Stacking of sandbags combined with the use of ground improvement technology (for basic restoration and reinforcement/restoration)

ENTRY DATE: 25.12.2014 | LAST UPDATE: 25.12.2014

CATEGORIES:

  • Disaster Prevention
  • Applicable to any disaster (Hard measures)

TECHNOLOGIES MATURITY:

Demonstration phase and ready for application (pilot study has been completed, with good results, so technology is deemed to be at mature level)

Technology Owners:

National Institute for Rural Engineering

Needs Address

  • The need for reinforcement measures for the flood and heavy rain at dikes and roads.
  • It is applicable for full-scale restoration and reinforcement restoration after the disaster, and it is also for the need for shoreline defense.

Adaptation effects

It is also applicable to protect the dikes and roads from the flood or to prevent inland slope disaster.

Overview and Features

  • Sandbags are cloth bags filled with sand, and are used as a convenient way to block the movement of water and sediment. A layered structure created by stacking sandbags maintains stability and can hold back water erosion and failure of riverbanks.

    Figure: Basic concept of stacked sandbag method
     
  • The protection of roads using sandbags is not a new technology, but the feature of this technology is the use of sediment, cement and jute, which is one of the strongest natural fibers, as a hardening material for the filler in the bags, with the purpose of ground reinforcement. Jute is produced in India, Bangladesh and other countries, and is also used in jute bags to hold grains; it is easy to obtain in developing countries. This is “hybrid ground technology” due to the novel combination with technology for ground improvement. This is the new method that also has improvement technique for ground.
    Example of sandbags 
    ① Geosynthetic bags: 
    The material of “geosynthetics” is costly, but is it is durable in soil, and the use of “tails” and “wings” attached to sandbags enables the creation of an interconnected structure with the embankment and adjacent sandbags. 
    ② Jute bags:
    As mentioned above, these are also readily available at low cost in developing countries. 
  • Merits of the stacked sandbag method:
    ① Can be installed by human power, without advanced construction technology or special construction equipment 
    ② Can make use of local materials 
    ③ Construction process is simple, technology can be easily transferred.
    ④ Can create a strong structure with a well-compacted embankment. 
    ⑤ Can create a steep embankment and reduce amount of land needed for construction, which makes this technology useful in places where land acquisition is difficult.

Cost

Initial costs: 
Local materials are used to make sandbags, so cost is lower compared to conventional techniques. However, depending on the quantity of the cement, the initial cost seemed to be slightly risen for ground improvement technology (solidification by mixing little quantity of cement).

Ease of maintenance

  • The use of jute for sandbags makes maintenance relatively easy.
  • This technology can be repaired by local people timely.

Technology performance

  • Even if not used for permanent restoration and reinforcement, this technology has significantly better durability and other performance features compared to conventional sandbags.
  • If high durability material used and soil covered to protect from ultraviolet, sandbags can be applicable as full-scale restoration and reinforcement restoration.

Considerations

  • For technology transfers, adequate coordination is needed with local technicians regarding technology for strengthening the filling material. 
  • There is a need to address the fact that this technology will be slightly more costly than conventional sandbags. 

Co-benefit, suitability for developing countries

  • This technology has high value-added. The co-benefits are therefore deemed to be excellent. 
  • Local people are personally available to build the roads or dikes having extremely high durability as no special techniques needed and also it can be built by manpower.
  • It is also possible to build substantial dikes and roads against the earthquakes.

Information Resources

  • Y.Mohri,K.Matsushima,S.Yamazaki,T.N.Lohani,F.Tatsuoka,T.Tanaka: New direction for earth reinforcement:disaster prevention for earthfill dams. Geosynthetics International, p246-273, 2009/09
  • Kenichi Matsushima, Yoshiyuki Mohri, Katsuhiko Nakazawa, Kouji Yamada, Toshikazu Hori, Mitsuru Ariyoshi: The pilot test of countermeasure against wave erosion for road embankment in Bangladesh, Geosynthetics Engineering Journal, 25, pp. 99-106, 2010.
  • Yasuhara, K. and Juan, R.: Geosynthetic-wrap around revetments for shore protection, Geotextiles and Geomembranes, Vol. 10, No. 1, 1-12, 2007.4.