Estimation of External Force Acting on Steel Pile of Steel Pile Reinforced Breakwater

Abstract

The coastal areas of the Pacific Ocean suffered extensive damage by the tsunami of the 2011 off the Pacific Coast of Tohoku Earthquake. Then, there are needs to develop reinforcement methods of existing caisson type breakwaters against tsunami force. Installing a row of piles behind the caisson with backfilling the space between the caisson and piles with rubbles is proposed as one of the reinforcing methods against tsunami. In order to establish the design method of this reinforcing method, the design of the steel pile is the most important. For designing steel piles, it is necessary to estimate the load acting on them from the caisson side. Here, a series of model loading experiments were conducted. The experimental results suggested that the external force acts on the pile only in the ground at the initial stage of loading and it was found that the external forces acting on the piles dominate in the vicinity of the backfilling part by gradually compressing the backfilling part by displacement of the caisson.