备的理想介质。对盐岩复杂力学行为进行准确表征和预测是保障盐穴地下空间利用工程安全性的基础。通过定义硬化参量等特征因子,建立了新的能够考虑复杂加卸载路径的盐岩蠕变疲劳本构模型。基于盐岩变形位错机制,引入双曲线阻尼元件,作为表征岩石硬化程度的状态变量;通过硬化参量的演化,考虑加卸载历史对盐岩变形行为的影响。借鉴经典Norton模型的应力-应变关系建立蠕变疲劳本构的基本框架关系。通过引入裂隙扩展因子,假设初始形核长度,考虑材料的断裂韧度,修正邻近破坏阶段(加速变形阶段)的应力-应变关系。该模型能够很好地预测常规蠕变、循环加卸载、下限间隔循环加卸载、梯形波蠕变循环加卸载等常见复杂加卸载路径下的塑性变形特征,且能够较好地表征恒荷载蠕变与循环加卸载之间的相互影响。新的蠕变疲劳本构模型中大部分参数具有较为明确物理意义,参数a表征盐岩稳态变形阶段应力与变形率的关系因子,参数b为确定盐岩第一阶段减速变形阶段的关系因子,参数d_(0)和μ_(d)分别表示初始裂纹形核量和裂隙扩展速率因子,共同修正模型临界破坏阶段的应力-应变关系。Salt rock has been recognized as an ideal medium for energy storage or oil and gas storage because of its good creep characteristics and self-healing.Accurate characterization and prediction of the complex mechanical behaviour of salt rock is the basis for ensuring the safety of the underground space utilization project of salt caverns.Based on proposed parameters of hardening and other characteristic factors,in this study,a new creep fatigue constitutive model is developed for salt rock considering complex loading and unloading path.Based on the dislocation mechanism of salt rock deformation,hyperbolic damping elements are introduced as state variables to characterize the degree of rock hardening.The influence of loading and unloading history on the deformation behavior of salt rock is considered according to the evolution of hardening parameters.Based on the stress-strain relation of the classical Norton model,a basic mathematical relation is established for the creep fatigue constitutive model.By assuming the initial nucleation length and considering the material fracture toughness,the stress-strain relation is modified for the range of adjacent failure stage(accelerated deformation stage)based on a newly introduced crack growth factor.In this manner,the proposed model can well predict the plastic deformation characteristics under complex loading and unloading paths such as conventional creep,cyclic loading and unloading,lower limit interval cyclic loading and unloading,trapezoidal wave creep cyclic loading and unloading.The model can also better characterize the interaction between constant load creep and cyclic loading and unloading.Most of the model parameters have clear physical meanings in the new developed creep fatigue constitutive model.Parameter a represents the relation factor between stress and deformation rate in the steady-state deformation stage of salt rock,parameter b determines the relation factor in the first stage of deceleration deformation stage of salt rock,and parameters of d_0 andμ_d r

关 键 词：盐岩 疲劳 蠕变 本构模型 

分 类 号：TU452[建筑科学—岩土工程]