Property evaluation of beachrock based on field investigation in Okinawa Island, Japan

Danjo, Takashi; Kawasaki, Satoru

doi:10.1201/b11646-175

Cited by 4 publications

(8 citation statements)

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“…Some beachrocks have been cemented to unconfined compressive strength (UCS) of a few dozen MPa. 15,16) Beachrocks are formed by several mechanisms, including bacterial action. Therefore, application of such formation mechanisms could be used to cement coastal sediments at the site of erosion to artificial rock using local materials (e.g., bacteria, seawater).…”

Section: Introductionmentioning

confidence: 99%

Microbially Induced Sand Cementation Method Using <i>Pararhodobacter</i> sp. Strain SO1, Inspired by Beachrock Formation Mechanism

Danjo

Kawasaki

2016

Mater. Trans.

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To develop an alternative ground improvement technique in coastal areas based on bio-stimulation, we investigated sand cementation using bacteria that have been shown to enhance beachrock formation. We conducted cementation tests using Pararhodobacter sp. strain SO1, a local ureolytic bacteria originating from the sand near beachrock in Okinawa, Japan. Specifically, we attempted to cement sand specimens to unconfined compressive strength (UCS) of several MPa and establish the influence of several test conditions (curing temperature, injection interval of cementation solution, Ca 2+ concentration and sodium malate concentration in the cementation solution, and test period) on the UCS. Column specimens were cemented up to UCS of 10 MPa after 28 days under the conditions (curing temperature; 30°C, injection interval; 1 day, Ca 2+ concentrations in cementation solution; 0.3 M). Multiple regression analysis showed that the relevant conditions for UCS were test period, D (days), and Ca 2+ concentration of the cementation solution, C ca (M). The prediction formula for UCS, q ud (MPa), was experimentally determined to be q ud = 48.3C ca + 0.456D ¹ 19.51. Overall, the results of this study will contribute to the application of a new technique for coastal sand improvement and bio-stimulation.

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Section: Introductionmentioning

confidence: 99%

Microbially Induced Sand Cementation Method Using <i>Pararhodobacter</i> sp. Strain SO1, Inspired by Beachrock Formation Mechanism

Danjo

Kawasaki

2016

Mater. Trans.

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“…Beachrock at Tiruchendur, India, mainly consists of Ca. In contrast, the beachrock in Vattakottai, India, is mainly Si-and Al-rich and that in Kanyakumari, India, is mainly Fe-and Ti-rich (Danjo and Kawasaki, 2012b) where Bangladesh is Si rich (Fig. 2).…”

Section: Beachrock Propertiesmentioning

confidence: 99%

“…Beach of Bangladesh located between 20 0 35 / N to 22 0 50 / N latitude and 89 0 06 / E to 92 0 21 / E longitude. But there is no relation between the formative age of beachrock and latitude (Danjo and Kawasaki, 2012b).…”

Section: Beachrock Propertiesmentioning

confidence: 99%

Formation of artificial beachrock towards inhibit of coastal erosion in Bangladesh: a review

Khan

Kawasaki

2016

JGS Special Publication

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Erosion in the coastal area of Bangladesh is a big point of concern. The present study was conducted to find out the protective measure from coastal erosion in Bangladesh as well as evaluate the prospects of the formation of artificial beachrock. This study was conducted based on literature survey of related works. In the coast of Bangladesh, average recession through erosion will occur 0.87m due to per 1cm sea level rise. Beachrock as well as artificial beachrocks have the potentiality to prevent such coastal erosion. Beachrock is a type of sedimentary deposit that generally occurs on the tropical and subtropical beaches as a result of intertidal lithification of loose beach sands and gravels by carbonate cementation. Beachrock in the world differs by their chemical composition but it composed mainly of CaCO 3 , SiO 2 and Al 2 O 3. Usually, beachrocks are formed by the cementation of CaCO 3 precipitation with the influence of seawater and/or seawater evaporation as well as surface microorganisms. From the knowledge of natural beachrock formation as well as sand properties, in the future, it may possible to manufacture artificial beachrocks similar to beachrocks for erosion control purposes in Bangladesh.

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“…Coastal erosion has been studied in Viet Nam [3]; Bangladesh [4], [14], [17]; Malaysia [22]; Indonesia [33]; Sri Lanka [25]; India [12], [18]; China [2], Thailand [29] and Japan [6], [8], [16], [19] which is indicated in the Fig. 1.…”

Section: Coastal Erosion In Asiamentioning

confidence: 99%

“…The geotextile tube technology is mainly used for flood and water control, but they are also used to prevent beach erosion as well. In additionally, considering the use of artificial rock to preserve such submerged-looking islands above sea level, Danjo and Kawasaki [6], [8] conducted several studies in Okinawa and Ishikawa, Japan. They found sufficient information to build artificial beachrock.…”

Section: Introductionmentioning

confidence: 99%

Combination Technology of Geotextile Tube and Artificial Beachrock for Coastal Protection

Imran¹

2017

GEOMATE

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ABSTRACT:In recent years, traditional forms of river and coastal structures have become very expensive to build and maintain, because of the shortage of natural rock. Therefore, the materials used in hydraulic and coastal structures are changing from traditional rubble and concrete systems to cheaper, sustainable, and ecofriendly materials and systems such as artificial rock, gabion, slags, geosynthetics, and so on. Moreover, shorelines are being continually eroded by the wave action of the sea, and the river and coastal structures are frequently damaged by both anthropogenic and natural causes such as over wash and storm. How to deal with eroding coastal problems is a main topic of this article. Recently, artificial beachrock and geotextile tube technology has changed from being an alternative construction technique and, in fact, has advanced to become the prime solution of choice. Therefore, the objectives of the present study is to find out the feasibility to protect coastal erosion in Asia along with using artificial beachrock and geotextile tube technology in a cheaper, sustainable and eco-friendly way.

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Property evaluation of beachrock based on field investigation in Okinawa Island, Japan

Cited by 4 publications

References 0 publications

Microbially Induced Sand Cementation Method Using <i>Pararhodobacter</i> sp. Strain SO1, Inspired by Beachrock Formation Mechanism

Microbially Induced Sand Cementation Method Using <i>Pararhodobacter</i> sp. Strain SO1, Inspired by Beachrock Formation Mechanism

Formation of artificial beachrock towards inhibit of coastal erosion in Bangladesh: a review

Combination Technology of Geotextile Tube and Artificial Beachrock for Coastal Protection

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