• Smart underground structures and conduits that report their status;
• Health and safety considerations, such as cost-effective ventilation, light, and concerns related to radon exposure or fire control;
• Lifecycle cost and benefit issues, including reduced energy needs for heating and cooling, reduced construction material use, use of excavated materials, increased longevity of underground structures and reduced maintenance associated with stable temperatures and isolation from surface weathering effects;
• The potential sustainability benefits of increased use of underground space for human transportation systems, including roadways and mass transit, and freight;
• The potential for integrating of energy, water, and waste systems for certain urban regions to improve sustainability; and
• How underground development might address concerns related to the impacts of climate change on the urban environment.
The committee will recommend directions for a new underground engineering research track focused on earth systems engineering and management to ensure future human resources for sustainable underground development, will analyze the advantages and disadvantages of establishing a new research center in this area, and consider other potential options for enhancing the human resource capacity for sustainable underground development (including the status quo). The committee also will consider from a social science point of view, the policy, economic, and human behavioral drivers that promote or inhibit the development of the subsurface in a sustainable manner, but will not make policy or funding recommendations.
THE UNDERGROUND FOR SUSTAINABILITY
Sustainability is defined in this report as the ability to meet present societal needs without compromising the ability of future generations to do the same. Maintaining or improving quality of life and maintaining long-term ecological balance are among societal needs. An unhealthful natural environment can negatively impact food, water, and air supplies and degrade quality of life and health to unacceptable levels. Resilience, an important aspect of sustainability, is defined as the ability to respond to environmental changes—especially natural or human-caused adverse events—with minimum impact on functioning.
Master plans of some cities (e.g., Singapore) include extensive underground use. Well-planned underground infrastructure can positively influence land use and development decisions and can reduce vehicle use and associated impacts. High-density urban centers may depend on centralized services but can capitalize on centralization to increase sustainability. Underground transportation infrastructure (e.g., urban roads and highways, public transit subways, grade-separated and underground freight railroads, high speed rail, and pedestrian rights of way) can address multiple growth-related challenges in urban areas