| Budget Amount *help |
¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1987: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1986: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Research Abstract |
The results and informations obtained from theoretical and experimental studies on the lateral behavior of pile group foundations up to failure under combined load can be summarized as follows.
1. In order to apply simultaneously both axial and lateral forces at the cap of pile group foundation, the apparatus having the lateral moveng container on two rails was developed. the accuracies of conditions during all tests carried out were examined.
2. Group efficiency due to the interaction of piles gradually decreases as the pile spacing, R, increases. For R=2D(D:pile diameter), however, it is observed that the behavior deffers from others because of arch-action in sand. Furthermore, it is indicated that at the ultimate state of pile group foundations the deflection decreases and the lateral resistance increases as R increases.
3. In general, it is found that the group reduction factor decreases with increasing numbers of piles in a group, and increase in number leads to increase in ductility of pile group foundations.
4. For the pile groups subjected to vertical load, the lateral load-deflection curves have a peak, and the ultimate lateral resistance is reduced because of the additional moment caused by deflection, as compared the results without vertical force.
5. The analytical method, in which the method of incremental displacement is used to predict the nonlinear behavior up to failure due to yielding of soil and pile, is predicted. Comparisons between the observed and predicted load-deflection behavior are made. It is found that the agreement between predicted and observed curves is reasonable for single piles and pile groups at large spacings, but the theory overpredicts movements and underpredicts ultimate lateral resistances for pile groups at close spacings.
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