Large-Scale Model Testing and Analysis of Temperature-Induced Shrinkage Stress in Concrete Raft Foundations Constructed Using the Alternative-Bay Construction Method
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摘要: 为研究采用跳仓法施工的混凝土筏板基础温度收缩应力分布和发展规律,进行了大比例模型试验研究与分析。首先设计了采用跳仓法和设置后浇带施工的钢筋混凝土筏板对比试验模型,测量和分析了不同模型结构的温度及应力、应变变化发展过程,对比分析了不同施工方法的应力分布规律;其次进行了基于有限元数值模型的验证与参数分析。研究结果表明:跳仓法和设置后浇带两种施工方式下混凝土底板截面温度和应力发展变化趋势相似,应力大小和沿底板长度方向分布规律相近,但由于约束条件改变,跳仓法后浇底板的应力变化规律与其他底板不同,并且中部的应力大于后浇带法。采用跳仓法施工时需要通过控制中部截面的应力不超过抗拉强度,从而确保底板不发生开裂。Abstract: In order to investigate the distribution and development of temperature-induced shrinkage stress in concrete raft foundations constructed using the alternative-bay construction method, large-scale model experiments and analysis were conducted in this paper. Firstly, a reinforced concrete raft test model was designed employing both the alternative-bay construction method and post-pour strip construction method. The temperature and stress-strain variations of the structure were measured and analyzed, and the stress distribution patterns of different construction methods were compared and analyzed. Secondly, a numerical model based on the finite element software MIDAS FEA was established and verified against the experimental results. The research results indicated that under the two construction methods, the temperature and stress development trends of the concrete bottom slab section were similar, as were the magnitude and distribution of stress along the slab length. However, due to changes in constraint conditions, the stress variation pattern in the post-pour bottom slab of the alternative-bay construction method differed from that in the other slabs, with the stress in the middle section being greater than that in the post-pour strip method. Therefore, when using the alternative-bay construction method, it is necessary to control the stress in the middle section to ensure it does not exceed the tensile strength, thereby preventing cracking in the bottom slab.
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Key words:
- alternative-bay method /
- concrete raft foundation /
- temperature stress /
- shrinkage strain
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