沉井顶钢板桩防水围堰,在我们所了解到的几座大桥施工中曾出现过几次较大的事故。例如某桥有个φ18米圆形沉井,由于在下沉过程中引起大翻砂,将整个钢板桩围堰胀得象个痰盂,形成一个大鼓肚,致使沉井无法继续下沉到设计标高,原为沉井下到岩面加钻孔的基础,不得不改 Caisson roof piles waterproof cofferdam, we have learned several bridge construction has occurred several major accidents. For example, a bridge has a φ18 m round caisson, due to the process of sinking caused by the large sand, the entire steel sheet pile cofferdam bulging like a spittoon, forming a big bulging, resulting in caisson can not continue to sink to the design elevation, the original To caisson down to the rock surface plus drilling, had to change