Those of us in the underground industry recognise the many benefits of building infrastructure underground. These benefits include less disruption during construction and significantly reduced environmental impact. Moving major portions of transportation infrastructure underground can preserve the urban historical heritage and restore public space for better use.
So what keeps us from putting more facilities underground and taking advantage of these benefits? One barrier is that we still don’t seem to be able to accurately predict the final cost and construction duration for our major projects. Although tunnel projects can be the lowest cost alternative in many instances, especially when considering social costs of disruption to neighborhoods and other real but soft costs, the final cost and completion time for underground work has historically been very unpredictable when compared to aboveground construction. There have been numerous well-publicised cost overruns on underground projects, for which many reasons and or excuses have been provided. These include the insufficiency of pre-tender subsurface investigations; design solutions that are not constructable; unfair and one-sided contract terms and conditions; procurement methods that carry high contractual risk, permitting inefficiencies, mismanagement by either or both of the contracting parties; and a lack of mutual respect that can arise from not understanding the other parties’ motivations.
Another barrier is the advancement of alternative technologies. In the wastewater industry, the standard "convey and pump" solution to CSOs is being replaced in some areas by a green infrastructure solution. Such facilities allow storm water runoff to infiltrate the ground instead of being captured by storm drain systems and diverted to underground conveyance systems. Although not usually as effective a solution in terms of CSO reduction, such green solutions can be orders-of-magnitude less expensive. Although the long-term reliability of these solutions has yet to be evaluated, the lower capital cost is an extremely attractive feature. Alternative technologies are also emerging in the field of power generation. Some of these technologies can threaten the development of major hydropower developments, many of which rely on penstock and tailrace tunnels and in some cases underground powerhouses. However, other technologies, such as offshore wind and geothermal, actually present opportunities for underground construction.
Another obstacle to our industry is the fact that most underground projects take a long time to develop. The time needed for planning, alternative analysis, subsurface investigation, design, procurement, construction, and commissioning can easily run from 10 to 20 years. The funding for publicly owned projects of such long duration can be uncertain, especially when they are subject to political pressures, as is typically the case for high visibility publicly funded projects. Political stability is a necessary component to completing a controversial public underground project.
As an industry, we can do better. In fact we must do better if our industry is to grow and develop to serve the needs of society. It is vital that we improve our project performance, particularly in the prediction of the time and money necessary to complete the work. We, that is all of the project participants (owners, contractors, engineers, and suppliers), can do this by learning from our past successes and failures. Some of this lessons-learned analysis can be done through the sharing of positive and negative case studies, in the forms of articles, conferences, and other educational media. This exchange of information is currently much less effective than it could be. This is in part because few project participants are willing to share what went wrong, despite the well-known fact that we learn much more from our failures than we ever do from our successes. Risk management is another area needing improvement. In addressing cost and schedule risk, the industry should develop a more robust risk analysis than is currently available, with the objective of quantifying the uncertainties. Simply maintaining the current qualitative approach to risk management will not resolve our inability to get the cost and schedule predictions right.
Equally important, we need to develop further advances in underground technology. Material suppliers and equipment manufacturers have been at the forefront of technological advances in the underground industry. While not discouraging this innovation, we must engage other stakeholders and inspire them to generate more innovative ideas. Much of this innovation can be done by academia, through graduate research programs, provided sufficient feedback is available as to what research is needed. Most of today’s underground projects are instrumented with volumes of data, from both mining equipment and geotechnical instrumentation. But onsite project staff typically have neither the time nor the motivation to analyze these large volumes of data for future use. Overcoming contractual barriers to data ownership so that this information can be made available to academia for research would be a giant step in furthering technological advancement. Such advances in technology will make tunneling more efficient, and thus less expensive.
Because a large portion of the underground business is for public owners, industry representatives, including owners, contractors, engineers, and suppliers can and should become active in the political process. This can be done by providing factual information to political decision makers, particularly on how underground solutions can help solve public problems — in transportation, water and wastewater, and other societal uses. Our underground societies and associations, as well as the International Tunneling and Underground Space Association (ITA) can all play a role in this. Another avenue is the active collaboration with industry groups in the areas of urban planning and design. Many of the benefits of underground construction match up well with the goals of urban planners — e.g., less sprawl and more green space. Becoming involved is critical to the long-term health of our industry.
If the industry successfully addresses even some of these barriers, the demand will outstrip the supply of engineers and contractors to service it. To be ready for this, we must reboot our basic educational programs across the board, including secondary school systems, undergraduate, and graduate institutions. And practitioners — including owners, contractors, engineers, and suppliers — must not forget that a significant part of a tunneller’s education has been and will always be on-the-job training. I would welcome an industry dialogue with a view to developing a worldwide strategy for how each of these education systems can best contribute to the efficacy of our industry.
The underground industry faces a number of barriers, but if all of the stakeholders in our industry participate in advancing the state of the practice, the underground construction industry can become one of the most efficient sectors of the world economy.
