Experiment and Calculation Method Study on a New Composite Foundation for Transmission Lines Engineering

The geological condition of 500 kV transmission lines in hilly and mountainous areas is generally covered by clay layer on the surface with depth of 1.5-2.5m.In this area,the use of digging foundations or rock anchor foundations alone will not meet economical requirement and environmental protection.Combined the advantages of digging foundations and rock anchor foundations,a new composite foundation is designed in this paper,which is digging-anchor composite foundation.The bearing capacity and deformation characteristics of digging-anchor composite foundation are investigated through experiment.The results show that digging-anchor composite foundation can satisfy the requirements of bearing capacity.According to the test results and technical specification for designing foundation of overhead transmission lines,the design calculation formulae of digging-anchor composite foundation is proposed.