Why the future lies beneath our feet

Our congested cities should be looking down rather than pushing into the sky with vertiginous high-rises or expanding outwards with endless suburban sprawls, says one passionate underground engineering specialist.

Dr John Endicott, AECOM Asia Fellow, advisor to the Hong Kong and Singaporean planning authorities argues that underground space is vastly underutilised, and is an area of enormous, and unrealised potential.

Boasting more than 40 years of experience covering over 100 major underground projects globally, he says there are many opportunities to excavate and explore underground to meet the seemingly insatiable demands of our ever-growing population.

Just scratching the surface

Planning decisions made a generation ago are struggling to cope with the demands of today’s increasingly dense cities. The aspirational quarter acre block in the leafy suburbs disconnected from public transport appears wasteful by today’s standards.

Once we get past the first few metres of foundations and utilities, there is almost unlimited, virgin, available space. But safe and effective excavation depends on the stability of the roof and the side walls. Solid, strong rock such as the igneous granite under Hong Kong or the Hawkesbury sandstone buried under Sydney streets provides excellent foundations. These rocks can support caverns with spans of 27 metres, and sometimes more depending on the condition of the rock.

Global advances

At over 91 metres long and nine stories high, the Gjøvik Olympic Hall in Norway claims the title of the world’s largest excavated occupied cavern. This underground hall was constructed within the local gneiss metamorphic rock with the addition of applied rock mechanics.

It has a capacity of over 5,000 and hosted ice hockey games for the 1994 Lillehammer Winter Olympics. It is now a multi-use arena hosting a variety of sports, conferences and exhibitions within a climate-controlled, centrally-located, safe environment.

In Asia, Hong Kong and Singapore have leveraged their underground space to preserve their limited and precious aboveground amenities and common space.

The island cities’ underground railway stations are linked to retail, entertainment and sporting facilities to provide streamlined interconnectivity, improving sustainability and slashing commuting times.

It is possible in both Hong Kong and Singapore to commute, work, shop, eat out and visit entertainment facilities entirely indoors and mostly underground. Temperature-controlled environments will become increasingly attractive with climate change and growing extremes in weather.

Creating the space

While many of us may think of underground spaces as being dark, damp and unsafe this is not the reality.  With effective planning, expert geotechnical analysis, modern ventilation and a creative approach to place-making, caverns can be safer and more pleasant environments than aboveground office towers or shopping malls, allowing our open space to be used for parks, playgrounds and the natural environment.

The unrealised potential of underground space has the power to create a new, 24/7, climate-controlled metropolis without expanding our footprint, increasing congestion or spiralling commuting times. Our future can include concert halls; major sporting facilities; efficient and interconnected shopping, transport and work networks that will grow our cities’ capabilities.

All we need to do is look down and start digging!