Analysis of dynamic stability of foundation pile stretching out of ground

Based on principle of Hamilton,the formulas to calculate exciting frequency of piles under axial dynamic load are derived.The problems of dynamic stability of foundation pile stretching out of ground are studied. The effects of different restriction of pile end,pile length ratio,pile diameter ,horizontal resistance of soil and exciting frequency on dynamic stability of foundation pile are discussed.The distinction of dynamic nonstability area of piles under different restriction condition at pile end are studied.