自锁型围护桩在深水基础施工中的应用

研究目的:本文结合兰州地区黄河特大桥建设中遇到的深水基坑问题,在对既有类似工程各种措施的适用条件和优缺点进行分析的基础上,探讨采用何种措施既能对基坑开挖进行安全围护又能有效防水。研究结论:自锁型钻孔嵌套桩作为一种新型基坑围护结构,充分利用了实际地质条件,将钢筋混凝土桩作为竖向支撑梁,利用基岩对桩底端的水平约束和桩顶端锁口圈梁的水平约束使之形成一个稳定的自锁型支护体系,避免了基坑开挖过程中逐级施作支撑的问题,素混凝土桩和钢筋混凝土桩的嵌套体共同形成密闭止水帷幕彻底解决了已有钻(挖)孔桩达不到充分止水的问题。这样就将钻孔灌注桩既作为支护结构又作为止水帷幕来综合利用,克服了传统的深水基坑围护结构防水性能差、安全性低的缺点,同时有效降低了施工成本。

Application of Self- locking Fender Pile in Deep Water Foundation

Research purposes: For the problem of the deep water foundation encountered in construction of the Yellow River bridges in Lanzhou area,this paper discusses taking what kind of the measures that can safeguard the excavation and waterproof of the deep foundation,analyzes the applied conditions,advantages and disadvantages of of the various engineering measures taken for the similar projects in the past,and offers a though of taking the self-locking boring nest pile as the protection structure of the foundation. Research conclusions:As a new type of foundation protection structure,it makes the full use of the geological conditions to take the reinforced concrete pile as the vertical support beam,and uses the level bound of the foundation rock on the pile bottom end and the level bound on the periphery beam of the fore shaft on the pile top end to form a stable self-locking support system to avoid making the support system in every steps during the foundation excavation.The plain concrete pile and reinforced concrete pile are nested to form a water-stop curtain to fully stop the water that is not achieved by the boring piles.In this way,the boring cast pile is used as the support structure and at the same time as the water-stop curtain to overcome the problems of the poor waterproof property and low safety,and at the same time it effectively cuts the construction cost.