Research On The Mechanism And Characteristics Behavior Of Y-shaped Sinking Pipe Pile Under Vertical Loads

In order to improve the current situation that the round cross-section of the sinking pipe pile limits the full exertion of the potential of pile and soil, Lu Jianhua propsed the Y-shaped sinking pipe pile by combining the technique of the large Y-shaped pile abroad and that of the sinking pipe pile at home, which changes the round pipe model into the Y-shaped pipe model, so that it can benefit from a higher bearing capacity of the abnormal-cross-section and a higher speed construction of the sinking pipe pile. As a new technique to improve soft ground, the research on the Y-shaped pile is just at the starting phase, its vertical bearing capacity should be analyzed.The outlines of this thesis where as follows: first of all, the field test on the vertical bearing capacity of the Y-shaped pile was carried out, then its bearing capacity was analyzed on the basis of the test results; finally, FEM was used to simulate the field test and the characteristics was further expounded on. The principal contents are as follows:(1) The state-of-the-art techniques and theories on the vertical bearing capacity analysis were reviewed; the invention and the design of Y-shaped pile tip were pile tine are introduced; its constructing way and craftwork process were also expounded on; some suggestions were given on the quality control and inspection.(2) On basis of field measurements and instrumentations, the bearing behavior of Y-shape pile was analysed, including horizontal displacement of deep soil, ground surface uplift, lateral pressure induced by squeezing soil, pore pressure caused by pile driving, settlement of embarkment pore pressure development and axial force.(3) Field tests were simulatated by faking use of Abaqus, the results were compared with field measurements, which help understanding the working behavior of Y-shape pile.