屈建民
    （北京市卫建设计所  100054）

[提要]  结合一个原设计是锤击预制桩基础后改为大直径人工挖孔扩底桩基础的工程，总结变更设计的成功之处，并对如何合理应用大直径人工挖孔扩底桩基础提高经济效益进行了探讨。
[关键词]  挖孔扩底桩 经济效益

Compared to primary design of precast pile, a new design is applied in the large diameter pile with bulb shaped size, wluch reduced the cost of the foundation by one third and improving the economic and social profits greatly. The suitable condition and the practical application of large diameter pile with bulb shaped bases are profoundly discussed.
Keywords:  pile with bulb shaped bases;profit