Coral soil is mainly composed of calcareous sand and reef limestone. A series of in-situ static loading tests was conducted in the prestressed high strength concrete(PHC) piles located at the coral soil

which were used to clarify the interaction between PHC piles and coral soil while loading. Fiber bragg grating(FBG) sensing technology was applied to collect strain values along pile shaft during tests

and then pile axial forces were calculated. Base on the values of axial forces

the piles bearing capacities have been analyzed. Experimental resutls show that: (1) the responses of pile-soil are in the linear elastic stage during these tests; (2) the bearing performance of pile is significantly related with its penetration depth in the soil. When the penetration depth exceeds 15 times of the pile diameter

the resistance at the tip of the pile reaches its peak; (3) the installation style of the pile hardly affects its bearing capacity in coral soil

but it significantly affects the penetration energy; (4) the penetration depth and energy affects the degree of fragmentation of the coral soil

which constrains the bearing capacity of pile. Based on in-situ testing

it can be seen that in the coral soil

when the penetration depth is less than 15 times of the pile diameter

the penetration depth is positively correlated with the resistance at the tip of the pile

and is inversely related to the friction resistance at the side of pile .