الفهرس | Only 14 pages are availabe for public view |
Abstract Soil liquefaction affects the maximum absolute bending moment acting on piles during and after earthquakes. In this research, a numerical model is prepared using the finite element program DIANA 9.3 (2008) in order to investigate the behavior of piles in liquefiable soil during earthquakes. The proposed model is able to represent the soil – structure interaction system under seismic excitation and submerged conditions. A wide range parametric study, considering submergence conditions, earthquake magnitude, earthquake duration, pile diameter and pile length has been carried out in order to investigate the behavior of such piles. Results show that earthquake magnitude, pile diameter, pile length and submerged conditions have major effects on the maximum absolute bending moments. Results of full submergence case reflect the great effect of soil liquefaction on increasing the bending moment acting on pile, as a result of increasing the laterally transmitted loads. Moreover, it is established that the loss of pile lateral supports due to soil liquefaction causes an increase in the unsupported length of pile, hence the possibility of lateral buckling. This behavior is obviously appears in cases of small pile diameter. Additional models with liquefiable soil layer thickness equal to 12 m have been carried out also, to investigate the location of point of maximum bending moment. The results show that the maximum bending moments, act on pile, occurred at the boundaries between liquefied and non-liquefied layers. Finally, recommendations for design of piles in liquefiable soil under seismic excitation conditions have been presented. |