A geotechnical approach to lifeline LCC reduction: Compliant stabilisation and long-term behaviour

2014 Fiscal Year Final Research Report

• Project/Area Number: 25870007
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Civil engineering materials/Construction/Construction management; Geotechnical engineering
• Research Institution: Hokkaido University
• Principal Investigator: NISHIMURA Satoshi 北海道大学, 工学(系)研究科(研究院), 准教授 (70470127)
• Project Period (FY): 2013-04-01 – 2015-03-31
• Keywords: 泥炭 / パイプライン / 沈下 / 長期管理

Outline of Final Research Achievements

Buried pipelines in peat ground have been found to suffer long-term subsidence, necessitating expensive maintenance work. This problem was confirmed by analysing 18-year records of pipeline subsidence and correlating them with peat layers distribution. One of the suspected causes of the subsidence is an effective stress increase due to replacement of light peat by heavier sandy fills around the pipelines. The detailed mechanisms behind the subsidence were studied by performing long-term model tests and elasto-plastic finite element analysis, and were interpreted and explained with the aid of the deformation characteristics of peat established by long-term triaxial tests. As countermeasure, a possibility of adopting granularised stabilised soil as a fill around the pipeline was explored. Its small unit weight and low subgrade stiffness was found to be advantageous in preventing long-term subsidence as well as alleviating forced straining due to any remaining differential settlement.

Free Research Field

地盤工学