薄壁水池混凝土结构变形缝间距设置分析研究

Analysis and Study on Setting of Deformation Joint Spacing for Concrete Structure of Thin-wall Water Tank

长大薄壁结构容易在早龄期发生非受荷开裂现象,不仅影响结构的安全使用,也大大影响结构的耐久性,因此各类规范对此类混凝土结构的一次浇筑长度提出了限制要求。但是,对长大混凝土结构而言,较多的变形缝将延长结构工期,增大基坑开挖风险。为得到合适的变形缝设置间距,以上海竹园三厂沉淀池为例,通过数值计算方法,计算分析了一次浇筑30 m、50 m、70 m、90 m共4种工况下的混凝土早龄期开裂风险,并以此提出了此类薄壁结构减少变形缝、增加一次浇筑长度的依据。

Long and large thin-wall structures are prone to unloaded cracking in the early age,which not only affects the safe use of the structure,but also greatly affects the durability of the structure.Therefore,all kinds of specifications put forward the limitations of pouring length once for this kind of concrete structure.However,for the long and large concrete structures,more deformation joints will prolong the construction period and increase the excavation risk of foundation pits.Taking the sedimentation tank of Shanghai Zhuyuan Plant No.3 as an example,the numerical calculation method is used to calculate and analyze the risk of cracking in early age of concrete under four working conditions of pouring once of 30 m,50 m,70 m,and 90m.For this reason,the basis for decreasing the deformation joints and increasing the pouring length once of this kind of thin-wall structure is proposed.