混凝土热-水-化-干湿应变多场耦合模型

Thermo-hygro-chemical-dry-wet strain multi-field coupled model of concrete

为了准确研究水工混凝土在服役环境中因湿度变化引起的应变应力特性,从基本理论出发,建立修正的热-水-化-干湿应变(THCD)多场耦合模型.在已有模型的基础上,引入优化的化学亲和力函数和吸附等温线方程,实现对水化过程和湿度多阶段演变的准确模拟,进一步建立湿度和应变之间的关系,使模型可以对湿度变化引起的应变应力特性进行描述.基于模型对不同水灰质量比及养护条件下的自干燥、自收缩、单轴扩散干燥试验进行模拟验证,并进行干湿循环试验的数值模拟.结果表明,所提模型具有较好的适应性,可以准确模拟试验中湿度和应变的演变过程,在干湿循环试验中由湿度引起的应变应力特性符合一般规律.该模型可以为水工混凝土结构的安全评估和寿命预测提供支撑.

A fixed thermo-hygro-chemical-dry-wet strain(THCD)multi-field coupled model was established based on the basic theories,in order to accurately study the characteristics of strain and stress caused by humidity change for hydraulic concrete in service environment.Based on the existing model,optimized chemical affinity function and adsorption isotherm equation were introduced to realize accurate simulation of hydration process and multi-stage evolution of humidity.And the relationship between humidity and strain was established further,so that the model can describe the characteristics of strain and stress caused by humidity change.Based on this model,self-desiccation,autogenous shrinkage and uniaxial diffusion drying tests were simulated and verified under different water-cement ratios and curing conditions,and the numerical simulation of dry-wet cycle test was carried out.Results show that the model has good adaptability,which can accurately simulate the evolution process of humidity and strain in the tests.The characteristics of strain and stress caused by humidity in dry-wet cycle test conform to the general law.This model can provide support for safety evaluation and life prediction of hydraulic concrete structures.