基于损伤模型的混凝土冻融循环过程数值模拟研究  

Numerical simulation of freeze-thaw cycling process of concrete based on damage model

作　　者：孟智田 李宗利[1,2] MENG Zhitian;LI Zongli(College of Water Resources and Architectural Engineering,Northwest A&F University,Yangling 712100,China;Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas of Ministry of Education,Northwest A&F University,Yangling 712100,China)

机构地区：[1]西北农林科技大学水利与建筑工程学院,陕西杨凌712100 [2]西北农林科技大学旱区农业水土工程教育部重点实验室,陕西杨凌712100

出　　处：《水资源与水工程学报》2024年第4期136-143,152,共9页Journal of Water Resources and Water Engineering

基　　金：国家重点研发计划项目(2017YFC0405101)。

摘　　要：冻融损伤是寒区混凝土主要破坏方式之一,冻融过程是混凝土材料逐渐破坏演变的过程。引入损伤理论建立了混凝土水热力损伤耦合模型,该模型可以模拟混凝土冻融过程中水的相变、孔隙水压等变化过程,通过累积损伤真实反映破坏过程。通过与相关文献中的试验数据对比,验证了模型的准确性,并研究了中心最低温度、降温速率以及初始孔隙率对混凝土试件冻融损伤的影响规律。结果表明:随着试件中心最低温度的降低、降温速率的增大和初始孔隙率的增大,混凝土的累积损伤值逐渐增大;损伤区虽然从混凝土试件四周逐渐向内发展,但在降温速率和初始孔隙率过大时,最大损伤区和裂缝却出现在棱角附近的试样内部,并向外部扩展,该结果解释了棱柱体混凝土冻融破坏后棱角最先掉落的现象。Freezing and thawing damage is one of the main damage modes of concrete in cold regions,and the process of freezing and thawing is a gradual destruction and evolution process of concrete materials.A hydrothermal damage coupling model of concrete was established based on the concrete damage theory.This model can simulate water phase change and pore water pressure variation in the process of freezing and thawing of concrete,and reflect the actual damage process by the index of cumulative damage.According to the comparison with available experimental data in the literature,the accuracy of this model was verified.Meanwhile,the influence of the center minimum temperature,cooling rate and initial porosity on the freeze-thaw damage of concrete were also investigated.The results show that the cumulative damage of concrete gradually increases with the decrease of the minimum temperature at the center of the specimen,and the increase of the cooling rate and the initial porosity.Although the damage zone gradually develops inward from the perimeter of the specimen,the maximum damage zone and cracks appear inside the specimens near the prismatic corners and expands to the outside when the cooling rate and initial porosity are overly large.This result explains the phenomenon that the corners are the first to fall off after freeze-thaw damage of prismatic specimens.

关 键 词：混凝土 冻融循环 水热力耦合模型 损伤 有限元模拟 

分 类 号：TV431[水利工程—水工结构工程]