BIOT'S CONSOLIDATION THEORY BASED THREE-DIMENSIONAL NUMERICAL ANALYSIS FOR EARTHQUAKE RESPONSE OF STONE COLUMNS COMPOSITE FOUNDATION

Saturated sand was looked as a soil-water two-phase medium. A fully coupled three-dimension effective-stress dynamic analysis software was developed on the basis of Biot's consolidation theory. Stone columns composite foundation was analyzed using software. The research shows that the reduced vibration effectiveness of stone columns is very remarkable, and the surface maximum horizontal vibration acceleration of stone columns composite foundation is bigger than that of natural foundation. Moreover, the stone columns can restrain settlement of foundation. The drainage effectiveness of stone columns is very remarkable. With decreasing of input earthquake acceleration, the dissipation of pore water pressure starts after the peak value has reached. The effective influence domain of stone columns is a circling platform with narrow upside and wide underside. The densification effectiveness of stone columns is remarkable. The excess pore water pressure ratio considering coupling effectiveness is smaller than that only considering some effectiveness or other. So the coupling effectiveness of stone columns should be considered when judging of anti-liquefaction capability of stone columns composite foundation.