Location

New York, New York

Session Start Date

4-13-2004

Session End Date

4-17-2004

Abstract

Two, 42-meter diameter, 12.2 meter high (100,000 barrel) above ground jet fuel tanks are currently under construction by the Japan Engineering District (JED), U.S. Army Corps of Engineers for the Defense Logistic Agency (DLA) at Marine Corps Air Station (MCAS) Iwakuni. This presentation is a case study of the installation of Sand Compaction Piles (SCP’s) and surcharge at MCAS Iwakuni. The geology below the tanks consists of poorly behaving liquefiable silty clays that can affect the bearing capacity of the loaded tanks. The site was formerly a marsh area filled with various debris and construction refuse and then covered with fill material. The elevation of the original marsh area is at sea level, and corresponds to the elevation of groundwater. The near surface soil consists of 6 to 12 meters of loose, liquefiable sand. Underlying this sand layer is 15 to 20 meters of soft, compressible clays and silts. A medium to dense sand and gravel underlies the soft clays and silts. The Iwakuni Faults, which are active faults, are located near MCAS Iwakuni. These faults are classified as Class B under the Japanese Standard, which is medium level in magnitude. The distance from MCAS Iwakuni to these faults is approximately 8 km. Foundation treatments to include SCP’s, Sand Drainage Piles (SDPs) and surcharge mounds are used to improve foundation conditions. SCPs are not a deep foundation as in a typical pile, but rather a method for dynamically densifying loose sands. They have used extensively in Japan for many years to decrease the potential for liquefaction damage. Effectiveness of the SCPs in densifying the surrounding soils is determined by measuring the “N” value determined from a Standard Penetration Test taken in the area between the SCPs. The clay layer was consolidated using a soil surcharge. Percent consolidation was determined using vibrating wire piezometers.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Fifth Conference

Publisher

University of Missouri--Rolla

Publication Date

4-13-2004

Document Version

Final Version

Rights

© 2004 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Apr 13th, 12:00 AM Apr 17th, 12:00 AM

Foundation Treatments Using Sand Compaction Piles and Surcharge Loading Marine Corps Air Station Iwakuni, Japan, A Case Study

New York, New York

Two, 42-meter diameter, 12.2 meter high (100,000 barrel) above ground jet fuel tanks are currently under construction by the Japan Engineering District (JED), U.S. Army Corps of Engineers for the Defense Logistic Agency (DLA) at Marine Corps Air Station (MCAS) Iwakuni. This presentation is a case study of the installation of Sand Compaction Piles (SCP’s) and surcharge at MCAS Iwakuni. The geology below the tanks consists of poorly behaving liquefiable silty clays that can affect the bearing capacity of the loaded tanks. The site was formerly a marsh area filled with various debris and construction refuse and then covered with fill material. The elevation of the original marsh area is at sea level, and corresponds to the elevation of groundwater. The near surface soil consists of 6 to 12 meters of loose, liquefiable sand. Underlying this sand layer is 15 to 20 meters of soft, compressible clays and silts. A medium to dense sand and gravel underlies the soft clays and silts. The Iwakuni Faults, which are active faults, are located near MCAS Iwakuni. These faults are classified as Class B under the Japanese Standard, which is medium level in magnitude. The distance from MCAS Iwakuni to these faults is approximately 8 km. Foundation treatments to include SCP’s, Sand Drainage Piles (SDPs) and surcharge mounds are used to improve foundation conditions. SCPs are not a deep foundation as in a typical pile, but rather a method for dynamically densifying loose sands. They have used extensively in Japan for many years to decrease the potential for liquefaction damage. Effectiveness of the SCPs in densifying the surrounding soils is determined by measuring the “N” value determined from a Standard Penetration Test taken in the area between the SCPs. The clay layer was consolidated using a soil surcharge. Percent consolidation was determined using vibrating wire piezometers.