Retesting on Tension Fracture of Sand-Packed Container in Small-Size Model Tests
- Yasuyuki Nabeshima (National Institute of Technology)
- Document ID
- International Society of Offshore and Polar Engineers
- The 28th International Ocean and Polar Engineering Conference, 10-15 June, Sapporo, Japan
- Publication Date
- Document Type
- Conference Paper
- 2018. International Society of Offshore and Polar Engineers
- model test, tension fracture, typhoon-induced wave, Sand-packed container, coastal erosion control
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- 7 since 2007
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The sand-packed containers were the geotextile bags filled by dredged sand, which were used for the coastal erosion control. Tension fracture of sand-packed container was occurred in the Miyazaki coast in 2014. The author tried to retest on tension fracture of sand-packed container in the small-size model tests. The small-size sand-packed containers were bent to elucidate tensile fracture mechanism. The tensile strains were measured during model tests. Although the tension fracture was not reproduced in the small model tests, the tensile fracture mechanism was discussed.
Geosynthetic products were widely used as landfill caps and base liner applications, environmental protection under roads and railways, containment structures, dams, canals, ponds, rivers and lakes, coastal and offshore protection. Some of them, which were called as geotube and/or geobag (Pilarczyk KW, 2000), were used to protect shorelines and beaches and to create multifunction artificial reefs. They can be installed to reduce water turbidity and costal erosion, and provide a better beach conditions. They have been used for more than 50 years because they were one of the cost-effective, durable, easy to install and highly flexible methods. They were used for many kinds of shoreline protection, onshore and offshore marine construction projects. The products are a much safer and more natural-harmonized alternative than hard structures such rock and concrete. They have woven or un-woven composite fabric skins, to meet durability and environmental requirements. The geotextile products gradually became larger.
The large size geotextile sand-packed containers filled with dredged soil are buried along the shore line to protect sea shore erosion (Hironaka et al., 2011). Table 1 shows the construction results of the sand-packed container in Japan. Although the number of construction was small in Japan, the sand-packed containers were used for the erosion control against the high sea waves. Some of the geotextile sand-packed containers at the Miyazaki coast, which was the longest construction site in Japan as shown in Table 1, were broken by high waves of the typhoon in 2014. The sand-packed containers were set along the shoreline as shown in Figure 1, which shows the layout of sand-packed containers in Miyazaki coast. The containers were doubletiered as a triangle shape. Ministry of Land, Infrastructure, Transport and Tourism (MLIT) investigated the breakage mechanism of the geotextile sand-packed containers. The reason of the breakage was that a concrete brock under the sandbag penetrated the geotextile as shown in Figure 2. In this study, a series of the model tests were carried out to elucidate the breakage mechanism of geotextile sand-packed containers.
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