地震による管路被害予測の確立に向けた研究概要
東日本大震災により水道施設は、東北から関東に至る広い範囲で甚大な被害を受けた。
今後我が国においては、東海地震、東南海・南海地震や首都直下地震等の発生が現実味を帯びており、水道においても、これまでの震災対策を抜本的に見直した危機管理の対策を講じることが喫緊に求められている。
このような背景により当センターでは、水道管路の耐震化促進に寄与するため、平成２３年度から特別研究事業として、金沢大学の宮島昌克教授を委員長とした「地震による管路被害予測の確立に向けた研究検討委員会」を設置し、東日本大震災による管路被害の状況から得られた知見を基に、新たな管路被害予測式を確立した。
従来の予測式は、管種・継手、口径、管が布設されている微地形と地震動の最大速度から、管路の被害率（件/km）を推定するものであった。しかし、液状化が発生した千葉県浦安市及び旭市や宮城県仙台市に多くみられる人工改変地では、実際の被害が従来の予測式で求めた被害率よりも高くなったことから、液状化の可能性がある地域について、新たな予測式を提案したものである。また、液状化の可能性がない地域においては、宮城県旧石巻市及び登米市における被害の検証結果を踏まえ、従来の予測式を用いることとした。
この予測式は、耐震化の優先順位を決めるにあたり、中小も含めた水道事業体に広く活用してもらえるよう、マッピングシステム等が整備されていない事業体でも利用できるものとなっている。

本報告書は以下の内容で構成されている。
1. 研究目的と体制
2. 研究概要
3. 地震による管路被害予測式の開発
4. 地震による管路被害予測式の検証
5. 管路被害予測式の活用

Research on Predictive Equation for Earthquake Damage to Pipelines
Outline
The Great East Japan Earthquake of March 2011 inflicted critical damage on drinking water
pipelines in extensive areas from Tohoku to Kanto regions. In the wake of this devastating event, watermanagers and policymakers are expected to urgently address seismic weaknesses of the current water
system and develop effective mitigation and response activities and strategies.
Aiming to help water utilities better prepare themselves against potential earthquake hazards infuture, Japan Water Research Center has set up a research committee with Dr. Masakatsu Miyajima,
Professor of Kanazawa University, as its chair, and has developed a new predictive equation to estimate
potential damage to water pipelines under major earthquakes.
The conventional predictive equations developed by JWRC estimate the number of leaks, breaks, orother types of failure per kilometer of pipeline based on the liquefaction threat, micro topography, andpeak earthquake velocity at specific locations. The most important feature of the newly developed
equation is that it gives greater weight to liquefaction-caused ground failure effect and employs morerefined method to calculate its impact. This is because the pipelines in severely liquefied zones—mostly
located in Urayasu City and Asahi City in Chiba Prefecture and Sendai City in Miyagi Prefecture—werefound to have suffered more extensively than the conventional equations had indicated. On the otherhand, as for liquefaction-free zones, we will continue to use conventional equations with proper updates
made based on the observed damage in the former Ishinomaki City and Tome City of Miyagi Prefecture,
which were affected by the earthquake but experienced no liquefaction.
The newly developed predictive equation is designed in the way that water utilities of any size canuse to better prioritize their anti-earthquake planning and activities. The utilities considered include
smaller ones which may not be equipped with more sophisticated operational tools such as Mapping
System that can assist in estimating pipelines’ vulnerability.

This report consists of the following chapters:
1. Research Purposes and Structures
2. Research Summary
3. Development of Predictive Equation for Earthquake Damage to Pipelines
4. Verification of Predictive Equation for Earthquake Damage to Pipelines
5. Application of Predictive Equation for Earthquake Damage to Pipelines地震による管路被害予測の確立に向けた研究
報告書目次

1. 本研究の目的と研究体制 ··························································································11.1 本研究の目的 ········································································································ 11.2 研究体制 ·············································································································· 22. 本研究の概要 ·········································································································32.1 管路被害予測式の検証 ···························································································· 32.2 管路被害予測式（改訂版）の提案 ············································································· 33. 地震による管路被害予測式の開発 ···············································································53.1 研究方法 ·············································································································· 53.2 研究結果 ·············································································································· 64. 地震による管路被害予測式の検証 ···············································································94.1 検証の目的 ··········································································································· 94.2 検証の方法 ··········································································································· 94.3 管路被害について ································································································ 104.4 検証結果 ············································································································ 284.5 考察 ·················································································································· 40
5. 管路被害予測式の活用 ··························································································· 48
5.1 予測式の解説 ······································································································ 48
5.2 予測式の活用例 ··································································································· 55
参考文献 ················································································································· 64