The Deformation Analysis Of Composite Foundation Of Tank Subjected To Earthquake

At present, with the rapid development of petroleum and chemical industry in China, the use of large storage tank is increasing, so the requirement of foundation treatment becomes stricter. Among the methods of soft storage tank foundation treatment, the composite foundation is commonly used. Based on the composite foundation of tank, FLAC3 D is used in this paper to numerically simulate the natural foundation, composite foundation with gravel column and CFG composite foundation subjected to earthquake, and analyze dynamic response and deformation characteristics of foundation under different seismic amplitudes, different additional loads and different pile parameters(pile diameter, pile length, pile stiffness). Finally, composite foundation with multiple reinforced of different materials is simulated, and the influence of different proportion of pile on dynamic characteristics of composite foundation is analyzed. Main conclusions in this paper are as follows:(1) Under the action of earthquake, the horizontal acceleration of the natural foundation amplifies from bottom to top, nonlinear performance of the dynamic deformation of soil is more obvious,and pore pressure accumulates gradually to the peak. Dynamic pore pressure basically remained stable, as the input earthquake acceleration is abate. And settlement drops quickly at the initial stage of the earthquake, later, with the decrease of the earthquake acceleration, settlement becomes stable and uneven settlement appears. After the earthquake, the initial settlement declines faster, and then with the time goes by, consolidation settlement is gradually slow.(2) Under the action of earthquake, soil settlement and the peak of horizontal acceleration between single type of pile composite foundation has an obvious decrease, CFG composite foundation is decreased more apparent than composite foundation with gravel columns in the settlement and acceleration. After the quake, consolidation settlement of single type of pile composite foundation is obviously decrease, and variation rate slows significantly, thus has an evident reinforcement effect.(3) The pile diameter, pile length, pile stiffness,additional load and seismic amplitude have a certain influence to seismic response of single type pile composite foundation,and the influence of additional load and seismic amplitude is more obvious.(4)Under earthquake, with the addition of CFG pile, composite foundation soil settlement decreases gradually. As the CFG pile increases, the whole strength of composite foundation has a larger enhance, and its deformation tends to sink as a whole. When the proportion of CFG pile and gravel column is 5 to 4, the reinforcement effect is relatively remarkable.