How can contractors using larger microtunnelling machines meet specifications when tolerances are tight?
For larger microtunnelling machines, German standards quote 50mm from the design line. However, some contractors feel this tolerance is too restrictive for large machines - such as say an AVN 2400 which could weigh some 50 tonnes - especially when tunnelling through soft, mixed soils. When using such machines, there is limited data that contractors can access to assess ground conditions, so ultimately accuracy will come down to experience and ensuring the client understands the achievable installation tolerance. The major problem with projects where the microtunnelling machine is cutting through soft, mixed soil, is that there is not really an...
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Balancing the triple constraint on pipeline installations
Quality, time and cost. These three competing factors — often referred to as the triple constraint — are always front-of-mind of clients when they are seeking contractors to carry out project works. While clients would like to be able to meet all three, this is rarely possible. This holds true for pipeline installations. However, as Stuart Harrison the Managing Director of Edge Underground explains, the key for pipeline installations is finding a contractor that is able to balance these constraints to get a quality installation while remaining on time and on budget. “While in the past people considered the general...
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How to change the cutter head of the microtunnelling machine when there is a hard rock in between the drive...
It is not uncommon for microtunnelling contractors to arrive on site and find the ground conditions are different to the geotechnical information provided. This is problematic for most microtunnelling projects as most machines are not designed to allow easy access to the cutter head once an installation has started. So if you don’t have the right equipment and you encounter rock, project costs and time can increase. Microtunnelling, as a trenchless installation method, by nature is non-man entry, so contractors do not have the ability to get up to the cutter head physically in order to change the tooling. This...
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Top benefits of pipe jacking
Pipe jacking is a trenchless pipeline installation method that has gained popularity as an alternative to open cut methods in urban areas where existing infrastructure needs to be navigated and disruption to residents needs to be minimised. Here, we look at the environmental, urban and safety benefits of pipe jacking, and why it should be considered over other methods of pipeline installation. What is pipe jacking? Pipe jacking is a non-disruptive method of installing pipes where the pipe is directly installed in a continuous length behind a machine while controlled excavation takes place at the face. The result is a...
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Minimising disruptions and maximising accuracy with microtunnelling
In crowded urban areas, the installation of underground utilities can pose major disruption to the community and the surrounding environment. When considering environmental concerns and community impact, trenchless technologies such as microtunnelling can help mitigate concerns by minimising disruptions. It also benefits asset owners by reducing time costs and increasing accuracy. In the past, when considering the installation of underground utilities contractors didn’t have access to trenchless technologies, and therefore more disruptive methods of installation were used, such as open cut trenching. Microtunnelling now offers an alternative, sustainable solution for installing pipelines quickly, accurately and with minimal disruption. Considering the...
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Five things to consider before starting a microtunnelling job
There are several things to consider before undertaking a microtunnelling installation that influence accuracy, downtime and costs. Here, Stuart Harrison, Managing Director at Edge Underground, looks at five critical considerations that need to be taken into account to achieve a successful installation. An accurate guidance system Without a highly accurate installation method, projects with tight tolerances are at risk of costly installation failures. When it comes to accuracy, microtunnelling is unrivalled in the industry as it utilises a laser guided system to achieve an accuracy of +/-25mm, with the Vermeer AXIS guided boring system commonly achieving +/-10mm accuracy on...
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No room for error: microtunnelling vs HDD considerations
Trenchless technology has been quickly growing in popularity due to its vast environmental, cost and time benefits. When selecting which technique, such as microtunnelling or HDD, to use for a pipe installation there are differences that need to be considered. Here, we look at the types of considerations that should be made when selecting the right trenchless solution. Line of installation There are many practical considerations when choosing between microtunnelling and HDD for pipe installations. One of the main considerations is the line the pipe needs to take. Microtunnelling machines are built to install pipe in a straight-line from pit...
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