EXPERIMENTAL STUDY ON THE VELOCITY DEPENDENCY OF AXIAL SOIL SPRING FOR BURIED PIPE BY SHAKING TABLE (PART 2)

Abstract

 Axial soil spring between the pipe and ground is treated as the Coulomb's friction law in the seismic response analysis of buried pipeline, for water and gas supply, etc. In order to investigate an axial soil spring considering the velocity dependency of soil friction, the pipe pulling-out test using the shaking table was carried out in addition to our previous tests. Not only the pipe moving velocity but also soil and install depth were dealt as the parameter. In the slow-moving cases, the friction coefficient was 0.4 to 0.6 regardless of the soil and pipe material. The positive velocity-dependency appeared in the cases of cohesive soil with low water content, whose maximum shear stress increased 1.2 to 1.4 times comparing to that of the slow-moving cases. The cases of sandy soil with low water content did not show the positive velocity-dependency.