氏名　Auttakit　Asanprakit
学位の種類　博士（工学）
学位記番号　博甲第550号
学位授与の日付　平成22年3月25日
学位論文題目　Three-dimensional numerical investigation of pipe jacking method using developed stack pipe model
論文審査委員
　主査　教授　杉本　光隆
　副査　教授　大塚　悟
　副査　准教授　阿部　雅二朗
　副査　准教授　豊田　浩史
　副査　鉄道総合技術研究所 トンネル研究室室長　小島芳之

• 論文目次
• 論文要旨
• 論文審査の結果の要旨

［平成21（2009）年度博士論文題名一覧］ ［博士論文題名一覧］に戻る．

Titlepage　p.i
Acknowledgements　p.ii
abustract　p.iv
Table of contents　p.vi
List of tables　p.ix
List of figures　p.x
Notations　p.xiv
Chapter1　Introduction　p.1
　1.1　General　p.1
　1.2　Research objectives　p.5
　1.3　Organization of the dissertation　p.6
Chapter2　Literature review　p.8
　2.1　A history perspective　p.8
　2.1.1　Pipe jacking in the United State　p.8
　2.1.2　Pipe jacking develops in Europe　p.9
　2.1.3　Pipe jacking technology in Japan　p.9
　2.2　Geotechnical aspects of pipe jacking　p.10
　2.2.1　Subsurface investigation　p.10
　2.2.2　Facestability　p.11
　2.2.3　Surface settlement induced by the tunneling　p.15
　2.3　Jacking load　p.17
　2.3.1　Estimation of frictional force　p.19
　2.3.2　Estimation of face resistance　p.22
　2.4　Numerical implementation on tunneling works　p.25
　2.4.1　Ground displacement aspects　p.25
　2.4.2　Pipe-soil interaction and numerical approach　p.30
　2.5　Pipeline behavior under axial force　p.30
　2.6　Pipe jacking model　p.32
Chapter3　Stack pipe model　p.35
　3.1　General　p.35
　3.2　FE analysis technique　p.35
　3.2.1　Finite element model　p.35
　3.2.2　Phase analysis　p.36
　3.2.3　Ground spring model　p.39
　3.3　Methodology　p.40
　3.3.1　Pipe positioning model　p.40
　3.3.2　Enforced displacement at front end of the pipe　p.44
　3.3.3　Enforced displacement at the outer end of the ground spring　p.45
　3.3.4　Outer end of the machine connection spring　p.48
　3.3.5　Modeling of earth pressure acting on the pipe periphery　p.48
　3.4　Summary　p.49
Chapter4　Simulation on pipeline behavior　p.51
　4.1　General　p.51
　4.2　Pipe jacking project used in the analysis　p.51
　4.2.1　Site description　p.51
　4.2.2　Tunnling measurement　p.54
　4.3　Analysis conditions　p.55
　4.3.1　Analysis area　p.55
　4.3.2　Ground properties　p.56
　4.3.3　Joint spring　p.58
　4.3.4　Frictional resistance　p.60
　4.3.5　Machine connection spring　p.61
　4.3.6　Jacking force　p.61
　4.4　Simulation　p.62
　4.4.1　Pipe behavior under jacking　p.62
　4.4.2　Thrust force and frictional resistance on pipe　p.66
　4.4.3　Moment at joint　p.67
　4.5　Summary　p.68
Chapter5　Parametric study　p.70
　5.1　General　p.70
　5.2　Sensitivity analysis　p.70
　5.2.1　Analysis plan　p.70
　5.2.2　Typical ground profile and analysis conditions　p.75
　5.2.3　Analysis method　p.75
　5.3　Simulation results　p.77
　5.3.1　Influence of coefficient of subgrade reaction　p.79
　5.3.2　Influence of coefficient of horizontal earth pressure at rest　p.79
　5.3.3　Influence of length of straight alignment　p.82
　5.3.4　Influence of lotation angle of the curve　p.85
　5.3.5　Influence of horizontal curve radius　p.85
　5.3.6　Influence of overburden depth　p.88
　5.3.7　Influence of length of pipe　p.89
　5.3.8　Influence of pipe thickness　p.89
　5.3.9　Influence of cushion setting angle　p.92
　5.3.10　Influence of expantion rate of cushion material　p.92
　5.3.11　Influence of over-cutting length　p.95
　5.3.12　Influence of dynamic friction coefficient　p.95
　5.4　Summary　p.98
Chapter6　Conclusions and recommendations　p.99
　6.1　Conclusions　p.99
　6.2　Further works　p.101
References　p.103
Author Publications　p.108
Appendix A　Determination method of βR　p.109
Appendix B　Plotting summary　p.112

In recent years, pipe jacking has been widely recognized by a number of construction projects because this method has less impact on the ground surface, minimizes traffic disruption, and is less time consuming and cost effective. The jacking load is a significant parameter to determine the construction system. This force can be computed by the analytical or empirical calculation models which have been established by various researchers. So far, most of the models do not consider the over-cutting distance, and then pipeline behaviors are not clear. To understand them theoretically, it is necessary to determine the soil-pipe interaction behavior during the construction process.
The purpose of this study is to establish a pipe jacking model based on an existing model and to investigate the pipeline behaviors. The stack pipe model is developed on the concept that the pipes axially connect each other at the both pipe end by 2-node translation springs as the cushion material. Around a pipe and at tunnel face, the 2-node translation springs as the ground reaction are perpendicularly connected. The nonlinear ground reaction curve which was developed previously is used to estimate the earth pressures acting on the pipe periphery. The pipeline positions during jacking process cause the ground deformation around the pipe and in turn the changing of earth pressure. In order to locate a pipe position in the tunnel space, the pipe positioning model is also proposed. The assumption of this model is that a pipe axis is placed on the tunnel axis. For the pipe in curved alignment, a pipe is compulsorily placed with the tunnel wall touching both in-side curve and out-side curve using the adjusted tunnel radius. These assumptions lead to the enforced displacement in all connection springs and the forces are generated in the cushion and the surrounding ground around the pipe periphery. In the Finite Element analysis, phase analysis technique is implemented throughout the pipeline based on the pipe positions, which was previously determined. In this technique the model can be changed from phase to phase. Each element and constraint can be added or removed during the phase change.
Subsequently, the performance of developed stack pipe model is examined by a simulation of the pipe jacking behavior comparing with measured data. The input ground parameters to the finite element analysis were carefully investigated in a preliminary analysis based on empirical values and Terzaghi’s loosening earth pressure. As a result, the simulation shows a good agreement with the observed data. Lastly, the pipeline behaviors under various predominant factors are studied through the sensitivity analysis. Three categories of parameters consisting of the ground properties, tunneling and tunnel geometry, and pipe-cushion characteristics were carried out in this parametric study. According to the simulation results, the most of ground condition parameters induced greater effect than the others parameter category in terms of the alteration of jack force and frictional resistance along the pipeline, especially on the coefficient of subgrade reaction parameter.
All through the research, the stack pipe model was successfully used to simulate the pipe jacking behavior.

本論文は，「Three-dimensional numerical investigation of pipe jacking method using developed stack pipe model（新たに開発した管路解析モデルによる推進工法の3次元数値解析）」と題し，6章より構成されている．
第1章「緒論」では，推進工法を用いて管路を構築するための一般的な施工手順を述べた後，推進管に作用する荷重や推進管の挙動に関する現状の課題の概要を示すとともに，本研究の目的と範囲を述べている．
第2章「既往の研究」では，推進工法の歴史，推進工法により引き起こされる地盤工学上の問題，トンネル構築に関する数値解析法，推進力算定法，推進時の推進管挙動，推進工法に関する数値解析法に関する従来の研究の概要を述べている．
第3章「管路解析モデル」では，新たに開発した，推進管を計画線形に配置するための計算法（推進管配置モデル），推進管継手部のモデル，および，余掘りを考慮できる推進管と地盤の相互作用モデル（地盤反力曲線モデル）について述べた後，これらを統合して推進時の管路全体の挙動を計算するアルゴリズム（管路解析モデル）について述べている．
第4章「管路挙動のシミュレーション」では，第3章で新たに開発した管路解析モデルを検証するため，管路解析モデルを現場データに適用して，管路周辺地盤の挙動，推進管に作用する地盤反力，推進管の挙動，推進管の周面抵抗，推進管の継手部に発生する推進力・曲げモーメントを求め，現場実測値や現場の経験則と比較している．その結果，管路解析モデルは，これらを合理的に表現できることが確認された．
第5章「パラメータスタディ」では，第4章で検証された管路解析モデルを用いて，地盤条件，線形条件，構造物条件，施工条件をパラメータとしたパラメータスタディを行い，これらのパラメータが推進管の挙動に与える影響を明らかにしている．
第6章では，上記で得られた知見をまとめるとともに，今後の課題について述べている．
以上のように，本研究の成果は，推進工法における推進管全体の挙動を理解し，推進管・推力伝達材等の構造物条件や推進力等の施工条件を検討するために有効であり，推進工法の新たな技術開発を可能ならしむるものである．よって，本論文は工学上及び工業上貢献するところが大きく，博士（工学）の学位論文として十分な価値を有するものと認める．