Mechanisms of pipe flow of liquerfied sand its control

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K14027
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Geotechnical engineering
• Research Institution: Saitama University (2016-2017); The University of Tokyo (2015)
• Principal Investigator: UCHIMURA Taro 埼玉大学, 理工学研究科, 准教授 (60292885)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 液状化 / 砂質土 / 管内流れ / 下水管 / 模型実験

Outline of Final Research Achievements

In the 2011 Great East Japan Earthquake, the sewage systems had serious damages that large amount of liquefied sand flowed into the pipes for long distances. Pipes with small diametes in house areas were considered as one of possible routes for the sand to flow into the pipe system. In this study, the flow of liquefied sand through a pipe with small diamter was simulated by model tests.
As a results, the liquefied sand did not flow so much after the cross section of the pipe was filled with sand. The total stress measured along the inner surface of the pipe showed significantly large values, which suggests clogging of the sand in the pipe. Therefore, it may be difficult for the liquefied sand with a large amount through pipes with small diameter.
In addition, the inner total stress showed high values and low vaules alternately with periods of several seconds. Such behaviour is never observed with ordinal flued like water, and is specific with the granular materials.

Free Research Field

地盤工学