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为研究下沉式地下结构顶板在温度变化作用下应力分布规律及保护措施,对某下沉广场顶板在季节温差和不同季节日温差作用下、结构设置和不设置变形缝情况下的应力和变形情况进行了数值模拟。结果表明:温差作用下,无论是否设置变形缝,结构均会在板梁相交处产生超过混凝土极限抗拉强度的拉应力,设置变形缝对温度应力影响不大;顶板受力和位移中,温度作用所占比重在日温差最不利工况中分别为33%和78.9%,季节温差最不利工况中分别为24.2%和98.7%,应采取加强配筋、保温防裂等措施。通过改变结构顶板上表面的温度,得到了结构上表面所配钢筋数目线性递减的规律,建议下沉结构顶板应以上表面温度为5℃作为控制基准设置保温层。
In order to study the stress distribution and protective measures of the roof of subsidence underground structure under the influence of temperature changes, the stress and deformation of the roof of a subsidence square under the conditions of seasonal temperature difference and daily temperature difference in different seasons, The situation was numerically simulated. The results show that under the action of temperature difference, the structure will produce tensile stress exceeding the ultimate tensile strength of concrete at the intersection of the slab and beam, no matter whether the deformation joint is set or not. The deformation seam has little effect on the temperature stress. In the roof stress and displacement, The proportions of the effects are 33% and 78.9% respectively in the most unfavorable conditions of daily temperature difference, and 24.2% and 98.7% respectively in the most unfavorable conditions of seasonal temperature difference. Measures such as strengthening reinforcement and heat preservation and cracking prevention should be taken. By changing the temperature of the upper surface of the structure roof, the law of the number of steel bars on the upper surface of the structure is linearly decreasing. It is suggested that the roof of the sinking structure should be set with the upper surface temperature of 5 ℃ as the control reference.