输电线路扩底人工挖孔基础设计方法分析

Study for belled manual excavation foundation in transmission line

人工挖孔基础由于充分利用原状土的性质,及其承载力高、经济性好、土石方工程量少等优点,因此在输电线路工程中得到广泛应用。与建筑工程上用的大直径扩底桩不同,输电线路人工挖孔基础需承受下压和抗拔两种荷载,为方便输电线路设计人员掌握其设计要点,对不同挖孔基础设计规程进行研究,系统地介绍了考虑扩大头的挖孔基础的设计原理、特点和计算方法。同时,对某750 k V输电线路工程的基础形式进行优化,结果表明,采用扩大头的人工挖孔基础能显著节省工程造价,应在电网建设中大力推广。

Due to the nature of full use of undisturbed soil,belled manual excavation foundation has characteristics of high bearing capacity,good economy and low earthwork,so itis widely applied in transmission lines.Compared with the large-diameter enlarged base pile used in common construction project,belled manual excavation foundation needs to withstand compressive load and uplift load in the transmission line.In order to help designers to master the design points on the design of the belled manual excavation foundation in transmission line,this paper summarized different technical regulations for excavation pile foundation,design principles,characteristics and calculation methods of the belled manual excavation foundation in detail and optimized foundation styles of a 750 kV transmission line engineering.The results show that belled manual excavation foundation can apparently reduce project cost,and it should be popularized and applied in the construction of power grid.