The safety and stability of large boom internal climbing tower crane are very important in the construction of super high?rise buildings, and it is urgent to solve the problem that how the tower crane’ s supporting system affects the wall. This paper takes a project as the background, the field experiments were designed to collect data by field test. According to the experiments, some mechanical properties of attached wall have been researched, such as the effective width of attachment wall and lifting coefficients.

Processing the barrier met in the foundation pit construction when rebuild in the existed building site is one of the construction difficulty. According to the Nankai center project in financial street in Tianjin, this paper introduces several processing methods of underground obstacles in the construction of foundation pit, and makes a brief analysis. Practice shows that these methods can ensure the construction of engineering pile, support structure and the earth excavation successfully, and can protect the safety of surrounding environment, provide the reference for the future similar engineering construction.

根据津门工程地下室结构尺寸与地质水文条件,采用三轴止水帷幕+护坡桩+3道水平撑的支护形式,全顺做方案。通过调整基坑内支撑设计,在其满足基坑支护要求的基础上,使其避让主楼结构投影范围内的地下室竖向结构;通过调整地下室结构施工工序,将整体地下室部分分成主楼结构投影范围内和非主楼投影范围内两部分,主楼投影范围内的地下室结构在内支撑不拆除的条件下组织施工;对内支撑横向穿越先行施工部分的施工节点进行深化设计,确保不影响结构施工同时不影响基坑支护安全;对先行施工部分与后续施工位置节点进行深化设计,确保施工质量。

通过采取起爆网络设计、严格控制爆破参数等措施,避免了爆破飞石、爆破震动、爆渣块过大,对地下室底板破坏等难题。采用此爆破方法,前期准备工作可交叉施工,不占工期,爆破的瞬间可完成大量(500~1000 m~3)钢筋混凝土的破碎工作;混凝土破碎效果好,爆破后的钢筋与混凝土完全剥离,便于人工铲装及运输,回收钢筋长且直,回收率高。

The pit project in Tianjin Jinmen is large area and deeper,the site is limited,geological environment condition is complex,the pit excavation is affected by the confined groundwater,the quantity of support structure and earthwork is large.Detailed key point,steps and results of construction scheme of support pile,soldier pile,inner support,reduce level of water,earthwork,blast to demolish the inner support and so on were introduced detailed in the paper;The informationization supervision and measure was fulfilled for the deep pit during construction,and thus provided guarantee for the project fulfill successful.The fact prove that,the effect of construction measures was good,the technique difficult problems of super large and deep pit under the complex environment conditions during construction was solved effectively.

根据场地工程地质与水文地质条件,对天津某基坑支护采用放坡与钢板桩支护方案,并指出该支护的优点及施工方法,为此类基坑支护提供经验.