Strength evolution model of hydraulic concrete subjected to salt freezing
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摘要: 寒区盐湖、盐渍土地区水工混凝土结构强度劣化问题突出。基于各向同性连续损伤力学理论,建立了混凝土相对动弹性模量与相对抗压强度的定量关系,提出了硫酸盐侵蚀和冻融协同作用下水工混凝土强度演化模型,并进行模型验证,最后将模型应用于引大入秦庄浪河渡槽结构性能评估。结果表明:该模型能较好地反映受盐冻侵蚀作用下混凝土强度的变化规律;渡槽数值计算结果与运行状况相符,随盐冻侵蚀劣化时间增长,槽身最大压应力和最大位移增加,最大拉应力减小;盐冻协同作用会加快渡槽劣化速率,渡槽运行59.1 a后会发生破坏。研究结果可为寒旱地区受盐冻侵蚀水工混凝土性能评估和运行维护提供理论依据。Abstract: The problem of strength deterioration of hydraulic concrete structures in salt lakes and saline soil areas in cold regions is outstanding. Based on the theory of isotropic continuous damage mechanics, the quantitative relationship between relative dynamic elastic modulus and relative compressive strength of concrete was presented. Next, a concrete strength evolution model under the synergistic action of sulfate erosion and freeze-thaw was proposed, and the model was verified. Finally, the model was applied to the verification and performance evaluation of Yindaruqin aqueduct over the Zhuanglang River. The research results show that the model can well simulate the strength evolution law of concrete subjected to salt frost erosion. Through numerical simulation analysis, it is found that the numerical results of the aqueduct are consistent with the operating conditions. With the deterioration time increasing, the maximum compressive stress and displacement of the aqueduct body increase, while the maximum tensile stress decreases. Salt freezing will accelerate the deterioration rate of the aqueduct, and the aqueduct would be damaged after 59.1 years of operation. The research results can provide a theoretical basis for performance evaluation and operation maintenance of hydraulic concrete eroded by salt freezing in cold and arid areas.
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Key words:
- freeze-thaw /
- sulphate attack /
- concrete /
- strength evolution model /
- numerical simulation
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表 1 混凝土材料参数
Table 1. Concrete material parameters
名称 弹性模量/GPa 泊松比 密度/(kg·m−3) C30混凝土 30.0 0.2 2 360 C40混凝土 32.5 0.2 2 400 C50混凝土 34.5 0.2 2 440 表 2 不同运行劣化时间下槽身应力和位移极值分布
Table 2. Distributions of stress and displacement extremes at different degradation times
劣化时间/a 最大压应力/MPa 最大压应力
发生部位最大拉应力/MPa 最大拉应力
发生部位最大位移/mm 最大位移发生部位 0 9.383 渡槽槽身板、槽底板和上横系杆 1.949 槽身板与槽底板交接处 15.18 槽底板处 26 9.844 渡槽槽身板、槽底板和上横系杆 1.943 槽身板与槽底板交接处 17.15 槽底板处 59.1 11.440 渡槽槽身板、槽底板和上横系杆 1.922 槽身板与槽底板交接处 24.73 槽底板处 -
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