基坑工程中锚索微型桩支护结构设计方法探讨

Discussion on Design Method of Supporting Structure of Anchor Cable Combined with Micro-Pile Used in Foundation Pit

微型桩作为预支护措施多与其他支护结构联合,以抗弯剪作用为主进行设计时,难以发挥其抗拉强度高的优势。本文针对锚索微型桩组合结构,根据混凝土结构设计相关理论,结合有关试验成果,通过受力特性与破坏模式分析,提出了一种新的设计计算方法,即认为混凝土不起承载作用,微型桩主要依靠钢筋承载,从而充分发挥微型桩的抗拉性能,因此称之为＂抗拉强度法＂。该方法在基坑支护实践中得到成功应用,效果良好。相对传统设计方法,可节约工程投资15%-20%。

Micro-pile as a pre-support measure has been widely used in foundation pit engineering,and always used with other reinforcement structures,mainly depended on bending and shearing action,not given full play to its advantage of the high tensile strength. Aiming at the composite structure of anchor and micro-pile,according to the relative design theory of concrete structures and combined with relevant experimental results,a new design method puts forward by analyzing the mechanical characteristics and failure modes,that is not concrete playing the role of supporting the load. Micro-pile works mainly by steel bar to maximize its tensile property, so called＂tensile strength method＂. The method has been successfully applied in the practice of foundation pit support with good effect,compared with the traditional design method can save engineering investment by 15% ~ 20%.