预应力锚索支撑体系在地铁明挖基坑中的应用

On the Application of the Reinforcing Anchor Rope Supporting System to the Open-Cut Foundation Pit of the Tube

沈阳地铁二号线某车站采用明挖法施工,设计选用了预应力锚索支撑体系。预应力锚索水平方向和竖向均有布置,其竖向锚索通过腰梁锚固在钻孔灌注桩上。一方面锚索的锚固力传递到防护桩上使土体密实;另一方面锚索施加的预应力作用改变了破裂面土体的应力状态,从而保证开挖基坑边坡土体的自稳能力。阐述了预应力锚索的施工原理与构造、施工工艺及技术要点。工程实践证明,深基坑施工采用预应力锚索支撑体系在围护结构的强度、整体稳定性和变形的影响方面优势明显。

A certain station of Line Two of the Shenyang Metro is built by means of open-cutting with the reinforcing anchorrope supporting system adopted. Reinforcing anchor ropes are provided both horizontally and vertically while the vertical anchorropes are anchored in the bored piles by way of mid-beams. On the hand, the anchoring force of the anchor rope is passed to the protectivepile to densify the earth body. On the other,the reinforcing action applied by the anchor rope changes the stress state of the brokenearth body so as to ensure the self stability of the earth body of the side slope of the excavated foundation pit. The constructionprinciple and composition,construction processes and technical characteristics of the reinforcing anchor rope are dealt with in the paper.Construction practice shows that the application of reinforcing anchor ropes to the construction of deep foundation pits as the supportingsystem has obvious advantages in maintaining the structural strength, the integral stability and in reducing the effect of deformation.