Microtunnelling can be a tricky game. Determining what lurks beneath the ground prior to a project commencing is far from an exact science, and sometimes even the most skilled and well-prepared microtunnelling contractors will come across situations they may not be prepared for.
Countless foreign objects lie hidden underground and sometimes project owners are unaware of the ground conditions or history of a site.
Whose problem is it anyway?
When unexpected complications do occur, there is often a case of confusion regarding who is accountable and required to solve them. What is the best way to share potential risks and ensure that the best outcome for all parties involved?
Firstly, a microtunnelling contractor should always be as prepared as possible. Before commencing any microtunnelling job, researching the ground conditions thoroughly is a crucial step.
However, it’s also not unusual for us to come across foreign objects underground that could not have been predicted.
What lies beneath
During a recent job in Logan, Queensland, Edge Underground was completing a microtunnel under a two-way motorway. In the middle of the motorway it was discovered that the ground was packed with rubbish, and that the area had been treated as a tip many years before and was filled with rubbish, water and unstable ground.
These ground conditions proved to be a nightmare for all involved.
The geotechnical surveying works completed prior to the microtunnel project had not detected the rubbish conditions. Although Edge Underground was able to complete the job, it added unforeseen costs that had to be factored into the contract.
During this case Edge was able to negotiate with the head contractor and the project owner so that the costs of the additional works could be shared amongst all three parties.
Lesson to be learned
The important lesson to take from this project is this – always build flexibility into your project contracts for unexpected ground conditions. It can’t be the responsibility of one party alone to bear all the risk if the job turns out to have different requirements than expected.
Make sure you’re protected as a contractor, and arrive on the job site with the spirit of collaboration in mind from the outset.
If everyone is arguing about whose responsibility a problem is, no one is working and everyone is losing money. The sooner the problem is solved, the sooner everyone is back to work!