Digital simulators in underground construction are a relatively new segment of the training portfolio. Today operators can learn new skills, and test existing competencies on a range of tools from simulators for shotcrete and injection application to those that simulate segment erection and even full TBM operation.
Historically these skills have been gained through experience, but times are changing as contractors realise that the use of simulators can save money and improve safety. Clients too are aware of the benefits. In Sweden for example the Swedish Transport Administration (Trafikverket) mandated project certification for all sprayed concrete operatives involving both theory and practical training on its E4 bypass project.
A move that Swedish mining and tunnelling training and education company Edvirt was ready for. The firm itself was founded following a prototype simulator research project at the Chalmers University of Technology in Sweden. “We offer three courses as a basis for certification on Stockholm. Practical shotcrete training with simulator, the shotcrete theory course and then an injection course,” explains Andreas Höglind, 3D designer at Edvirt. The shotcrete courses take four and a hafl to five days and the injection grouting course two and a half to three days. “Those with experience may not need so much time but experience is not always the same as skill, especially with shotcrete. Many of the operators we have worked with are experienced but they are not skilled because they have been doing something for 30 years but never been evaluated on it,” adds Höglind.
This is something that José Habeeb Diaz knows extremely well. An experienced nozzleman and training expert, José works for Germany’s Putzmeister both delivering training using the new Edvirt simulator, and commissioning Putzmeister equipment. “You can’t imagine the number of people who are experienced in spraying concrete but don’t do it in the correct manner,” he says. “Application of shotcrete is very important because it has to be done at a certain angle and certain distance. People get into working habits and don’t realise it. Sometimes they have been doing it for years in the wrong way,” says Diaz.
However, using a simulator tells the operative and the trainer the amount of concrete that stays on the surface and how much goes on the floor. “You can see the waste,” says Diaz, who demonstrates the effectiveness of the simulator by allowing experienced operators to undertake simulator application at the start of the training. After training the much-improved performance can once again be evaluated.
“You can directly see it make a difference,” says Henrick Eriksson, another trainer and shotcrete expert who works for Switzerland’s Implenia and uses the Edvirt simulator for training. “Often operators use high speed on the pump because management want to be done as quickly as possible but they don’t understand that if you take a few minutes more you earn much more money in the efficiency of the material.”
To reach the required quality with a poor or average operator requires a lot more concrete, explains Eriksson, so their expertise usually depends on their experience and longevity in the business. “With simulators you can train beginners that haven’t done this before so you can improve both cost efficiency and security – you are more insecure if you have to train operatives with all else that is happening in the tunnel,” explains Eriksson.
This is an important point as previous practical training introduced risks on the jobsite. “If people on the jobsite make a mistake it could injure me so the simulator stops me from getting injured or injuring someone else. That is one of my main interests – safety. It can make things a lot safer,” says Diaz. Along with the compact nature of the equipment, which can fit into a suitcase as it requires only a laptop, a screen interface and the remote control, the benefits are clear. “This is easy to sell because if you isolate the sprayed concrete work, then 70 per cent is the cost of materials so how skilled you are is directly proportionate to the spend,” says Eriksson. With the simulator wasted concrete from rebounding for example is only theoretical. Good application is just one of the aspects covered in the training which also considers start up, cleaning and shut down.
“I make sure everything is included, not just spraying because understanding the process is important and the cleaning process is very important,” says Diaz. For example clogging in the line is an issue that can happen quite often if the concrete pumps are not properly lubricated before use or cleaned out afterwards. DRILLING SIMULATORS
Drilling and equipment manufacture Atlas Copco also has an extensive range of simulators and agrees that safety is one of the biggest benefits. “Simulator training can provide a safe environment for operators to practice and develop their skills,” says Mike Cassidy, product manager for training, global at Atlas Copco, who also points to cost and sustainability benefits. “Simulator training is the most cost effective method to train operators eliminating the cost for fuel. No fuel consumption also means no emissions and is better for the environment. “
Atlas Copco also says that the cost of using a training simulator is paid back in terms of operator productivity after just one week. Cassidy also points out that using a simulator means no loss in production as like the shotcrete training it no longer uses the production equipment on site. “Aside from the safety reasons to use simulators for operator training there are also several machine operation benefits. A well-trained operator will be able to operate the equipment efficiently reducing pre-mature failures and unscheduled maintenance caused by poor operation of the equipment,” says Cassidy.
Atlas Copco’s mining and construction business took the decision to make training technology a key part of its business back in 2011. “Not only do we want to be the market leader in equipment and service but also in training,” says Cassidy. The firm has a wide range of simulators from desktop, classroom trainer and cabin-based options, with or without motion platforms and conversion panel kits that allow these to be applied to boomers, loaders, mine trucks and spray concrete equipment.
Its most recent launch is the Boomer S2, which like its other simulators is built from the engineering plans of actual machines. To create a realistic field of view, the Boomer S2 uses the same cab as with the real equipment. Inside the cab, there is a multiple LED screen system, displaying real-time simulation. In addition, a large screen is mounted outside the cab, enabling a small group of operators to watch and learn. The simulators include full documentation regarding manuals and quick start-up guides; they can also be remotely updated and fault diagnostics can be monitored over the internet. A range of scenarios can be modelled including advanced drilling (6×6), advanced drilling (10×10), basic drilling, bolting, cross cut drilling, extension drilling, laser navigation, mine navigation, positioning, freemode, setup and positioning, surface tramming and underground tramming.
Looking ahead Cassidy says that the firm is continuing to update its training offerings. “To keep our edge on training, it’s important that we continuously review our current fleet and upgrade our hardware and software. We are also very active working with our capital equipment divisions investing and developing new simulators to support new equipment being introduced in the market such as the new Boomer S2,” he says. “Along with developing new simulators and new training scenarios for our existing simulator fleet, new technology such as virtual and artificial reality is becoming more popular and accepted in the market. This technology allows for even more interactive training and provides greater mobility and availability of our training portfolio.”
Fellow drilling equipment manufacturer Sandvik is working on development of a range of simulators in response to what it sees as growing demand in the market. “Most normal training takes place at the machine start up. Contractors have very tight schedules and cannot allocate enough time for training sessions. So, mostly they train their own staff by more experienced colleagues and take special attention at start up. Since drilling rigs tend to have more complicated, yet automatic, drilling control and instrumentation, the need for optimization or audit type extended training sessions is definitely growing,” says Jari Kymalainen, manager of lifetime support services at Sandvik.
He says that simulators have been more widely used by mining companies who have longer term investments and larger workforces. “I have to be honest saying that our own simulator offering has not been mobile or light enough to be optimal for shorter time or smaller projects. This must get changed and I honestly believe that this is what tunnelling contractors would need.”
To this end the firm is working on a suite of new simulators for its customers to support training on certain models of drilling rig, which it will start offering to customers towards the end of the year. “We will use this very controlled manner in the beginning by providing machine alike start ups and leave customers with a comprehensive learning environment with pre-set exercises and operator tests. This is not yet publicly available, but tests are going on with tunnelling and mining contractors.”
TBM SIMULATION
To date there has been less progress on the use of simulators for TBMs but this is changing. In early April French contractor Bouygues Travaux Public announced the launch of the first fully operational TBM simulator called THALIA. The simulator was developed internally over 18 months. Ahead of its launch the simulator was tested by experienced pilots before the first class of budding operators began their six-week training programme at the Gustave Eiffel Training Centre resulting in 10 newly-qualified TBM pilots.
The simulator has been designed to train and test responses for slurry machines and earth pressure balance machines in 15 scenarios. Bouygues TP executive vice president Bertrand Burtschell says that the machine is part of a wider move towards industrialisation and digitisation of the industry, which will eventually see TBMs operated above ground remotely. At the same time he forsees a growing demand with the Grand Paris Project alone requiring 170km of new tunnels to be created using TBMs. “As we want to continue working internationally we need to train up new teams so that we are capable in the future of operating five or six machines in Paris. It is a very big challenge,” explains Burtschell in the launch film (see link).
Steve Chorley, field services director at TBM manufacturer Robbins says formal TBM operator training is much needed. “Every operator in future needs to be licensed, you are licensed to operate a crane, licensed to operate a forklift, so why not be licensed to operate a TBM?” says Chorley, pointing out that this is particularly crucial for major cities where TBM operators are working beneath high profile, critical buildings and infrastructure.
“We need to be very careful. When people are new to the machines there is more possibility of problems happening so we start on the simulator, get familiar with the controls of the machine, then we can simulate the ground conditions,” he says. For these reasons Robbins is collaborating with the International Tunnelling Association (ITA) committee on education and training on a new 80-hour training course, and the Colorado School of Mines on a new simulator. The CSM simulator can model soft ground conditions and Robbins is contributing to this research.
The tool currently works on a PC but will ultimately be integrated into the TBM operators cab. So far this earth pressure balance machine simulator has modelled five scenarios: sand; clay; transitional geology; mixed face conditions and homogenous conditions.
It is planned to expand this in future to cover slurry and hard rock applications. “The biggest thing is that it trains operators on the functions of the machine before the machine even starts and it gives them a chance to experience what could happen if they do something that might not be correct,” says Chorley, explaining that it enables TBM operators to be taken through a multitude of scenarios – preventing the potential for future disaster. “It can tell the operator these are the ground conditions, this is what is going to happen, for example you have hit a boulder or you have pushed too hard and created heave, you have over excavated and created a sinkhole. That in major cities is very important,” he says pointing to a recent experience in Singapore where an operator rolled the machine 90 degrees.
“He left the screw gate closed, built up 4 bar pressure in the screw, and then when he realised he open the screw gate and the machine lurched forwards into the ground. The thrust cylinders lost contact with the segments and jammed the head into the face and created massive torque and rolled the shield. We recovered the machine in three hours and no one was hurt,” says Chorley, but had the driver encountered such a situation before or had a simulator to model his response, this would not have happened.
At the same time as collaborating on the simulator Robbins has redesigned the operator cab shifting towards what Chorley describes as the command chair. Development of this started 12 months ago. “I think the operator should be like a commander on the bridge of a ship. I want to get that cab as high as possible, and see the material on the conveyor behind the operator,” says Chorley, describing the chair as a helmsman arrangement with screens that come from each arm of the chair. First models are already scheduled to go to Nepal, India and Japan in late 2017. Another benefit of this set up is the reduced space requirement of the command chair compared to the operator’s cabin which can take up large areas underground. Future simulators will be placed in replicas of the command chair. “We are six months away from integrating the PC with the chair,” says Chorley.
Over in Malaysia MMC-Gamuda Tunnelling, a joint venture of MMC Corporation Berhad and Gamuda Berhad, is delivering the underground section of the Klang Valley Mass Rapid Transit Project (KVMRT). This involves construction of two twin bores, the first 7.8km and the second 12km. Using its experiences gained in tunnelling through the different geological conditions in Kuala Lumpur, the contractor has developed the ‘Variable Density (VD) TBM Operator Simulator’.
The training tool incorporates all different kinds of potential scenarios during excavation, such as dysfunction of slurry and grout pumps, blocky ground condition, high contact force between the cutter-head and the ground, pipeline blockages, burst pipes, worn cutter discs and blocked screw conveyor. “On this simulator, the trainees will be taught the functions of every button for the slurry circuit, the correct sequence of piloting the TBM in different type of ground conditions, the appropriate responses to be adopted when facing operational anomalies, interpretations of mining parameters trend and many more,” explains a management spokesperson for MMC-Gamuda. The simulator system is also equipped with the capacity to record the trainees’ profiles during any particular training session, eventually serving as an assessment tool to monitor the mining performance of trainees alongside their critical thinking skills when resolving potential technical problems.
“In the nutshell, the simulator replicates the actual TBM piloting configurations and operation, from the size of the real TBM operator cabin, its actual excavation cases, to the same buttons used,” says the spokesperson.
This is not the only simulator used by MMC-Gamuda. In December 2011 former Malaysian prime minister Tun Dr Mahathir Mohamed opened the project Tunnel Training Academy, designed to ensure that the tunnelling needs and expertise required for the project would be met, reducing the dependency for foreign expertise.
One of the tools used by the academy is a Herrenknecht erector simulator for training tunnellers on ring building. The tool is designed to help operatives make more precise positioning and can be set up to match the ground conditions and physical characteristics of the construction project. Around 500 staff have been trained using the simulator which the contractor says has made construction more productive.
“The use of this training simulator had a remarkably reduced learning time with an exponential learning curve. It had also improved the overall segment erection downtime, reducing the time consumed for ring production by half from one hour, which is the usual duration needed for a fresh tunnel crew to erect a full ring if they were not trained on simulator,” says the spokesperson.
Reasons for this are varied, says the contractor, but a key advantage is that it allows trainees to accomplish their work more confidently allowing countless trials and errors with no need to worry about equipment wear and tear.
“It provides a friendlier, adaptable and safer working environment or condition for the learners to operate in, thus, reducing the risk of them physically getting injured. The learners will also tend to be less stressed when training is conducted via simulator, since they know that any mistakes or errors committed during the training will not cause disastrous and harmful impacts.”
MMC-Gamuda says that concerns were raised by some parties with respect to the gaps in terms of practical applications between virtual and reality, but experience has shown that the simulator really does make production more efficient.
“On top of this, with the digital record system available for every ring build, it enables the trainer and the TBM shift operator to study the difficulties faced by a majority their trainees and give a more accurate assessment”.
