Sam Sherwood-Hale spoke to Kurt Zeidler, Principal at GALL ZEIDLER Consultants about the drivers for innovation, sustainability in tunnelling and the untapped potential in underground spaces

At some point, every company will face the question of how to continue maximising earnings from their current business practices whilst also investing enough in innovation so they can turn a profit in the future. How can a company achieve the necessary creativity to innovate without compromising their existing business?

There are quite a few aspects to that. Often people don’t want to be the first, you can waste money and time moving forward with something that could be a good idea but then there’s a risk you may fail, with someone else picking up that idea and running with it, so they get the advantage of your initial work without any of the risk.

Innovation should always have an end goal that is providing an overall improvement – the question you have to ask is: does it help us improve safety, improve quality, improve life time of the structure, improve construction and operation cost or speed up progress and is it safe to use? These are the main drivers of innovation.  I have seen some innovations in ground treatment, with new, efficient materials being developed that turned out to be not sustainable because the material used for grouting had a negative environmental impact. These are the risks when it comes to
innovating, as there is no compensation for being forced to stop a new idea or finding out an idea may not work after significant investment.

Innovation doesn’t always need to be a revolution, we as a company have often come up with ideas that may not have been fundamentally new, but we have taken existing elements and assembled them in a novel manner to accelerate construction which helps the contactors’ margin on that job – so the reward for innovating in that context is a little more immediate.

Earth pressure balance tunnelling machines were a UK innovation, originally supported by London Transport to facilitate tunnelling in south-east London where the London Clay is absent. It was a significant risk as it may not have worked but the trial tunnel using this technology allowed the technology to be further developed and modified by other European companies to facilitate safe and efficient TBM tunnelling in soft ground. This has subsequently become the standard closed face tunnelling method in soft ground where there are appropriate ground conditions. This didn’t come about because of a desire to innovate out of nowhere, it was the demand of work in urban areas where soft ground is more common.

I was recently involved in a conversation regarding an upgrade scheme for a station on the London Underground, some of the suggestions were unusual but the objective was simple – build a new shaft next to an old escalator. The client didn’t say: ‘we need something new’ The instruction was to build this new shaft, and then the contractor wanted to optimise the use of materials and overall productivity.

You mentioned safety standards, there is always the demand there because you can always be safer. When it comes to sustainability, how can a company know that it has innovated some new way to be sustainable, or a twist on a technique that makes that practice more sustainable?

As an example, if we consider materials, we know that durability is key for concrete structures and you need to protect it from the attack by aggressive groundwater conditions, calcification and carbonisation, etc. To do this you can improve the durability of the concrete by controlling the crack width, additives to the concrete mix etc., or you can protect the structure with waterproofing. If you go back to Brunel’s Thames Tunnel, there was a demand for waterproofing because he had to keep the interior of the tunnel dry, so he developed a water diversion system to control ground
water infiltration and keep the tunnel dry. Water could still penetrate the structure, but it did not reach the interior of the tunnel. Today we have materials that shield the structure from the groundwater to enhance the durability of the material, extend the structures’ lifetime which in turn makes it more sustainable.

But there are also new requirements that hinder this drive towards sustainability. On one major project, it was a requirement for each and every contractor along the project to redo all the concrete testing for every piece and every type of concrete. They were using the same mixes but were forced to redo the testing – to go through pre-construction approval testing on such large projects requires thousands of cubic metres of concrete tested and then thrown away. So we have these requirements that can inadvertently increase waste when the standards are being strictly followed without anyone thinking how to follow the standards in a more efficient way.

We tried to stop this on another project. We were able to convince the Client to use concrete mixes that had been tested and approved on a different project before without going through the same
testing procedure again. It comes down to individuals to push things forward including representatives of clients who are empowered to make such decisions.

On another project which we were working on, a tunnel was planned to go through a protected groundwater area, we knew with the tunnel, we would build a barrier that would cut across the groundwater stream. The relevant environmental authority said we couldn’t build it, but we were able to develop a way to minimise the barrier action which didn’t clash with the environmental standards and get the approval. These may be small things in the overall world of tunnelling, but they add up.

Are we as smart as those early innovators, or are we too reliant on the new technology that wasn’t available one hundred or so years ago? Has innovative thought progressed at the same level as the available technology?

Now that we know more about materials, the thinking has changed. Things are tested more often, given the experiences we had with lead and asbestos, for example. There are more authorities watching over the development of technologies and identifying issues, whether they are hazardous, or if they have an environmental impact. It is often leniency or comfort with known technologies that hampers innovation, or unwillingness to take some risk, albeit it may be a small risk. The technology is often available, the thought is there, but it requires the right people to make logical decisions – on all sides – clients, designers and contractors.

I know of one project where the contractual requirement was to purchase a brand new tunnel boring machine (TBM) for a 150-metre long tunnel, a complete waste! It is a simple concept to use new equipment. I understand the client’s desire for delivery certainty. A used, refurbished machine would have worked perfectly fine and was available from another completed job nearby. No long lead time, no major transport or new equipment would have been required – and the risk for project delays due to machine problems would have been minimal. This is something that is an issue, not only with materials and equipment, but also with space. It is not always about building new structures or innovation. Sometimes underground space is available, old tunnels are often very well built and can be adapted and reused, it might just require repair of the lining or re-lining or refitting. Sometimes re-using existing structures may be innovation.

You may have an existing ventilation tunnel available that can be used for other things, if we need new transport infrastructure in existing urban environments. Why can’t we use existing tunnels? In Chicago, they used to have an extensive tunnel network for freight transport, which was built and used early last century. Unfortunately this network has been abandoned, and some new underground structures now cut across them, so they can’t be reused – but that could have been avoided if the possibility of reusing the tunnels had been considered in modern urban planning.

In today’s congested urban environments, the use of existing tunnels for underground transport has a large potential for congestion relief. This is not the only example of a city where the reuse of existing underground infrastructure could yield significant improvements.

Who can drive these improvements?
In my opinion, the biggest driver for innovation is the demand; for example, the increased demand for urban underground infrastructure involved the construction of more and larger underground structures in more challenging ground, in busy areas with ever developing technologies.

There is less room for infrastructure at the surface, hence more demand for underground schemes. This demand can be initiated by clients who want to build the infrastructure and by contractors who want to meet programmes, win jobs, make profit. Clients can indirectly drive innovation by tendering more challenging projects, but at the same time, clients have to follow strict procedures which is not necessarily cultivating innovation.

Consultants often have innovative ideas but need partners to realise new approaches whereas contractors have the drive for innovations for various reasons: Competition, cost efficiency, efficiency of use of personnel, material and equipment.

How about inventors, there are not many people who decide to invent something new for the sake of invention – they see the need for something; also, there are not many people who have the financial ability to invent and test costly new methods.

Improvements in the past resulted in more reliability, safety and efficiency, hence an increase in production. There was, however, no ‘quantum leap’ in speed and efficiency. It needs thinking outside the usual models, often well-known methodologies can improve the speed and efficiency significantly, if they are used in a novel way.

For that big step, it needs the innovatively thinking engineers (both inside and outside the tunnelling industry), clients and contractors to collaborate. It does not need PR stunts, it needs serious work.