Mechanical Behavior on Pile with Multi-Stepped Two Diameters under Combined Load

The model tests under lateral and combined load were conducted to verify the mechanical behavior on the rigid pile with multi-stepped two diameters. From the results of lateral load tests, the bearing capacity increases with the frontal projected area. For each pile, the lateral bearing capacity on the lateral load tests is smaller than the one on the combined load tests. Under combined load tests, the lateral soil pressure in MS-pile increases around the concave part to be push by vertical load. DEM analysis was also performed to evaluate the mechanical behavior under combined load. As the result of the DEM, the vertical loading before the lateral loading has the effect on the increase of the contact force between particles.

Based on above test results, the ultimate lateral bearing capacity was calculated. Under combined loading tests, the calculation method involves three assumptions. The predicted values using the method are in close agreement with the measured values at about 4% of lateral displacement ratio.