The Thames Tunnel under the River Thames in London was built in 1843. It was the first subsea tunnel and is still in operation today! The construction method used was the so-called Shield Method (by I.K Brunel), with a frame to support the excavation as the tunnel face moved onwards while the excavation progressed. The Shield Method was invented to improve workers' safety and to increase production rates. This method was used for most of the UK's long railway tunnels during the Victorian era and paved the way for the modern Tunnel Boring Machines (TBMs)
When people connect, ideas evolve; knowledge is shared; markets thrive; technologies develop; opportunities for people grow; and consequently, the economy improves. A growing urban economy needs more energy, more water, more food, and a better supply of products. Developed economies very often support investments in innovation and improvements to the environment when constructing major infrastructure projects. Road infrastructure, public mass transportation systems, water supply, sewage, power plants and powerlines etc. are needed in both developing and developed economies. And tunnels often provide the solution to how these 'needs' can be met, with respect to the planet and to future generations.
In order to reduce the demand for natural resources, existing infrastructures must serve their function for longer before new infrastructure is constructed.
We're going to focus more on transportation tunnels for the purposes of this article…
The first underground metros were constructed in major cities such as London, Paris, Budapest, and New York over 150 years ago and are still in use today. The use of underground tunnels is a particularly effective mode of transportation with expanding underground travel network systems around the world. They do not influence or block existing activities on the surface and are particularly attractive where there is a growing demand for space in cities due to the fast pace of urbanisation and land scarcity. Also, the traffic in the tunnel is not affected by congestion within the surface traffic systems.
And it's not just in cities that tunnels are considered for transportation purposes - rural areas have a growing demand to preserve the natural environment. With a high demand for transportation of people and goods (usually requiring longer roads and longer rail lines), sometimes passing difficult obstacles like mountains and bodies of water, it is often a requirement that infrastructure takes up less surface space, both in urban and in a rural setting. And let's not forget that it is often preferable for infrastructure to be 'invisible'…
Societies invest in infrastructure for the common good. Infrastructure should not only support the economy in the region, but also protect social groups, the environment and the climate. Simultaneously!
For major infrastructure projects, there is often a balance to strike between the planned construction cost and the identified benefits (or drawbacks). Other solutions constructed at ground level, such as a bridge, could often serve the same function and are typically less costly. However, tunnels are often selected for the long-term benefit of freeing up space at the surface.
When planning new infrastructure, solutions where the most benefits are identified at the lowest possible cost, MUST be considered. However, the solution with the lowest cost is not always the solution with the most benefits. Therefore, logical and systematic decision making is required to identify a sustainable solution with an acceptable balance of pros and cons. The detailed solutions will differ depending on several factors - the location, for instance.
Subsea tunnels are constructed as fixed links across rivers, inlets, straits, fjords and harbours, where tunnels are sometimes an excellent alternative to a bridge. For example, in a harbour where a tunnel could have less impact on shipping traffic. Or where a tall bridge could require long approach spans or influence the flight paths to and from a nearby airport. In general, where there is an opportunity to protect the existing natural landscape, or maintain the identity of a place, a tunnel may be an excellent alternative to a bridge.
Desert-like major cities exist around the Mediterranean Sea, in the Middle-East, the South-West of the US, Mexico, in some regions of India, China and in the Andes mountain South America. Without tunnels, people living in these areas would only have access to water by open canals with needs for protection!
Dynamite (based on nitroglycerin) was developed and commercialised by Swedish chemist Alfred Nobel in the 1860s, after his studies in Paris. Until then drill & blast tunnels were constructed using different types of gunpowder.
Major Tunnels Market Director / Head of Sustainability Transportation International
Tunnels and Underground Infrastructure, Denmark