THE EFFECTS OF PARTIAL EMBEDMENT OF A HELICAL SCREW PILE INTO A BEARING LAYER ON ITS PENETRABILITY AND LOAD-SETTLEMENT BEHAVIOR

Abstract

The authors examine how partial embedment of a helical screw pile into a bearing layer affects on its penetrability and load-settlement behavior. Both large-scale model tests and field tests had been conducted taking embedment length into account. For model tests, two layered sand deposits with different relative densities were prepared in a calibration chamber. The test results show the following regardless of the test scale; a torque profile and a penetration rate start change just before reaching a pile toe into a bearing layer. Embedment length equal to a screw diameter, which is commonly required in practice, yields effective mobilize of the end-bearing resistance beneath the helical screw, while less resistance tends to mobilize beneath the pile shaft as embedment length increases. As far as the bearing capacity of a pile is concerned, however, no significant influence can be observed in terms of embedment length into a bearing layer.