旋喷锚桩在软土地区超大深基坑中的应用

天津嘉里中心基坑开挖深度17m,周边环境复杂(津滨轻轨地铁距离基坑30m)。为满足项目开发进度需要,采用旋喷锚桩施工技术替代原设计中心岛法边撑。利用旋喷和搅拌工艺在软土地区中形成大直径锚固桩体,达到增加锚固体抗拔力的效果,并可以有效地改良土体,提高土体自身抗剪强度。通过数值模拟手段,制定了施工工艺参数和完善施工流程。施工监测结果表明,旋喷锚桩技术的应用保证了地铁隧道的变形安全,成功解决了锚固技术在软土地区难以适用的难题。

Application of Rotary Churning Pile Construction Technology for Super Large Deep Foundation Excavation in Soft Soil Area

In foundation excavation of Tianjin Kerry Center,the depth is 17m.Its surrounding environment is complex with a distance of 30m to Jinbin Light Rail.To meet the needs of project development,central-island method is replaced by rotary churning pile construction technology.The large-diameter anchor piles with process of rotating and mixing in the soft soil,effectively increase the anti-pull strength of anchorage body,and improve the shear strength of soil.By means of numerical simulation,the construction parameters are formulated and the construction process is improved.Construction monitoring results show that the application of rotary churning pile ensures the safety of subway tunnel,successfully solves the problem that anchoring technology is difficult to apply in the soft soil,and provides a reference for design and construction of super large deep foundation excavation in soft soil area.