NASCLA Accredited Commercial General ContractorSite WorkHard
A project manager is overseeing the installation of a large diameter storm sewer pipe in an urban environment. The project requires minimizing disruption to traffic and existing utilities. Which trenchless technology would be most suitable for installing the pipe under these conditions?
- APipe bursting
- BDirectional boring (HDD)
- CMicrotunneling
- DOpen-cut trenching
Show answer & explanationAnswer & explanation
Correct answer: C. Microtunneling
Microtunneling is a trenchless method that is ideal for installing large diameter pipes (typically 36 inches and larger) with high accuracy, minimal surface disruption, and in congested urban areas. Unlike HDD, it is suitable for larger pipes and more precise grade control.
Why the other options are wrong
- A. Pipe bursting is used for replacing existing pipes with new ones of the same or larger diameter, not for installing new pipes in a new alignment.
- B. Directional boring (HDD) is primarily for smaller diameter utilities (up to 36 inches, but usually smaller) and generally has less precise grade control than microtunneling, making it less ideal for large storm sewers needing specific slopes.
- D. Open-cut trenching causes significant disruption and is what trenchless technologies aim to avoid.
Microtunneling
A trenchless construction method used to install pipelines by jacking pipe segments behind a steerable, remotely controlled tunneling machine, with continuous spoil removal.
- Suitable for large diameter pipes (typically >36 inches).
- Offers high accuracy and precise grade control.
- Minimizes surface disruption in urban areas.
Memory trick: Boring for Small, Micro for Big, Bursting for Old, Jacking for New.