In-situ test is the most objective and reliable method to obtain design parameters of pile foundations and to understand the pile mechanism. Based on the experimental equipment

such as fatigue machine

hoisting jack and so on

we researched a combination equipment of static and dynamic load on pile top

a key problem in the static-dynamic load test of pile has been solved. Static and dynamic load test in the filed of precast static pressure piles have been performed by use of combination equipment of static and dynamic load. Distributive regularities of inner force of pile under static and dynamic load

the change of pile’s side resistance

and settlement of piles are analyzed by static and dynamic load test. Test results show that the distributive regularities of side resistance of piles are substantial agreement in the process of static and dynamic load. Lateral friction in soft soil of pile stem upside decreases

and lateral friction in bottom soil layer increases; after three hundred thousand times has been vibrated

the side resistance of piles is without changing.