软土地区超大地下空间围护方案选型和土方施工技术

Support Scheme Selection and Earthwork Construction Technology for Super Large Underground Space in Soft Soil Area

平潭高铁中心站综合交通枢纽及高铁中心站站前城市综合体项目,基坑面积大,开挖深度深,地质条件差,周边环境复杂,给基坑方案选型和土方开挖带来一系列技术难题。通过采用分区分级支护技术,根据不同区域施工条件,分2级卸荷土方,分级支护,并采用盆式土方开挖方法,成功解决了相关难题。施工结果表明,分级支护结合盆式开挖可以避免设置大面积水平支撑,有效地缩短了基坑及地下空间结构的施工工期,减少了工程造价,总结的经验可为软土地区超大深基坑设计和施工提供参考。

The comprehensive transportation hub of Pingtan high speed railway central station and the urban complex project in front of Pingtan high speed railway central station have large foundation pit area,deep excavation depth,poor geological conditions and complex surrounding environment,which bring a series of technical problems to the foundation pit scheme selection and earthwork excavation.By adopting the divided and graded support technology and according to the construction conditions in different areas,the two-level divided earthwork unloading,the graded support and the basin earthwork excavation method are adopted to successfully solve the relevant problems.The construction results show that the graded support combined with the basin type excavation can avoid the setting of large-area horizontal support,effectively shorten the construction period of foundation pit and underground space structure,and reduce the project cost.The summarized experience can provide reference for the design and construction of super deep foundation pit in soft soil area.