In-situ vertical load test of piled raft foundation and corresponding simulation using 3D finite element analysis

Piled raft foundation is a common foundation structure that reduces settlement of structures by adding piles to raft
foundation. It is well known that the bearing capacity and settlement behaviors of a piled raft foundation are
complicated. Numerous experiments and analyses have been conducted to clarify the load sharing between piles and
rafts and the settlement behavior of piled raft foundations. However, there are not so many cases in which the actual
behaviors, such as the load sharing between piles and raft and the settlement, have been confirmed by in-situ loading
experiments. In this study, an in-situ vertical load test on a piled raft foundation model was conducted on a test site. In
the test site, volcanic cohesive soil was found below the top fill layer of 1 m thick. The volcanic soil layer was underlain
by tuffaceous clay, sandy silt and sand layers. The piled raft foundation model was composed of a square concrete raft
of 1.5m × 1.5 m × 0.5 m supported by four steel pipe piles with an outer diameter of 101.6 mm and a length of 3.5 m.
3-dimensional finite element simulation was conducted to get deeper insight into the bearing mechanism of the piled
raft foundation model.