New Gas Works Concepts: The examples of minimal trenching

1. New Gas Works Concepts: The examples of minimal trenching Franck Groeschl ( DVGW – Bonn) - Hartmut Reichenbach (S&P - Stuttgart) Jean-Pierre Capdevielle ( Gaz de France – Saint Denis)

2. Improve safety and quality of urban works:with a global approach to the works function • Improve the safety of gas networks • Facilitate identification of existing structures • Improve passive protection of networks • Limit the impact of works for neighbours • Hindrance to traffic (car and pedestrians) • Works duration - Reduce the environmental impact • Reduce the environmental impact • Reduction in volumes of waste • Reduction in borrow quantities • Improve economic efficiency • Direct cost during laying • Indirect cost, reducing risks to third parties

3. Consideration of the site typology Optimisation of the trench geometry • Suburban or rural • Few traffic constraints • Possibility of bringing in large construction machinery • Few obstacles in the soil • Urban environment • High traffic density • Construction machinery adapted to town centres • Large number of obstacles in the soil (particularly under the pavement) Placement in narrow trench with recycling of material(DVGW / Gaz de France project) Laying at shallow depth(Gaz de France /ETDE project)

4. Minimal intrusion into roadways while ensuring optimum quality and reduction of costs • Aim of the research project «Minimal Trenching »: • Determine the construction methods for minimal intrusion • Optimise quality assurance for street works and pipe laying Professional guideline with a view to harmonisation of French-German standards

5. Essential aspects of the research project • Comparison of guide lines and required performances in France and in Germany

6. Essential aspects of the research project • Treatment of excavated soils for re-employment as backfill material

7. Essential aspects of the research project • Long term study of the behaviour of recycled materials • Study of the « re-excavability »

8. Essential aspects of the research project • Quality control ( Q.C)

9. Facilitate laying conditions in suburban environment Narrow trench site – depth according to regulation Definition of technical-economic recycling conditions Study of self compacting materials based on recycled excavated materials (Germany)

10. Facilitate laying conditions in urban environmentwith new self-compacting concrete in shallow trenches PATENTED WITH ETDE

11. A technique in service already tested internationally(Switzerland, U.K.) • 1 km done in narrow trench – 50 cm deep • « Just-in-time & short » site minimising nuisance to neighbours • Reopen for traffic at the end of the day

12. Knowledge of the soil before the work GIGA and ORFEUS : Two european projects with PCRD to federate the best skills Objectives:to characterise the performances of existing radar systems and develop new systems capable of satisfying user needs

13. Knowledge of the soil before the work GIGA and ORFEUS : Two european projects with PCRD to federate the best skills • Tests in controlled environment • An environment adapted to performance tests • 20 to 160 mm diameter tubes (PE, steel, cast iron) • 20 cm to 2 meters deep (positioned with precision) • 4 different types of soil (sand, earth, clay-lime, fill) • 2 surface types (coated chippings,soil)

14. Conclusions with these 3 R&D GERG Projects : Placement in narrow trench with recycling of material + Laying at shallow depth with new self compacting concretes + Optimised GPR to find every distribution networks under the streets Opportunities to use, in Europe, new technologies with evolutions of laying rules for the distribution gas pipes