淮阴三站裂缝形成原因分析

Analysis of causes of cracks in Huaiyin Third Station

淮阴三站为南水北调东线工程第三梯泵站重要组成部分,工程运行后,在空箱隔墩中部发现裂缝,通过探索裂缝形成原因,分析比较不同裂缝处理方法成效。以该泵站高程9.7m以上部位混凝土裂缝为例,通过稳定计算和三维有限元数值模拟,分析在设计抽水期Ⅰ、设计抽水期Ⅱ及地震期3种不同工况下,温度变化时泵站裂缝处典型点应力值变化情况。结果表明:温度能够引起裂缝典型点处最大主应力值的变化,且温降时泵站裂缝处典型点应力变化值较大,即温降时混凝土拉应力增大产生裂缝的可能性较大。现场裂缝主要采取以下2种处理方法,缝宽大于0.2mm的采用灌浆法,缝宽小于0.2mm的采用有机硅封闭法。裂缝经处理后,均取得较好效果。

The Huaiyin Three Station is an important component of the third cascade of the Eastern Route of the South-to-North Water Transfers Project.After the operation of the project,cracks were found in the middle of the empty box pier.This article explores the causes of crack formation,analyzes and compares the effectiveness of different crack treatment methods,and provides reference significance for temperature crack treatment in other large pumping stations.This article takes the concrete cracks at an elevationof9.7 m or above in the pumping station as an example.Through stability calculation and three-dimensional finite element numerical simulation,it analyzes the variation of typical point stress values at the crack location of the pumping station under three different working conditions:design pumping period I,design pumping period II,and the most seismic pe riod,under temperature changes.The results indicate that temperature can cause a change in the maximum principal stress value at the typical crack point,and the stress change at the typical crack point of the pump station is relatively large during temperature drop.That is,there is a greater possibility of concrete tensile stress increasing and cracking during temperature drop.On site cracks are mainly treated using the fol lowing two methods:grouting method is used for cracks with a width greater than 0.2 mm,and organic silicon sealing method is used for cracks with a width less than 0.2 mm.After treatment,the cracks have achieved good results.