成本管控下高层建筑CFG桩复合地基优化设计

OPTIMIZATION DESIGN OF CFG PILE COMPOSITE FOUNDATION FOR TALL BUILDINGS UNDER COST CONTROL

为降低工程成本,对漯河市某在建高层建筑地基进行方案优化。以项目中的15号楼为例,考虑桩长和桩间距两个因素,设计3种CFG桩复合地基比选方案,满足承载力要求的前提下以经济性作为评价指标,计算3种比选方案的工程造价并与原设计方案进行对比分析,研究结果表明:当桩长为16 m、桩直径为0.4 m、桩间距为1.35 m时为最优方案,仅单栋建筑比原设计方案节约造价20.142万元。为进行不同地基基础方案对比,设计桩间距亦为1.35 m的预应力高强混凝土管桩地基方案,并根据桩端持力层深度确定桩长为22 m。管桩内径为0.21 m,外径为0.4 m,桩周长为1.26 m,承载力满足要求。计算该方案工程造价,与CFG桩复合地基方案中的最优方案进行经济性对比,结果表明:仅单栋建筑采用CFG桩复合地基优化方案较管桩方案可节省工程造价57.806万元,对于需要进行地基处理的11栋楼仅复合地基就可节省约635.866万元,因此,最终确定该工程项目采用CFG桩复合地基优化方案。

In order to reduce engineering cost,optimized design schemes are discussed for the foundation of tall buildings in Luohe City.Three kinds of CFG pile composite foundations were designed for building 15 as an example,which have different pile length and space.Then the bearing capacity of each scheme was calculated and proved to be reasonable.After that,the project cost was figured out and analyzed in order to choose the most economical option.It was shown that scheme 2 was the optimal one which was with pile length of 16 m,pile diameter of 0.4 m,and pile space of 1.35 m.It saved 201420 yuan only for a single building than the original design.In order to compare different foundation schemes,the prestressed high strength concrete pipe pile foundation scheme was also designed,which was with the same pile space of 1.35 m.The pile length was 22 m according to the depth of the pile tip bearing layer.What else,the pile inner diameter was 0.21 m,the outer diameter was 0.4 m,and the pile circumference was 1.26 m.The bearing capacity of pipe pile foundation met code requirements.Afterwards,the project cost of this scheme was also figured out to be compared.It was shown that the optimization scheme of CFG pile composite foundation for a single building can save the project cost of 578060 yuan,as for the entire project,it will save about 6358660 yuan.As a result,CFG pile composite foundation of scheme 2 was the optimal scheme to use in this project.