Kenichi Kaneko

DEVELOPMENT OF BUILDING METHOD OF A LARGE TUNNEL BY INTEGRATED SMALL SHIELDS

We are developing a new technique of building a large tunnel by piling up small shield tunnels, as a way ofmaking underpasses at the intersection between a railway and a roadway, or between two roadways. A tunnel is divided into several sections as if mouthpiece of a harmonica and each section is built individually, and then they are connected together. The miniaturization of machines makes it possible to build a tunnel which is shallow ground. Moreover, during the execution it does not significantly damages the ground , because of its cross-sectional structure. Since they are built partly, it eases traffic congestion. It is also suitable for a long distance or a curve-lined section.

A NEW SHIELD SUITABLE FOR LARGE-SECTION LONG-DISTANCE TUNNELING

The length of shield tunnel i ng h as been on the increasei n recent years, and long-distancetunneling with a large-section shield exceeding 10 m indiameter is likely to increase inthe near future. Taking advantage of the fact that a large cross section is involved, the a uth ors have developed an eccentric multi-axis shield tunneling machine that has six fan-shaped cutters. Each cutter has its own drive system and is capable of being retracted into a housing that has the same shape as the cutterhead located in the shield. This paper reports on a three-dimensional flow analysis of sl urry in the chamber and shows that use of segmental cutters improves flow.

STUDIES ON DESIGN METHODS FOR VERTICAL SHAFTS CONSTRUCTED WITH CONTINUOUS VERTICAL-HORIZONTAL EXCAVATION SHIELDS

立坑と横坑を連続して掘進するシールドが実用化されはじめたのに伴い, 新工法によって構築される立坑の設計法を確立しておく必要性が生じている. しかし, 従来の立坑設計に用いられている手法を用いると重厚な構造となり, 新工法の特徴を生かせない. 本研究では, セグメントで構築される立坑部については, 深礎工事で用いられている手法を常時および施工時に適応し, 地震時については通常のシールドトンネルで用いられている動的解析手法を適用した. 立坑底部については3次元FEMにより解析を繰返し, 最適な解析モデルを設計した. これらの設計例により, 新工法による立坑構造が経済的な部材で成り立つことを述べる.