小田 和広

排水距離が長くなると擬似過圧密粘土の圧縮曲線が緩くなることを数値解析により証明した。

関空洪積粘土の長期圧密挙動に対する一次元圧密モデルの提案と適用性の検証。

新潟県中越地震における道路施設の被害と復旧との関係について。

An elasto-viscoplastic one-dimensional consolidation model is proposed to express a time dependent consolidation behavior of "quasi-overconsolidated clays" in stress level range from the current overburden pressure to slightly over the consolidation yield stress. The numerical simulation of a series of long-term consolidation tests for Ma3, Pleistocene clays in Osaka Bay, is carried out in which the model proposed is applied. The applicability of proposed model is confirmed through a comparison between the experimental and analytical results.

An elasto-viscoplastic one-dimensional consolidation model was proposed for quasi-overconsolidated clays in stress level range from the current overburden pressure to over the consolidation yield stress, followed by confirming its applicability to the long-term consolidation behavior of Pleistocene clays of Osaka Bay through numerical simulations of a series of long-term consolidation tests. Then, a series of numerical simulations was carried out to investigate the effect of drainage path length on the consolidation behavior of quasi-overconsolidated clays in stress level less than the consolidation yield stress. As the results, it was concluded that the proposed model was one of available effective techniques for predicting the long-term consolidation behavior of the quasi-overconsolidated clays.

PBDが打設された模型地盤の圧密実験とその数値シミュレーションについて。

SCP改良地盤の改良特性に及ぼす土被り圧の影響 について。

大阪湾の洪積粘土の一次元圧密モデルの提案について。

大阪湾の海底地盤データベースに基づく地盤特性の分析と関西空港島の建設プロジェクトの紹介。

下負荷面理論を導入することにより、擬似過圧密粘土の二次圧密挙動を再現している。

関西国際空港の空港施設に対する不当沈下をはじめとする軟弱地盤の問題とその対策について。

PBD工法における換算径に関する数値解析。

In this paper, the damaged performance of bored piles in the 1995 Kobe Earthquake is overviewed, followed by their remediation methods and works. Then, the fundamental seismic performance of piles was discussed through data of centrifuge model tests and numerical simulations. Finally, the conventional revised aseismic design practice on bored piles in Japan was briefly presented. As the results, it was pointed out that the lateral deformation of ground with liquefaction caused more severe damages to the pile foundations, and that some engineering issues for sophisticating the practical aseismic design were still remained for further researches, showing the Outline of the conventional aseismic design method for the pile foundations subjected to lateral deformation of ground with liquefaction.

ソイルネイリングによって補強された掘採工事におけるネイリング間の変形挙動に及ぼすネイリングの直径と間隔の影響を数値シミュレーションによって明かにした。

サンドドレーンが打設された圧密圧密時間の推定方法について数値シミュレーションを通じて検証している。

立坑掘削における土留め壁背面地盤の３次元変形挙動に関する数値を解明。

神戸沖不撹乱沖積粘土に対しひずみ経路制御ミニ三軸試験を実施し降伏曲面を推定するとともに、せん断挙動に及ぼす圧密時のひずみ増分比の影響について考察した。

大阪湾の埋立地における長期圧密沈下挙動と洪積粘土の長期圧密挙動について考察した。

PBDの形状の換算径の提案とそれを使った圧密速度の計算方法の提案。

ソウル市おいてネイリング工法が適用された掘削工法の３次元的変形挙動の再現。

PBD打設の際のPBDの配置と圧密速度の関係に関する数値解析。

アルミ積載棒を利用した模型地盤の掘削に対するソイルネイリング補強効果に関する実験的研究。

ソイルネイリングによって補強された鉛直のり面掘削に関する解析的研究。

The 1995 Hyogoken-Nambu Earthquake had caused severe damages to many structures in the bay area. The damage of the shore structures were due to the occurrence of the liquefaction. In this paper, focusing on the sheet pile quay wall, which is a typical type of shore structures, the seismic behavior of the structures is discussed when the liquefaction occurs, by applying the dynamic response analysis and the simplified prediction method which was proposed by the authors. Firstly, based on the case study by the dynamic response analysis, the influence of the input earthquake motion on the residual deformation of sheet pile quay wall is discussed. As a result, It is confirmed that the residual horizontal displacement of top of sheet pile depends on the maximum horizontal acceleration and the degree of stiffness of back fill. Secondly, the applicability limit of the simplified prediction method were discussed by comparing with the dynamic response analysis. The simplified analysis is applicable as a prediction method for seismic behavior of sheet pile quay wall by considering the influence of the semi-liquefaction.

大阪湾洪積粘土の長期圧密試験を実施するとともに現場での長期沈下の実測挙動との関連性について考察した。

立坑掘削時の土留め壁背面地盤の沈下特性に対する三次元効果の影響について数値シミュレーションによって考察した。

数値解析と実測結果を有機的に組み合わせることにより、地盤工学的問題を解決することを目的とした拡張TYPE-C予測手法を提案するとともにその意義を考察した。

低置換率のSCP改良地盤に関する模型実験とその数値解析。

兵庫県南部地震を受けての海岸構造物の変形量の推定に関する解析的研究。

安治川水門に代表される大規模ケーソン構造物の地震時安定性について。

In this paper, a full-scale field vertical loading test of cast-in-place bored piles was reproduced through an elasto-plastic finite element analysis. The applicability of the numerical analysis was confirmed through a comparison between analytical and measured results. A series of numerical analyses, in which the pile diameter was chosen as a variable, was carried out in order to investigate the effect of pile diameter on bearing resistance of cast-in-place bored pile. Through the analyses, the mechanical characteristics of skin friction around pile shaft and base bearing resistance at pile tip were elucidated.

Recently, the plastic board drain method has widely been used in Japan for accelerating the consolidation of soft clay ground. The accurate prediction of consolidation behavior of the ground improved by plastic board drains, however, is very difficult because the consolidation characteristics of the improved ground have not sufficiently been elucidated. The shape of drains is one of the most important factor which affect the consolidation characteristics of the improved ground. In this paper, a series of model consolidation tests of soft clay ground improved by plastic board drain was carried out, in order to investigate the effect of both plastic board width and stress level on consolidation characteristics of the improved ground. As the results, behaviors of both settlement and excess pore pressure dissipation were elucidated. Also, the non-uniform distribution of water content in the model ground is obtained. It was concluded that the consolidation time became shorter in cases of wider plastic boards. Finally, through the comparison between experimental consolidation behaviors and Barron's theoretical ones, the validity of this experimental study was estimated.

A series of model consolidation tests and their numerical simulations were carried out, in order to elucidate the mechanism and performance of clay-sand column system. The availability of the numerical simulations was quantitatively confirmed through the comparison between analytical and experimental results. Both mechanical behaviors of sands and clays in clay-sand column system were elucidated, based on the numerical simulations. Also, the mechanical interaction between sands and clays was discussed. Finally, another series of numerical simulations was carried out, in which both replacement area ratio and applied pressure were chosen as variable parameters. Their effects on stress sharing ratio and settlement reduction factor were discussed, from the viewpoint of mechanical non-linearity of sands and clays.

In Osaka Bay of Japan, a number of large-scale reclamations has been executed. The settlement by those reclamations is serious enough to be discussed. The compression of the stiff Pleistocene clay deposits causes the half of this settlement, and it makes the quality control of the reclaimed lands very difficult. The residual settlement of Pleistocene clay deposits after the completion of reclamation cannot be avoided because of the difficulty of ground improvement for them. According to the geological history, the Pleistocene clays in Osaka Bay are thought to be the normally consolidated aged clays that exhibit apparently overconsolidated behavior although this is due to the nature of quasi-overconsolidation. This makes the problem of settlement more complex. In this paper, the characteristics of the long-term settlement of the reclaimed lands at Osaka Port are discussed based on the measured data, and a series of long-term consolidation tests is done to assess the property of the quasi-overconsolidated Osaka Bay Pleistocene clays.

大阪湾の埋立地における長期沈下挙動について考察し、埋立地が陸化した時点付近から生じることを明らかにした。

To discuss the shear behavior of clay under the real element test condition, the authors carried out a conventional drained test and two Blinds of drained test simulations for a remolded clay by using the strain path controlled mini-triaxial testing apparatus. In the simulation A, the excess pore pressure was kept-zero during compression and in the simulation B, the strain path;was controlled along that recorded in the conventional drained test. The drained test simulation A could sustain the uniformity of water content distribution within specimen and the volumetric strain during compression was smaller than that in the conventional drained test, because of the uniform water content distribution. In the simulation B, the negative excess pore pressure appeared during compression because of the over drainage. As a conclusion, the shear behavior of clay under the real element test condition can be investigated by the drained test simulation A.

低置換率のSCP改良地盤における力学メカニズムの解明。

For the purpose of sustaining stress and strain uniformity in a clay specimen, the authors have developed a strain path controlled mini-triaxial test apparatus, followed by comparing shear behaviors of specimens and water content distributions within specimens between strain path controlled test and conventional undrained/drained tests. As the results, it was demonstrated that the strain path controlled test was a real element one. Furthermore, the relationship between the strain path dependent shear behavior to water content distribution within a specimen was elucidated.

低圧力から高圧力下における大阪湾洪積粘土の時間依存的変形挙動の実験的研究。

広範な圧力範囲における洪積粘土の圧密試験の結果について。

小型供試体を利用した三軸試験機とその実務への適用について考察。

For the purpose of sustaining stress and strain uniformity in a clay specimen and controlling arbitrary strain paths, the authors have developed a strain path controlled mini-triaxial testing apparatus, in which a small size specimen (22.5 mm in diameter and 45 mm in height) is used, In this paper, to investigate shear behavior of day, the authors carried out a series of strain path controlled mini-triaxial test using remolded kaolin clay, As a result, strain path dependent shear behavior is observed, which is quite different from that of drained or undrained triaxial test, That is, as increasing the strain increment ratio R between axial and volumetric strains, the maximum deviator stress increases while the maximum excess pore pressure decreases, and the effective stress path shifts off the failure line, Furthermore, the strain path dependent shear behavior of remolded clay is discussed, following that it is closely related to strain increment ratio and dilatancy.

兵庫県南部地震における構造物基礎の損傷についての報告。

SCP改良地盤の模型実験の再現解析を通じた再現解析の妥当性の検証を行った。

ミニ３軸試験の不撹乱粘土への適用性の確認を行った。

阪神淡路大震災における構造物基礎の被害調査のレポート（英語版）。

阪神淡路大震災における構造物基礎の被害調査のレポート。

ミニ三軸圧密試験の紹介とそれによる自然堆積粘土の力学パラメータの決定方法。

一連のミニ三軸試験により得られたせん断特性を通じた粘土の弾塑性パラメータを提案するとともにそれを泉州沖粘土に適用した。