Modeling of Soil Spring Perpendicular to Pipe Axis by Horizontal Loading Test of Buried Pipe

Abstract

In this study, horizontal loading tests were conducted on small-diameter buried pipes to evaluate soil spring characteristics for design and to propose an estimation formula for the subgrade reaction modulus (SRM). In the horizontal loading tests, steel pipes were buried in compacted wet sand in a soil tank. Steel rods were fixed to the ends of the pipes and loaded statically from the outside. The relationship between load and displacement was obtained. The relationship was approximated by the Weibull function, and the dependence of the SRM on the normalized displacement, on the loading width, and on the burial depth were evaluated respectively. In addition, the yielding displacement based on the maximum subgrade reaction and elasto-plastic model, and the relationship between the yielding SRM and the elastic SRM were clarified as the soil spring characteristics considering soil yielding. These results were used to construct a correction equation for the SRM obtained from the plate loading tests, and the validity of the correction equation was verified by multiple regression analysis.