単杭の杭周地盤ばねの評価法に関する検討

摘要

This paper describes the evaluation method of soil springs in the design of the pile foundation in which a pile is expressed with beam elements and the ground with soil springs of horizontal and vertical directions. The proposed model of soil springs is based on the concept of the subloading surface model that realizes a smooth transition from elastic state to plastic state of the soil. Simulation analyses of lateral and vertical loading tests in an actual ground were carried out by using the proposed model. The computed results show a fairly good agreement with the test results.%本論文では単杭を対象に，杭を曲げせん断軸力要素，杭周地盤を深さ方向に離散化した地盤ばねでモデル化した設計モデルにおいて，微小変形から極限状態まで連続した杭周地盤ばねの設定方法について検討を行い，下記の結果を得た。1）水平方向の分布ばねは，Vesicのばねの2倍を用いることで杭頭水平剛性を評価でき，杭頭曲げモーメントに関しては16%から24%程度大きく評価する。