高温作用下混凝土热-水-力耦合损伤分析模型

以混合物理论为基础建立了高温作用下混凝土的热-水-力耦合损伤分析模型．将混凝土视为由固体骨架、液态水、水蒸气、干燥气体和溶解气体共5种组分构成的混合物，模型的宏观平衡方程包括各组分的质量守恒方程、整体的能量守恒方程及动量守恒方程，模型所需的状态方程及本构关系全部给出，最后给出基于4个主要参数（固体骨架位移、气压力、毛细压力和温度）的控制方程．模型考虑了混凝土在高温作用下，水分的蒸发与冷凝、胶结材料的水化及脱水、溶解气的溶解与挥发等相变过程；从材料变形破坏过程中能量耗散特征入手，基于Lemaitre应变等价性假说和能量守恒原理得到力学损伤演化方程，并考虑了高温引起的热损伤对材料力学性能及力学损伤演化规律的影响，建立了热-力耦合损伤本构模型．

A Coupled Thermo-Hygro-Mechanical Damage Model for Concrete Subjected to High Temperatures

Based on theory of mixtures,a coupled thermo-hygro-mechanical damage model for concrete subjected to high temperatures was presented.Concrete was considered as a mixture composed of solid skeleton,liquid water,water vapor,dry air and dissolved air.The Macroscopic balance equations of the model consisted of the mass conservation equations of each component,the momentum and energy conservation equation of the whole medium mixture.The state equations and constitutive model used in the model were given.Four final governing equations were given in term of four primary variables,i.e.displacement components of soil skeleton,gas pressure,capillary pressure and temperature.The processes involved in the coupled model included evaporation,dehydration,heat and mass transfer,etc.Through the process of deformation failure and energy properties,mechanics damage evolution equations were established based on the principle of conversation of energy and Lemaitre equivalent strain assumption,and then the influence of thermal damage on mechanical property and mechanics damage evolution equations were considered.