Location

Arlington, Virginia

Date

14 Aug 2008, 2:15pm - 4:00pm

Abstract

This paper presents a case study of blast densification of a site underlain by a loose, saturated, natural sand deposit. Densification was performed to mitigate the risk of liquefaction from earthquake-induced ground vibrations. The work was implemented as part of the design-build construction of the Marine Corps Reserve Training Center at the Westover Air Reserve Base in Chicopee, Massachusetts. Following review of preliminary subsurface data at the site, the contractor retained a team to design and implement ground improvement by blast densification. The team, led by a geotechnical engineering firm, included a blaster, a driller, and a cone penetrometer testing firm. The team performed the analyses, design, implementation and post-densification testing to carry out and document the effectiveness of the blast densification. The paper presents the densification program and comparison of the pre- and post blasting data including settlement results. The project duration including pre-blasting evaluation, design, implementation, and post-blasting evaluation was less than two months. This demonstrates that deep blasting can be successfully implemented as part of fast-track, design-build procurement to execute a complex ground improvement program. It also demonstrates that while the technique is not commonly used, it is sufficiently well understood to provide a flexible and cost effective alternative to the more commonly used ground improvement methods under the right conditions.

Department(s)

Civil, Architectural and Environmental Engineering

Meeting Name

6th Conference of the International Conference on Case Histories in Geotechnical Engineering

Publisher

Missouri University of Science and Technology

Document Version

Final Version

Rights

© 2008 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Earthquake Mitigation by Blast Densification

Arlington, Virginia

This paper presents a case study of blast densification of a site underlain by a loose, saturated, natural sand deposit. Densification was performed to mitigate the risk of liquefaction from earthquake-induced ground vibrations. The work was implemented as part of the design-build construction of the Marine Corps Reserve Training Center at the Westover Air Reserve Base in Chicopee, Massachusetts. Following review of preliminary subsurface data at the site, the contractor retained a team to design and implement ground improvement by blast densification. The team, led by a geotechnical engineering firm, included a blaster, a driller, and a cone penetrometer testing firm. The team performed the analyses, design, implementation and post-densification testing to carry out and document the effectiveness of the blast densification. The paper presents the densification program and comparison of the pre- and post blasting data including settlement results. The project duration including pre-blasting evaluation, design, implementation, and post-blasting evaluation was less than two months. This demonstrates that deep blasting can be successfully implemented as part of fast-track, design-build procurement to execute a complex ground improvement program. It also demonstrates that while the technique is not commonly used, it is sufficiently well understood to provide a flexible and cost effective alternative to the more commonly used ground improvement methods under the right conditions.