同一立坑から2工区のシールドを二方向同時掘進:東京都水道局　多摩南北幹線(第一·第二工区)

摘要

Tama Nanboku Water Main (tentative name) is a 2,000mm diameter water pipe starting at the Higashi-Murayama water purification plant to the Haijima water station extending 15.6km. Currently, it is divided into six construction lots, and tunnel building and piping are carried out using the shield TBMs. During installation, we had many restrictions such as ensuring the shaft site, and adjusting the construction process according to the neighboring lot. Moreover, at the actual construction site, strict construction management and thorough implementation of a safety management system to prevent any accidents were very important. This article discusses the simultaneous two-way launch from one launch shaft in Construction Lot 1 and 2 of Tama Nanboku Water Main, and introduces construction, safety management measures, and accident prevention measures at the launch when multiple contractors carried out multiple tasks in the shaft.%多摩南北幹線(仮称)は，東村山浄水場を起点として拝島給水所に至る延長15.6km，口径2,000mmの送水管である.現在，6工区に分割してシールド工法によるトンネル築造，配管を行ってぃる. 整備にあたっては，立坑用地の確保や隣接工区との工程調整など，多くの制約条件が存在する.また，実際の施工現場では，綿密な施工管理と徹底した安全管理体制の整備による事故防止が重要となる. 本稿では，多摩南北幹線の第一工区と第二工区における両発進立坑からの二方向同時掘進につぃて取上げ，複数の受注者が立坑内で並行作業を実施する際の施工および安全管理対策，初期掘進時における事故防止対策などについて紹介する.