MODEL TEST ON SAND FLOWING AROUND PASSIVE PILE UNDER RECTANGULAR DISPLACEMENT MODE

Although the phenomenon of sand flowing around passive pile was observed,there is still a lack of systematical studies on the features of sand flowing as well as its related factors. Using the model experimental system designed and manufactured by Fuzhou University,the phenomenon of sand flowing around a circular passive pile was well tested and analyzed. The influence of pile diameter,loading velocity and sand density on the sand characteristic displacement and the pile drag force were studied. According to the test results,the sand flowing process around the passive pile could be divided into three stages: sand uplift on the head side,sand flowing around the pile and sand collapse on the back side. The increasing of pile diameter and sand density could hamper the sand flowing phenomenon around the pile,while the increasing of sand velocity could facilitate the sand flowing phenomenon. Furthermore,the position of sliding surface can be determined from the curve inflexion of drag force,the drag force above the sliding surface increased linearly with depth,and was always less than its counterpart calculated from the Shen-Zhujiang's formula.