基于三剪统一强度理论的多晶冰软化本构模型研究及应用  

Research and Application of a Polycrystalline Ice Softening Constitutive Model Based on Triple-shear Unified Strength Theory

作　　者：张革 刘星炎 刘恩龙[4] ZHANG Ge;LIU Xingyan;LIU Enlong(Key Lab.of Geological Hazards on Three Gorges Reservoir Area,Ministry of Education,China Three Gorges Univ.,Yichang 443002,China;College of Civil Eng.&Architecture,China Three Gorges Univ.,Yichang 443002,China;College of Water Conservancy&Architectural Eng.,Shihezi Univ.,Shihezi 832000,China;College of Water Resources and Hydropower,Sichuan Univ.,Chengdu 610065,China)

机构地区：[1]三峡大学三峡库区地质灾害教育部重点实验室,湖北宜昌443002 [2]三峡大学土木与建筑学院,湖北宜昌443002 [3]石河子大学水利建筑工程学院,新疆石河子832000 [4]四川大学水利水电学院,四川成都610041

出　　处：《工程科学与技术》2024年第3期90-98,共9页Advanced Engineering Sciences

基　　金：国家自然科学基金(U22A20596);兵团青年科技创新人才科研启动基金(2023CB008-28);宜昌市自然科学研究项目(A23-2-007)。

摘　　要：随着全球气候变暖情况不断加剧,极地冰川正在加速退缩,冰川发生大规模崩塌、滑塌的频率逐渐增加。冰川冰的主要存在形式为多晶冰,开展多晶冰本构模型研究对于分析冰川稳定性具有重要的意义。本文基于三剪统一强度理论提出了能够反映中主应力影响的屈服函数和塑性势函数,考虑黏聚力随加载过程的变化规律,构建了基于等效塑性应变的硬化函数。采用非相关联流动法则建立能够反映多晶冰力学软化特性的弹塑性本构模型,利用多晶冰常规三轴剪切试验结果对提出的本构模型进行验证,结果表明,提出的弹塑性本构模型能够很好地描述多晶冰的偏差应力-轴向应变及体应变-轴向应变行为。随后,预测了不同中主应力系数条件下的多晶冰真三轴偏差应力-轴向应变及体应变-轴向应变行为。预测结果表明:多晶冰偏差应力-轴向应变曲线均表现出明显的软化,随着中主应力影响系数的增加,残余强度和峰值强度不断增加;体应变随着轴向应变的均表现出先体缩后体胀趋势,并且随着中主应力影响系数的增加,最大体缩量和最大体胀量不断增加。推导出多晶冰弹塑性本构模型的有限差分格式,并写入到数值软件Flac^(3d)中,利用单个单元对写入的本构模型的正确性进行了验证。研究结果旨在为冰川的稳定性评价提供理论及数值模拟基础。As global warming intensifies,mountain and polar glaciers are retreating at an accelerated pace.The frequency of large-scale glacier collapse and sliding is gradually increasing.Polycrystalline ice constitutes the primary form of glacial ice.The constitutive model of polycrystal-line ice holds significant importance for glacier stability analysis,mass balance,and multi-field coupling simulation.Drawing from the Triple-shear unified strength theory,we propose yield and plastic potential functions that can effectively account for the influence of principal stress.Considering the variation of cohesion throughout the loading process,we construct a hardening function based on equivalent plastic strain.An elastoplastic constitutive model with non-associated flow is established to capture the softening characteristics of polycrystalline ice.The validity of this model is confirmed through conventional triaxial compression tests of polycrystalline ice,demonstrating its ability to accurately describe axial strain-deviator stress and axial strain-volumetric strain behaviors.Subsequently,we predict the true triaxial axial strain-deviator stress and axial strain-volumetric strain behaviors of polycrystalline ice under different medium principal stress coefficients.Our predictions reveal signific-ant softening in the deviator stress-axial strain curves of polycrystalline ice,with both residual strength and peak strength increasing with the in-fluence coefficient of the medium principal stress.Volumetric strain exhibits an initial shrinkage followed by expansion with axial strain,with the maximum shrinkage and expansion increasing alongside the influence coefficient of the medium principal stress.Furthermore,we derive and in-corporate the finite difference scheme of the elastic-plastic constitutive model into Flac^(3d) numerical software,verifying its effectiveness through a single element simulation.In the context of global warming,these research findings are poised to offer a theoretical and numerical foundation for predictin

关 键 词：冰川稳定性 本构模型 多晶冰 数值模拟 

分 类 号：P343.6[天文地球—水文科学]