Geological and Geotechnical Engineering in the New Millennium: Opportunities for Research and Technological Innovation (2006)

Can you imagine a world where none of its billions of people lack potable water? Imagine a world where the energy needs of its ever-growing population are met without releasing huge amounts of carbon dioxide into the atmosphere and without other deleterious impacts on the environment. Imagine a world where infrastructure development keeps pace with population growth and urbanization, providing secure, affordable, and reliable shelter, transportation systems, waste management, water supply, and energy distribution for all its inhabitants. Imagine a world where foundations and tunnel linings are built using microorganisms to strengthen and stiffen the foundation soil. Imagine a world where advanced warning of impending natural hazards allows for sufficient time to prevent loss of life and to mitigate direct and indirect economic and social impacts. Imagine a world where toxic and other harmful discharges to the environment have ceased and where all past environmental impacts have been remediated. It may be hard to imagine such a world because it is so different from the world we live in, but with adequate investment in geoengineering research and development at least some, if not most, of this may be within our grasp. The purpose of this report is to examine strategies for such investment. The context for these strategies can be examined by looking at selected vignettes that illustrate where we have come from, where we are, and where we must go as geoengineers.

On the evening of October 9, 1963, after a period of heavy rain, a block of rock of some 270 million m³ detached from the mountainside above the reservoir impounded by the Vajont Dam in the Italian Alps (see Figure 1.1). The rock mass reached an estimated velocity of 110 km/hr by the time it reached the reservoir. The wave of water displaced by the landslide destroyed the town of Casso, 260 m above the reservoir on the opposite side of the valley, and then sent a wave of water 250 m high over the top of one of the world’s tallest dams and crested at 262 m. In Longarone and other hamlets downstream 2,500 unsuspecting villagers lost their lives that evening. The dam remained intact.

The geology of the reservoir area was incompletely understood and mapped. The analysis conducted after the disaster found that the massive slide occurred along an unrecognized clay layer in the limestone bedrock. The lack of knowledge of the geology and a misunderstanding of the

FIGURE 1.1 The Vajont landslide looking from upstream (image courtesy of Professor E. Bromhead, Kingston University; used with permission).

geomechanical behavior of the rock mass led to a reservoir management policy that ultimately resulted in disaster. Pore pressures built up along the clay seam and reduced the normal strength and shear modulus of the rock mass, resulting in a catastrophic brittle failure (Petley, 1996).

Forty years ago large dams were among the most complex structures that geoengineers dealt with, but our understanding of the interaction between such large structures, the reservoirs they impound, and the rock masses on which they were built was limited. There were sizeable gaps in our understanding of geomechanics, our ability to map the subsurface, and our ability to provide adequately for human safety. The studies that followed the Vajont Dam failure improved our understanding of the geomechanical behavior of rock masses.

The Central Artery/Tunnel Project in Boston, Massachusetts, (the “Big Dig”) is one of the most complex and costly public infrastructure projects undertaken in the United States (NRC, 2003a). More than one third of the project is underground, a condition that may foretell an important trend in urban infrastructure development in this century. The project had many noteworthy technological accomplishments in geotechnical engineering. The deep slurry walls constructed in soft clay were the largest use of such a construction technique in North America. These walls facilitated successful completion of deep excavations adjacent to fragile historic structures with few adverse effects. The soil freezing and tunnel jacking at Fort Point Channel allowed a tunnel to be constructed under active railroad tracks with no disruption in service. An underpinning technique allowed a tunnel to be constructed under the Red Line subway without settlement or disruption in service of the public transportation network.

Perhaps the most important aspect of this project was that it managed the relocation of complex urban infrastructure from surface to underground while minimizing the impact on the population living in the vicinity and the disruption in service to those using the existing

infrastructure. One major reason for the successful mitigation effort was the improved ability to predict, measure, and control ground movement during construction projects. One informal estimate put the savings due to the effective instrumentation at many million dollars (Personal communication from W. Allen Marr to John Christian, March 2003). The improved understanding of the geotechnical behavior of soil and rock masses, new tools and technologies that aid characterization of the subsurface, and improved ability to match construction technology to geotechnical behavior has given city planners new options for relocation of urban infrastructure. The Central Artery/Tunnel Project team worked closely with the affected populations to mitigate the noise, dust, utility, and transportation disruptions associated with construction. The incorporation of the social aspects of the construction design and execution begins to follow some principles of sustainable development (see for example http://www.nae.edu/nae/naehome.nsf/weblinks/NAEW-4NHMAT?opendocument/).

While the project was successfully completed by most measures of success, the record was not perfect. The project was originally estimated to cost $2.6 billion in 1982 dollars; it is now projected to cost $14.6 billion (2002 dollars) (NRC, 2003a) after completion in 2005. In addition to an increase in the scope of the project, a significant portion of the overrun was caused by three factors: (1) inadequate mitigation and community involvement in plans for crossing the Charles River, leading to litigation and delay; (2) unforeseen geotechnical complications in crossing the Fort Point Channel; and (3) inflation. In addition to the initial cost overrun, breaches in the panels and leaks in the overhead connections have developed and are currently subjects of intense study and ongoing repair efforts. Thus, although the project dealt effectively with many complex issues, community mitigation and geoengineering issues combined to create major delays and cost overruns. One of the lessons of the Big Dig is that the cost of underground relocation of infrastructure is still high and must be reduced. Reducing the cost of critical infrastructure improvements in the inner city environment will require research and innovation.

New technologies and tools will change the way geoengineering is done in the future (see Chapter 3). The coupled interaction between the biological and mineralogical components of Earth materials must be explored to understand fully the behavior of a rock or soil mass and the consequences for large- and small-scale phenomena. New engineering approaches will be accommodated by “smart” materials that sense and communicate the status of their structural or chemical integrity, the use of biogeomembranes that are composed of microorganisms, and the use of biological organisms to stabilize and improve the ground and remediate the soil and groundwater. New structures can be engineered in and on Earth that minimize pollution and disruption to the environment or self-heal because they incorporate biological processes as part of the structure.

There are many situations where geoengineers can benefit from real-time, ubiquitous data in order to understand and manage Earth processes. This need will be addressed by new monitoring network schemes under, on, and above the Earth’s surface that provide feedback on the response of the rock or soil mass to human and natural forces. The ability to see into Earth with high resolution, at low cost, with minimum disruption, and with results in real time requires new types of sensors at the microscale, new deployment strategies of sensors to monitor pore spaces and rock fractures from within the soil or rock mass rather than from surface or boreholes, and the ability for small, distributed sensors to communicate with each other and to a central computer.

The large data streams made possible by improved sensing capabilities will require new approaches to management of data, database structures, computer models for understanding and prediction of geomechanical behavior, and multispatial, temporal modeling, and visualization of the geosystem.

Sustainable development of the built environment and natural resources is a new societal imperative for the twenty-first century (NRC, 1999; Sidebar 1.1). Sustainable development will require a new understanding and management of the behavior of Earth materials from the

nanoscale to the macro- and even global scale and the linking of engineering management of Earth processes with economic and environmental goals. An expansion of the traditional role for geoengineers will be Geoengineering for Earth Systems (GES) (see Chapter 4), which will include efforts to integrate social, environmental, and scientific issues into engineering solutions for Earth systems problems. This expanded scope will require new types and quantities of data, benchmarking, and new efforts in modeling. Some of the critical problems addressed by GES will include dealing with the legacy and future of energy use; developing geotechnology that is environmentally responsible and economically beneficial, especially for the developing world; holistic infrastructure solutions for urban environments; and perhaps most importantly, managing the emerging critical issues of global change.

No amount of smart new devices will replace engineering geological characterization and synthesis, in the broadest sense, which comes largely with experience. As well, a major challenge for the future is that engineers will need to be able to understand and implement highly technical solutions in concert with meeting the needs of economical constraints and societal concerns.

This future for geoengineering can be realized by a workforce that is broadly educated, able to adapt to emerging problems and technologies, and representative of all segments of society. This workforce should be educated in a university system that facilitates and rewards interdisciplinary education and research (see Chapter 5).

This committee uses the term “geoengineering” to be inclusive of all types of engineering that deal with Earth materials such as geotechnical engineering, geological engineering, hydrological engineering, as well as Earth-related parts of petroleum engineering and mining engineering.

Many different types of problems and projects, ranging from the microscale to the global scale, draw on the geosciences and geotechnology for their solution and effective implementation. This report focuses on

the technology and science that must be known to enable problem identification and solving, robust and cost-effective designs, efficient and safe construction, assurance of long-term serviceability, protection from natural hazards, and continuing respect for the environment and concern for societal interests. These tasks are the essence of modern geoengineering. Geoengineers try to answer questions such as the following:

• What are the soils and rocks, and where are the boundaries?

• Where is the groundwater and how is it moving?

• How do the soils and rocks respond to different stimuli (e.g., loading, unloading, exposure, flows of fluids, changes in temperature, disturbance)?

• Why do these materials respond this way?

• How can we beneficially control or modify the response of these materials?

• How do we relate the answers to the problem at hand?

In virtually every case of building on, in, or with Earth materials, geoengineers need to know about the following:

• Volume change properties;

• Stress deformation and strength properties;

• Fluid and gas conductivity through the soils and rocks;

• How will what we do change what we have; and

• Interactions that modify material properties. (Such interactions are particularly important for some problems, such as waste containment and storage, resource development and recovery, and environmental protection, restoration, and enhancement.)

The goal of geoengineering research and technology innovation in both the short and long term should be to provide the knowledge and understanding that will enable problem solving and projects to be done with more certainty, faster, cheaper, better, and with proper respect for sustainability and environmental protection.

This report explores ways to make geoengineering more expansive in both scope and approach. The problems of today and tomorrow will need to be solved with a wider variety of tools and scientific information than is currently employed, including Earth sciences, biological sciences, nanotechnology, information technology, and microelectromechanical systems (MEMS). The problems geoengineers solve are part of complex human, geologic, and biological systems. We need to recognize and address the systems context for geoengineering in order to construct appropriate solutions to problems that are affected by society, economics, geology, and biology. Perhaps most dramatically, we see a need for geoengineering in the emerging field of GES in our attempt to manage and sustain a habitable and beneficial environment on our Earth.

In order to motivate the changes we recommend in this report, the committee imagines a new future for geoengineering. Some of the ideas may be close to reality whereas others may turn out to be elusory, but they all present possibilities to strive for and potential goals for the future.

The Geotechnical and Geohazards Systems Program of the National Science Foundation (NSF) asked the National Research Council (NRC) to conduct a study to provide advice on future research directions and opportunities in geological and geotechnical engineering, concentrating on techniques for characterizing, stabilizing, and monitoring the subsurface. Initially the committee was asked to identify research priorities, potential interdisciplinary collaborations, and applications of technological advances to geological and geotechnical engineering. After the first meeting, the original statement of task was expanded, and the committee was asked to address the following:

1. Update the report Geotechnology: Its Impact on Economic Growth, the Environment, and National Security (NRC, 1989) by assessing major gaps in the current states of knowledge and practice in the field of geoengineering. Areas to be addressed should include,

but are not be limited to, research capabilities and needs, practice and fundamental problems facing it, culture, and workforce.

2. Provide a vision for the field of geoengineering.

   • What societal needs can geoengineering help meet? Examples include infrastructure, homeland security, urban sprawl, traffic congestion, and environmental degradation.

   • What new directions would improve geoengineering in ways that will better help meet these needs?

3. Explore ways for achieving this vision and recommend implementation strategies.

   • What new and emerging technologies are needed, including biotechnology, MEMS, nanotechnology, cyberinfrastructure, and others?

   • What workforce changes are needed?

   • What opportunities are there for interdisciplinary collaboration?

   • What barriers and constraints are there to achieving this vision?

The committee consisted of 12 members drawn from industry and academia (see Appendix A). Two members of the committee were also members of the NRC Geotechnical Board that authored Geotechnology: Its Impact on Economic Growth, the Environment, and National Security (NRC, 1989). The committee met five times to gather and evaluate information and to prepare its consensus report. The first two meetings were open meetings and were held in September 2003 in Washington, D.C., and in November 2003 in Irvine, California. The third meeting was a workshop held in February 2004 in Irvine, California. The committee met twice in closed session (March and April 2004 in Irvine, California) for discussion and development of the consensus report. The committee was briefed by and received written information from NSF representatives and experts from industry, nonprofit organizations,

academia, and state and federal government agencies (see Appendix B). Committee members also relied on information from published literature, technical reports (including previous NRC reports), and their own expertise.

In keeping with its charge, the committee did not review NSF program elements or other geotechnology research programs in the federal government. This report provides advice for NSF program managers, but it also contains advice for the geological and geotechnical engineering community as a whole, and for other interested parties, including Congress, federal and state agencies, industry, academia, and the general public.

The report recommends research directions, but as it is not a program review, it does not include specific budgetary recommendations. The report is organized as follows. Chapter 2 provides an update of the 1989 report on Geotechnology: Its Impacts on Economic Growth, the Environment, and National Security (NRC, 1989). The committee identifies the changes in societal issues that create new imperatives for geotechnology and discusses what has been done to address the research agenda outline in NRC (1989), what is new, what is different, and what still needs to be done. Chapter 3 develops the committee’s vision for geoengineering in more detail by examining the new tools, technologies, and scientific advances in other disciplines and what they mean for geoengineering research. Chapter 4 introduces a new direction for GES and provides some guidance on a possible new GES initiative. Chapter 5 presents institutional issues and suggests some implementation strategies for NSF, as well as educational and research institutions and industry. Chapter 6 summarizes the committee’s findings and recommendations.

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