Behavior Of Piled Raft Foundation Research Articles

パイルド・ラフト基礎の簡易算定法の検討

A simple approach for calculating the behavior of piled raft foundations subjected to a vertical load in homogeneous soils is investigated. The vertical stiffness (Kana) and the pile head load ratio (Ψana) of piled raft foundations were clarified based on parametric studies by the hybrid method, and these values were compared with the results using the AIJ formula. As a result, we presented the new simple method for quickly and easily calculating the vertical stiffness (Kcal) and the pile head load ratio (Ψcal) of piled raft foundations which have various parameters.

水平力を受けるパイルド・ラフトの挙動に関する杭頭接合条件の影響(その2 実験結果および考察)

水平力を受けるパイルド・ラフトの挙動に関する杭頭接合条件の影響(その2 実験結果および考察)

水平力を受けるパイルド・ラフトの挙動に関する杭頭接合条件の影響(その1 原位置載荷実験の概要)

水平力を受けるパイルド・ラフトの挙動に関する杭頭接合条件の影響(その1 原位置載荷実験の概要)

地下水揚水に伴う地盤沈下時のパイルドラフト敷設効果

The behavior of piled raft foundations on natural deposited soils subjected to ground subsidence due to dewatering is analyzed in this paper. A three-dimensional finite element model considering the soil-water coupled problem has been developed. In this analysis the piled raft and the soil are modeled as an elastic material and a two-phase elasto-plastic material, respectively. It can be deduced from the calculations that changes in axial forces and bending moments acting on the piles of piled raft foundations are lower than these corresponding to bearing pile foundations. This suggests that piled raft foundations are more effective for the reduction of negative skin frictions on piles. Piled rafts with longer piles can reduce the settlement due to dewatering in case that delayed consolidation does not occur. If the toes of piles locate in the layer which causes delayed consolidation, the settlement of piled rafts would be larger than that corresponding to raft foundations

A modified variational approach for the analysis of piled raft foundation

A modified variational approach is presented to study the behavior of piled raft foundation under vertical loads. The free-body for analysis is a flexible raft isolated from piled raft foundation instead of pile group–soil system or whole pile raft system, which are usually used in other researches. The deflected shape of raft is represented by a function with a set of undetermined coefficients and the interactions between piles and/or the surface loads of soil are evaluated by a simplified approximate analytical solution. The response of the piled raft system is determined by the principle of minimum potential energy. Compared to other rigorous approaches, the present method is computationally efficient and inexpensive. The solutions obtained using the present method of analysis are shown to be in good agreement with other available published results.

小型基礎の原位置実験より得られたパイルド・ラフト基礎の水平挙動

This paper describes the behavior of pile raft foundations obtained from in-situ horizontal loading tests carried on practical but downsized foundation models. Three foundation types, the raft foundation, the pile foundation and the piled raft foundation were tested to clear the behavior of piled raft foundations under horizontal load. Each foundation consists of a concrete block of 2m square with different height, and four steel pipe piles of 48.6mm in diameter in cases of the pile foundation and piled raft foundation. The test results indicate following observations. The final resistance of the piled raft foundation is larger than the summation of those of the raft foundation and the pile foundation. The bending moment of the piles in the piled raft foundation is smaller than that in the pile foundation at same horizontal displacements. In the piled raft foundation, the horizontal load is mainly transferred to the ground through the raft at the beginning of the loading, and is supported more by the piles as the horizontal displacement increases.

Settlement behavior of piled raft foundation on soft ground : Kakurai, M; Yamashita, K; Tomono, M Proc eighth asian regional conference on soil mechanics and foundation engineering, Kyoto, 20–24 July 1987V1, P373–376. Publ Japan: Japanese Society for Soil Mechanics and Foundation Engineering, 1987

Settlement behavior of piled raft foundation on soft ground : Kakurai, M; Yamashita, K; Tomono, M Proc eighth asian regional conference on soil mechanics and foundation engineering, Kyoto, 20–24 July 1987V1, P373–376. Publ Japan: Japanese Society for Soil Mechanics and Foundation Engineering, 1987