Geological and Geotechnical Engineering in the New Millennium Opportunities for Research and Technological Innovation (2006) / Chapter Skim
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2 Updating the 1989 Geotechnology Report: Where Do We Stand?
2 Updating the 1989 Geotechnology Report: Where Do We Stand?
Pages 27-82
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From page 27... ...
infrastructure development and rehabilitation; 3. construction efficiency and innovation; 4.
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are more realistic: EPA's EMS and hazardous waste concept developed. problems and permit new disposal facilities are slow, Introduce new waste containment Significant advances have been complex, costly, and and treatment technologies.
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Develop nondisruptive designs Trenchless technologies, minimally for repair and replacement of invasive ground improvement, infrastructure. directional drilling, advanced ground reinforcement technologies now available.
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predictions. estimates of nuclear ground shock and of effects on underground structure, through several new efforts involving joint teams of DOD and DOE experts.
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Mitigation of Natural Hazards Technology must be used to Promote better land use planning. National and regional hazard more effectively reduce losses, maps (liquefaction, flood, landslide)
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NOTE: DOD = Department of Defense; DOE = Department of Energy; EMS = Environmental Management Systems; EPA = Environmental Protection Agency; GPR = ground penetrating radar; InSAR = Interferometric Synthetic Aperture Radar; LIDAR = light detection and ranging; NASA = National Aeronautics and Space Administration; NEES = Network for Earthquake Engineering Simulation; NSF = National Science Foundation; USGS = U.S. Geological Survey.
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From page 33... ...
remediation and containment barriers · Long-term stewardship of waste landfills Critical Issues: Many challenging and contaminated sites sites still need to be remediated. · Consideration of wastes as "resources Additional technological development out of place" is still needed, including development · "Cradle to cradle" management of wastes of appropriate waste containment and · Strategies and technologies for remediation technology for developing alternatives to landfilling countries and technology for · Carbon sequestration reduction, reuse, and recycling of · Remediation of contaminated sediments waste materials.
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From page 34... ...
observational method) · Biofilms for corrosion protection Critical Issues: Wider use of · Long-term durability of geosynthetic life-cycle cost analyses, including materials incorporation of sustainable · Use of formal reliability and life-cycle development and other social values, cost analysis improved modeling of environmental · Quantification and reduction of impacts of infrastructure development, uncertainties rehabilitation of existing geofacilities, and enhanced durability of geoconstruction.
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From page 35... ...
More efficient · Many aspects of tunneling and means of underground construction underground construction methods, remains a critical need and improved including materials handling, directional methods for site characterization control, excavation, safety, ground remains one of the greatest needs in support geoengineering. · Trenchless technologies · More energy- and cost-efficient ground Critical Issues: More efficient and improvement, including biotechnologies economical and less disruptive · Easier handling and better improvement underground construction and ground of wet and weak soils improvement, minimizing environmental impacts of construction activities.
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From page 36... ...
biotechnologies · Land use planning and zoning to Critical Issues: Improved regional account for geohazards and their hazard monitoring, forecasting, potential consequences communication, and land use planning; · Appropriate technology to mitigate appropriate hazard mitigation major losses of life and property in the technology for developing countries. developing world 36
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· New habitats (very long term) Critical Issues: Exploration at the frontiers of the natural universe ultimately leading to new frontiers for natural resource recovery and human habitation.
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The transition from waste treatment and stabilization to waste containment and monitoring as the presumptive remedy for many contaminated sites is but one manifestation of this trend toward less burdensome remedies. Another manifestation of this trend is the increasing use of risk-based corrective action, as it not only provides relief from burdensome zero-discharge standards but also facilitates beneficial reuse of impacted brownfield sites.
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. Geoengineering has made substantial progress in waste management since 1989, but significant challenges remain.
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Development of new and enhanced methods for geoenvironmental site characterization has lagged behind the rapid rate of advance in waste containment and remediation technologies. There have been some incremental advances in site characterization (e.g., fiber optic cone sensors for cone penetrometers to assess the presence of organic constitu ents in soil and groundwater and geophysical tracking of contaminant plumes)
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From page 41... ...
Besides soil and groundwater remediation, critical issues in waste management and environmental protection include mitigation of other environmental "insults" from human activities on local, regional, and global scales, appropriate waste containment and remediation technology for developing countries, and reduction, reuse, and recycling of waste materials. For instance, remediation of contaminated sediments is an emerging issue in waste management and remediation.
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From page 42... ...
The development of safe and economical waste containment systems, including the development of appropriate technologies for developing countries, remains an important task for geoengineers, as do surface water and groundwater management. Geosynthetic erosion control materials have not only significantly reduced the amount of sediment transported from newly graded sites, they have also provided for more aesthetic and sustainable surface water management systems.
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From page 43... ...
Geosynthetic materials and ground improvement techniques are routinely applied on major infrastructure development projects. In many states mechanically stabilized earth walls have become the de facto standard for bridge abutments and retaining walls for earthfill, and soil nailing and ground anchors are used with increasing frequency to retain cut slopes.
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From page 44... ...
Advances in trenchless technologies since 1989 have provided new, cost-effective methods for rehabilitating aging sewer systems, river crossings for pipelines, and utility installations in dense urban corridors. Slip lining, both with resin-impregnated socks and high-density poly ethylene pipe, and pipe bursting, wherein an "inflatable" tool is inserted into an existing buried pipe and expanded to increase the diameter of the FIGURE 2.3 Installation of deep soil mixed walls.
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From page 45... ...
Improvements in site characterization technologies have been slow and mostly incremental. However, significant improvements have been made in the application of ground penetrating radar for identifying subsurface utilities and shallow obstructions above the water table, and in the use of airborne survey methods for evaluating site conditions (e.g., near-surface soil type, geomorphology, shallow groundwater bodies)
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This jacked tunnel box was 36 feet high, 79 feet wide, and 379 feet long, and weighed approximately 32,000 tons. Used with the permission of the Massachusetts Turnpike Authority.
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At the time this photo was taken, the westbound tunnel box had been completely jacked into place, while the eastbound tunnel box jacking operation was still in progress. Used with the permission of the Massachusetts Turnpike Authority.
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Stabilization of these weak, saturated soils to control the loss of ground into the face during installation of each jacked tunnel was critical to the success of the project, both to limit ground move ments in the track area above and to assist directional control of tunnel boxes as they were advanced into the ground. To address these concerns, an innovative ground freezing approach that provided a stable, essentially dry excavation face over the full height and width of the tunnel was implemented by the contractor.
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Total spending of $59.4 billion annually is well below the $94 billion needed annually to improve transportation infrastructure conditions nationally. While long-term federal transportation programs remain unauthorized since expiring on Sept.
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Wastewater D Aging wastewater management systems discharge billions of gallons of untreated sewage into U.S. surface waters each year.
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cities with brownfield sites awaiting cleanup and redevelopment. It is estimated that redevelopment of those sites would generate 576,373 new jobs and $1.9 billion annually for the economy.
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Important geoengineering issues for infrastructure systems include construction and reconstruction of urban centers to minimize use of resources and impact on the environment, improved modeling of environmental impacts of infrastructure development and improved 52
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Sustainable development and improved environmental impact modeling will require large regional databases and data models, development of adaptive management techniques (i.e., application of the observational method) , and associated developments in monitoring technologies.
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Among the most notable are its widespread use in design and construction of offshore structures and the development of load and resistance factor design methods for transportation projects, especially for design of pile foundations. Reliability methods are particularly powerful when combined with observational methods to facilitate rational updating of designs and construction procedures.
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The actions identified in the 1989 report to improve construction efficiency and stimulate innovation are just as important today as they were then. Improved site characterization methods and development of 55
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GEOLOGICAL AND GEOTECHNICAL ENGINEERING IN THE NEW MILLENNIUM SIDEBAR 2.3 Uncertainty in Geoengineering Uncertainty is an essential and unavoidable part of geoengineering, but when we say that something is uncertain, what do we mean? One answer is that an uncertain event or condition is one that occurs at random with little or no external control, much like the throw of a pair of dice.
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What the engineer wants is a 20 percent probability of liquefaction if the data are observed. The latter type of output requires a Bayesian approach, in which probabilities are updated on the basis of new information.
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Adaptive management of urban construction (e.g., using auto mated monitoring systems to facilitate application of the observational method) also offers the promise of significant savings in geotechnical construction.
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To provide incentives for geotechnical innovation, mechanisms are required that will allow geoengineers to benefit proportionally from the risks they take. Geoengineering issues related to construction efficiency and innovation include development of more efficient and economical underground construction techniques, minimizing environmental impacts of construction activities, and development of more efficient and less disruptive ground improvement techniques.
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The mid-corridor encompasses 10 miles of depressed FIGURE: Mid-corridor track construction (image courtesy of the Alameda Corridor Transportation Authority)
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The Alameda Corridor opened on time and on budget on April 15, 2002. FIGURE: Map of the Alameda Corridor (image courtesy of the Alameda Corridor Transportation Authority)
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. Perhaps the most significant contribution geoengineering can make to construction efficiency is through improved site characterization, as unanticipated site conditions still represent the most common and most significant cause of problems and disputes that occur during construction.
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Trenchless technologies for minimizing construction impacts in urban areas and biotechniques for ground improvement are areas where geoengineering can also make significant contributions to construction efficiency through innovation, minimizing the social and economic disruption associated with infrastructure construction, and rehabilitation in urban areas. 2.4 NATIONAL SECURITY The national defense-related imperatives identified in the 1989 report (e.g., hardening, hiding, and limiting access to facilities by placing them underground; detecting underground facilities, activities, and caches; and monitoring for underground and surface activities)
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One major change in national security priorities since the 1989 report has been the focus on homeland security. As this focus on homeland security evolves from response to prevention, geotechnical engineering and, in particular, underground construction can play an important role in reducing the vulnerability of critical infrastructure systems from attack.
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Thus, important to the increased use of underground space for securing civil facilities are improvements in excavation and support system technology, including geologic and geotechnical characterization and in situ ground stabilization and improvement; improved capabilities for detection of underground objects and obstructions; and a more comprehensive system of cataloging and archiving the locations of known underground conditions and facilities. Improved detection of underground obstructions and underground activities may also play an important role in enhancing homeland security.
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Demand for most natural resources has increased steadily with population growth, industrialization, and urbanization. Furthermore, resource recovery becomes more chal lenging as the readily accessible supplies of raw material are recovered.
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The reward for successful investigation generally means discovery of a new, economically viable resource deposit that has a tangible economic value, while failure during natural resource exploration generally results solely in a direct expended cost with no return rather than in both direct and indirect costs associated with loss of life or disruption of services. The biggest change in our perspectives on resource discovery and recovery since the 1989 report is the growing focus on sustainable development (see Sidebar 4.2)
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From page 68... ...
Geo thermal reservoirs can be characterized and managed using geoengineering. In addition to its role in developing new energy sources, geoengineering plays a critical role in efforts to minimize and mitigate the environmental effects of current energy production technologies, including fossil and nuclear energy production and energy resource extraction.
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From page 69... ...
Resumption of construction of nuclear power plants will mandate a solution to the problem of nuclear waste disposal, discussed elsewhere in this report. In addition to energy development, resource recovery concerns involving geoengineering include providing safe water supply, developing mineral resources, and improving the energy efficiency of both the development of urban infrastructure and the infrastructure itself.
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In addition to the "conventional" geomechanical issues associated with economic extraction of mineral resources, geoengineering is squarely in the middle of environmental issues related to mining that range from developing new methods of mining that do not cause pollution or visible changes to the landscape to remediation and closure issues. To the extent that these environmental issues affect the social license to mine, geoengineers must participate in a dialogue with the public and regulators about manage ment and mitigation of these impacts of resource recovery, including mine waste piles, subsidence, water pollution, large mine pits that may fill with toxic water, and tailings ponds (NRC, 2002b)
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2.6 MITIGATION OF NATURAL HAZARDS Much of the work of the geoengineering community is directed at characterizing, evaluating, mitigating the risks from, and recovering from 71
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Geotechnology has been effectively applied over the past 15 years for natural hazard reduction. An excellent example of such an application is the Hong Kong Slope Stability Warning System, wherein state-of-the-art geographic information system technology is integrated with automated data acquisition and geoengineering information of landslide triggering to issue a "landslide warning" and facilitate emergency response (see Sidebar 2.5)
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From page 73... ...
Heavy rainfall triggers, on the average, approximately 300 to 400 landslides each year in these areas. To mitigate the substantial risk to life and property these landslides create among the 7 million residents of Hong Kong, the Geotechnical Engineering Office of the Civil Engineering and Development Department of the Hong Kong Special Administrative Region government has employed state-of-the-art technology to develop a sophisticated geographic information system (GIS)
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Furthermore, there is an increasing susceptibility to natural hazards owing to increased urban growth. There is also a need for development of hazard assessments and mitigation measures for developing countries that are less complicated and more easily understood and applied than those used in the United States (e.g., the NEHRP methodology)
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. As with environmental protection and waste management, a major challenge for geoengineering is to develop appropriate methods for geohazard mitigation in the developing world.
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Furthermore, population growth and urban growth exacerbate the impact of these natural hazards. In summary, critical issues in geoengineering for natural hazard mitigation include improved hazard monitoring and forecasting, imple mentation of land use planning, and development of appropriate hazard mitigation technology for developing countries.
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Therefore, hazard mitigation, including ground improvement, hazard monitoring and warning systems, and facilitation of disaster response and recovery, will remain significant geoengineering activities. Remote sensing technologies and the development of regional databases and data models will play an increasingly important role in natural hazard mitigation in the future.
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. natural resource recovery and human habitation.
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These knowledge and technology gaps include: · Improved ability to "see into Earth." Faster, more rapid, more cost-effective, more accurate, and less invasive techniques for characterizing the subsurface is perhaps the most important need in geoengineering, irrespective of the specific problem to be solved. · Improved sensing and monitoring methods, including improved geophysical and remote sensing technology, more reliable and accurate instrumentation, enhanced data acquisition, processing, and storage and incorporation of the collected data into appro priate information systems.
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· Development of subsurface databases and data models, including geological and geotechnical data, information on the built environment (e.g., subsurface utility locations) , natural resource and environmental data, and monitoring data for natural hazards and environmental conditions.
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The United States and the world need geoengineers and need advances in their abilities to understand, manage and design in, on, and with Earth. Geoengineering is crucial to addressing essential national and global needs, including infrastructure development and sustainability, the availability and reliability of our civil structures, provision of homeland security, protection from natural hazards, and expanding our frontiers of knowledge.
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