MODEL TESTS ON INSTALLATION AND SKIN BEARING CAPACITY OF SCREWED STEEL PILE WITH SPIRAL WINGS

Abstract

In order to evaluate the bearing capacity of closed end screwed pile with spiral wings, installation and loading tests were executed in uniformly graded sand in a calibration chamber. The experimental factors include the spiral wing diameter D_w (D_w/D_p=1.4-1.7, D_p :pile diameter) and the spiral pitch P (P/D_w=0.8-1.2). The test results and discussions have shown that : (1) The bearing capacity of the pile can be determined by the shear strength of cylindrical surface whose diameter is D_w, (2) There is a fairly-well defined correlation between skin bearing capacity and installation torque, and (3) The skin bearing capacity can be estimated using the torque acting on the pile shaft.