抄録
We proposed a simplified evaluation method for normalized force which means the ratio of each pile in the pile group to single pile on the ultimate ground reaction force. We use beam-spring model for the purpose of back calculation of the ultimate ground reaction force at each pile based on three-dimensional elasto-plastic analysis.
As a result, we found that the following trends from i) to iv).
i) The distribution of normalized force for sandy soil and clay soil are different. For sandy soil, the normalized force in the front row pile to the loading direction is largest and decrease sharply in the second row pile. From the third row pile to the back row pile, the normalized force shows the linearly decreasing characteristic. For clay soil, the normalized force decrease once toward the center row pile from the front row pile, it shows a tendency to be constant substantially toward the back row.
ii) Both sandy soil and clay soil, if pile's interval is wide enough, the ultimate ground reaction force is as same as that of single pile. On the other hand, if pile's interval is narrow, the ultimate ground reaction force is less than that of single pile and it means that the normalized force is less than 1.0.
iii) We proposed a simplified evaluation method for normalized force considering above trends of i) and ii). For sandy soil, the normalized forces in the front row pile, the second row pile and the back row pile are formulated. The normalized forces between the second row pile and the back row pile are assumed to be determined by linear interpolation.
iv) For clay soil, the normalized forces in the front row pile and the center row pile are formulated. The normalized forces are assumed to be determined by linear interpolation between the front row pile and the center row pile, and to be constant from the center row pile to the back row pile.
