To study the load settlement characteristics and load-transfer mechanism of cast-in-situ X-shaped concrete piles

full-scale model pile load test of X-shaped pile is carried out by using the large-scale test trench of Hohai University. The interaction behavior of the vertical loaded X-shaped piles is obtained by means of the reinforcement stress gauges set in the pile and earth-pressure boxes embedded in the pile bottom. The experiment results show that: X-shaped pile load settlement curve is an adjustment curve; pile side friction and tip resistance show incremental development with the increasing pile settlements; but with the increase of pile top load

the ratio of pile side resistance sharing pile head load is regressive

its sharing ratio decreases from the initial load of about 90% to 70% of the limit state

while the ratio of tip resistance sharing the load is incremental

the pile top load-sharing ratio of about 10% from the initial state up to 30% of the limit. The research results are useful for the design and analysis of X-shaped piles under vertical load.