Rules and standards for micro-tunnelling
Careful preparation in terms of planning and formulating invitation for tender documents form an important initial stage if a micro-tunnelling project is to be realised successfully. At the same time such careful preparatory work permits the companies tendering to cost their work optimally. In DIN 18319 "Micro-tunnelling", which is a component of VOB part C, the following points are laid down amongst others:
Details of the site by the client
- Billing units
- Recent grading of soil and rock in terms of their suitability for microtunnelling
- Requirements for the mode of execution, e.g. applicable procedure in the case of variances from the agreed reference axis or in the case of obstacles arising
- Billing
ATV (Technical Waste Water Association) working sheet A 125 "Microtunnelling" is based on DIN 18319 but goes significantly further in its statements. In addition to describing unmanned and manned microtunnelling systems, it lays down requirements in terms of:
- Construction and mechanical devices
- Jacking pipes, jacking pipe connections and shafts
- Preparatory planning
- Execution by the contractor
Further themes are:
- Microtunnelling under the lines of German Railways
- Microtunnelling under federal main roads and motorways
- Microtunnelling under federal canals
The ATV working sheet as an important set of rules for planning and executing projects is now serving as the foundation for a European set of rules for microtunnelling.