荆江大堤防洪闸闸室底板预留宽缝研究

Research on preserved wide construction joints at bottom floor of flood control sluice in Jingjiang Dike

软土地基上的防洪闸闸室常采用坞式结构,其底板一般采用传统的整体式浇筑方法施工,这种施工方法虽使结构的整体性好、地基反力分布均匀,但底板受力状态较差,顶部拉应力大,容易出现不同程度的裂缝,进而影响建筑物的正常使用。荆江大堤防洪闸共两孔,采用整体"W"型结构,单孔净宽32.0 m,闸室总宽度84.0 m。为防止底板出现裂缝,设计提出施工期间在底板上预留宽缝,并采用"墩底分浇、预留宽缝、后期封合"的施工方法。计算分析表明,采用这种施工方法后,底板的受力状态较整浇时得到了明显改善。工程完工后近2 a的监测数据表明,防洪闸运行情况良好,底板受力状态较好,底板表面基本无裂缝。

The dock structure was often adopted for the chamber structure of flood control sluice on the soft foundation, and the conventional integral pouring method was used for bottom floor construction. Although the entirety of this structure is good, and the foundation reaction force distributes uniformly, the stress state of the floor is poor with large tension stress at top, so cracks may occur at different degree, which can affect the normal operation of the structure. Two outlets were adopted by flood control sluice in Jingjiang Dike in W shape with each width of 32. 0 m, and the total chamber width of 84. 0 m. In order to prevent the cracks at bottom floor, the wide construction joints were preserved in pouring construction, and the method of＂separately pouring for pier bottom, setting up wide construction joints and closing in later period＂ was adopted. The calculation results show that the stress state of bottom floor during pouring was improved. The monitoring data for 2 years show that the flood control sluice has been running in good condition, the stress state of bottom floor is better, and no cracks occurred at the surface of the bottom floor.