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)
28 juillet 2017
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
19/04/2007
2
Diapo 2
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
Placement in narrow trench with recycling of
material (DVGW / Gaz de France project)
Urban environment
• High traffic density
• Construction machinery adapted to town centres
• Large number of obstacles in the soil (particularly under
the pavement)
Laying at shallow depth (Gaz de France /ETDE project)
19/04/2007
3
Diapo 3
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
19/04/2007
4
Diapo 4
Essential aspects of the research project
Comparison of guide lines and required
performances in France and in Germany
19/04/2007
5
Diapo 5
Essential aspects of the research project
Treatment of excavated soils for re-employment as
backfill material
19/04/2007
6
Diapo 6
Essential aspects of the research project
Long term study of the behaviour of recycled
materials
• Study of the « re-excavability »
19/04/2007
7
Diapo 7
Essential aspects of the research project
Quality control ( Q.C)
19/04/2007
8
Diapo 8
Facilitate laying conditions in suburban
environment
Narrow trench site – depth
according to regulation
Study of self compacting
materials based on recycled
excavated materials (Germany)
19/04/2007
9
Diapo 9
Definition of technical-economic recycling
conditions
Facilitate laying conditions in urban environment
with new self-compacting concrete in shallow trenches
PATENTED WITH ETDE
19/04/2007
10
Diapo 10
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
19/04/2007
11
Reopen for trafficDiapoat11 the end of the day
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
AIR DEFENCE
19/04/2007
12
Diapo 12
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)
19/04/2007
13
Diapo 13
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
19/04/2007
14
Opportunities to use, in Europe, new technologies
with evolutions of laying rules for the distribution
gas pipes
Diapo 14