Location
New York, New York
Date
13 Apr 2004 - 17 Apr 2004
Abstract
About 20 million gallons of liquid hazardous and toxic industrial wastes were disposed at the Hardage Site, about 35 miles southsouthwest of Oklahoma City, from 1972 to 1980. Following Superfund designation of this site by the EPA, identification of a few hundred companies as Potentially Responsible Parties, and a court ordered excavate, incinerate, and re-entomb remedy for its remediation, many of the companies joined to form the Hardage Site Remedy Corporation (HSRC) for implementation of design, construction, operation, and maintenance of the facility. With the aid of a panel comprised of experts in the disciplines relevant to contaminated site remediation, an alternative remedy was developed and shown to be both more protective of the environment and more cost effective than the EPA remedy. The HSC was successful in its lawsuit for adoption of its plan. The key geotechnical components of the remediation included (1) demonstrating that the clay-shale formation underlying the site was intact and not susceptible to adverse interactions with the liquid wastes, thereby justifying the use of this formation as a bottom barrier; (2) determining the hydraulic properties of the soil formations above the bottom barrier and analysis of the NAPL and soluble contaminant transport, (3) the construction of a 2700 ft long, 67 ft deep (on average), and 3 ft wide gravel-filled trench, keyed into the bottom barrier, that serves to intercept wastes that migrate and diffuse from the buried waste liquid sources, and which would otherwise flow offsite, and (4) the design and construction of a low permeability composite cap over the disposal area. In the second project described in this paper, plans for the redevelopment of a large rail yard area in Sacramento, CA were significantly impacted by the presence of a variety of soil contaminants in potentially liquefiable sandy soils. A portion of the approved remedy for this site included consolidation of contaminated soil in a fully lined and capped containment structure (know as the “rail berm”, or simply the “berm”) that would ultimately be used to provide secondary flood protection and would be used to elevate up to seven sets of rail tracks above grade. This project was significant in that it essentially represented construction of a waste containment facility in the middle of a major metropolitan area. As a result, both environmental and seismic safety issues had significant impacts on design and considerable subsurface investigation, laboratory testing, and engineering analyses were completed to address these issues. Perhaps the most noteworthy geotechnical issue for this project was subsurface soils along the alignment of the planned containment berm that were subject to liquefaction. One of the key aspects towards securing approval of this project was frequent communication with a number of regulatory organizations and project team members (both informally and through regular project meetings) to discuss the rationale for project concepts, planned investigatory procedures, the results of field and laboratory studies, and the results and implications of the design analyses. Through this process, early regulatory agency “buy-off” on project concept minimized the delays that frequently plague environmental projects. Notwithstanding the significant costs associated with a planning, analysis, and design process that addressed redevelopment of a 240 acre former industrial area and despite securing preliminary regulatory approval for construction of the containment structure, the project sponsor opted to terminate the project in favor of contaminated soil excavation and off-site disposal. The principal reasons for the change were not costs, geotechnical issues, or regulatory or public acceptance. Rather, land use plans for the property were modified to support sale of a portion of the property and an elevated rail corridor and its supporting berm were no longer necessary. Nonetheless, the studies and analyses that had been completed provide useful guidance for development of similar sites in the future. These two case histories are illustrative of the types of geotechnical issues and problems that must be dealt with in remediation of contaminated sites and site development. Regulatory, legal, social, political, and economic considerations are often of equal or greater importance in reaching acceptable solutions than are the scientific and technical aspects of the project.
Department(s)
Civil, Architectural and Environmental Engineering
Meeting Name
5th Conference of the International Conference on Case Histories in Geotechnical Engineering
Publisher
University of Missouri--Rolla
Document Version
Final Version
Rights
© 2004 University of Missouri--Rolla, All rights reserved.
Creative Commons Licensing
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Document Type
Article - Conference proceedings
File Type
text
Language
English
Recommended Citation
Mitchell, James K. and Mitchell, Richard A., "Environmental Geotechnics: Two Case Histories" (2004). International Conference on Case Histories in Geotechnical Engineering. 7.
https://scholarsmine.mst.edu/icchge/5icchge/session00f/7
Environmental Geotechnics: Two Case Histories
New York, New York
About 20 million gallons of liquid hazardous and toxic industrial wastes were disposed at the Hardage Site, about 35 miles southsouthwest of Oklahoma City, from 1972 to 1980. Following Superfund designation of this site by the EPA, identification of a few hundred companies as Potentially Responsible Parties, and a court ordered excavate, incinerate, and re-entomb remedy for its remediation, many of the companies joined to form the Hardage Site Remedy Corporation (HSRC) for implementation of design, construction, operation, and maintenance of the facility. With the aid of a panel comprised of experts in the disciplines relevant to contaminated site remediation, an alternative remedy was developed and shown to be both more protective of the environment and more cost effective than the EPA remedy. The HSC was successful in its lawsuit for adoption of its plan. The key geotechnical components of the remediation included (1) demonstrating that the clay-shale formation underlying the site was intact and not susceptible to adverse interactions with the liquid wastes, thereby justifying the use of this formation as a bottom barrier; (2) determining the hydraulic properties of the soil formations above the bottom barrier and analysis of the NAPL and soluble contaminant transport, (3) the construction of a 2700 ft long, 67 ft deep (on average), and 3 ft wide gravel-filled trench, keyed into the bottom barrier, that serves to intercept wastes that migrate and diffuse from the buried waste liquid sources, and which would otherwise flow offsite, and (4) the design and construction of a low permeability composite cap over the disposal area. In the second project described in this paper, plans for the redevelopment of a large rail yard area in Sacramento, CA were significantly impacted by the presence of a variety of soil contaminants in potentially liquefiable sandy soils. A portion of the approved remedy for this site included consolidation of contaminated soil in a fully lined and capped containment structure (know as the “rail berm”, or simply the “berm”) that would ultimately be used to provide secondary flood protection and would be used to elevate up to seven sets of rail tracks above grade. This project was significant in that it essentially represented construction of a waste containment facility in the middle of a major metropolitan area. As a result, both environmental and seismic safety issues had significant impacts on design and considerable subsurface investigation, laboratory testing, and engineering analyses were completed to address these issues. Perhaps the most noteworthy geotechnical issue for this project was subsurface soils along the alignment of the planned containment berm that were subject to liquefaction. One of the key aspects towards securing approval of this project was frequent communication with a number of regulatory organizations and project team members (both informally and through regular project meetings) to discuss the rationale for project concepts, planned investigatory procedures, the results of field and laboratory studies, and the results and implications of the design analyses. Through this process, early regulatory agency “buy-off” on project concept minimized the delays that frequently plague environmental projects. Notwithstanding the significant costs associated with a planning, analysis, and design process that addressed redevelopment of a 240 acre former industrial area and despite securing preliminary regulatory approval for construction of the containment structure, the project sponsor opted to terminate the project in favor of contaminated soil excavation and off-site disposal. The principal reasons for the change were not costs, geotechnical issues, or regulatory or public acceptance. Rather, land use plans for the property were modified to support sale of a portion of the property and an elevated rail corridor and its supporting berm were no longer necessary. Nonetheless, the studies and analyses that had been completed provide useful guidance for development of similar sites in the future. These two case histories are illustrative of the types of geotechnical issues and problems that must be dealt with in remediation of contaminated sites and site development. Regulatory, legal, social, political, and economic considerations are often of equal or greater importance in reaching acceptable solutions than are the scientific and technical aspects of the project.
