锁扣钢管桩在基坑围护结构中的变形特性

Study on Deformation Characteristics of Latched Steel Pipe Pile in Foundation Pit Enclosure

锁扣钢管桩具有施工效率高、可回收重复利用等优点,逐渐被用于基坑围护结构中。为探明锁扣钢管桩在基坑支护中的受力和变形特点,开展锁扣钢管桩围护基坑开挖相似模型试验和数值模拟。通过对基坑地表沉降以及桩身位移进行监测,发现基坑地表沉降曲线随着开挖深度的变化,呈略微凸起的三角形曲线形式,随着基坑开挖深度的增加,沉降量逐渐增大,地表沉降曲线变为下凹的“勺形”变化。随着开挖深度进一步的增加,围护桩水平位移逐渐增大,上部变形在架设支撑后受到限制,后续开挖引起的桩体最大水平位移点随之下移,围护桩变形逐渐变为弓形。锁扣钢管桩在基坑围护中可以起到很好的限制土体水平位移的作用,为锁扣钢管桩在未来基坑支护中的应用起到了一定的参考作用。

With the advantages of high construction efficiency and reusability, lock-ended steel pipe piles are gradually used in foundation pit containment structures.In order to explore the force and deformation characteristics of the lock-jaw steel pipe pile in the foundation support, the similar model test and numerical simulation of the excavation of the foundation pit surrounded by lock-jaw steel pipe pile are conducted, and through the monitoring of the foundation pit surface settlement and pile displacement, the main conclusions are as follows: With the change of excavation depth, the surface settlement curve of foundation pit is a slightly convex triangular curve.With the increase of excavation depth, the settlement gradually increases, and the surface settlement curve becomes a concave “spoon” shape.With the further increase of excavation depth, the horizontal displacement of retaining piles gradually increases, and the upper deformation is restricted after erection of supports.The maximum horizontal displacement point of piles caused by subsequent excavation moves down, and the deformation of retaining piles gradually becomes bow-shaped.The locking steel pipe pile can play a good role in limiting the horizontal displacement of soil body in the foundation pit enclosure, which also plays a certain reference for the application of locking steel pipe pile in the future foundation pit support.