1. INTRODUCTION TO TRENCHLESS TECHNOLOGY

2. Traditional Methods First suited for “gre enfield”
Low tech – little change over past 50 yrs.
Level of planning & implementation basic
“Non-greenfield” – surface disruptions, underground utilities

3. Trenchless Technologies
Thrust Boring & Pipe Jacking (pre-1900’s)
Auger Boring (1940)
Impact Moling (1962)
Directional Drilling (1971)
Impact Ramming (1980)
Pipe Bursting (1980’s)

4. Definition of Trenchless Technologies
“A family of methods, materials, and equipment capable of being used for the installation of new or replacement or rehabilitation of existing underground infrastructure with minimal disruption to surface traffic, business, and other activities.”

5. New Construction Techniques
H.D.D.
Pipe Bursting
Micro tunneling
Pipe Jacking
Auger Boring

6. Horizontal Directional Drilling
Lengths of m
Diameters of mm
Applications:
utility conduits
Pipelines
gravity sewers
force mains
horizontal remediation wells
geotechnical investigations

7. HDD Process

8. HDD Process

9. Pipe Bursting Lengths of 100 - 900 m Diameters of 75 - 1060 mm
Applications:
replacement of force mains
replacement of gravity sewers
Static Head
Pneumatic Head
Hydraulic Head

10. Pipe Bursting Process(Static)

11. Pipe Bursting Process(Static Cont.)

12. Pipe Bursting Process(Pneumatic)

13. Microtunneling Lengths of 25 - 225 m Diameters of 250 - 3050 mm
Applications:
gravity sewer installations

14. Microtunneling Process

15. Pipe Jacking Lengths of up to 490 m have been achieved
Diameters of mm
Applications:
large diameter gravity sewers and force mains

16. Pipe Jacking Process

17. Auger Boring Lengths of 12 - 150 m Diameters of 200 - 1500 mm
Applications:
relatively short crossings of pipes and conduits

18. （一）Pipe Bursting （二）Horizontal Directional Drilling
TWO CASE HISTORIES
（一）Pipe Bursting
（二）Horizontal Directional Drilling

19. Alternatives
Parallel the existing gravity trunk sewer with a new gravity trunk sewer
Construct a series of 5 new pumping stations and pump to adjacent sewerage area

20. Parallel Trunk Sewer Advantages Maintains gravity flow Disadvantages
Construction in silty sand to clayey material 3 to 6 metres deep with high groundwater in close proximity to Millstone River, a highly sensitive Coho salmon habitat stream.
Additional right-of-way would be required
Cost Estimated at $5.1 million

21. Pumped Option Advantages
Minimizes environmental impacts as pump stations and forcemains for the most part would be constructed in existing right-of-ways.
Disadvantages
Added undesirable long term operational costs to the City of Nanaimo
Cost Estimated at $5.2 million

22. Pipe Bursting Researched as a Possible Alternative
Advantages
Less environmental impact as excavation is minimized
Gravity flow maintained
No additional right-of-ways required
No long term operational and maintenance costs associated with pump stations
More cost effective than alternatives
Disadvantages
Upsize required at the upper limit of PB technology in North America; however, there had been limited success
Lengths 100m to 175m
Limited availability of contractors in North America with capability to perform upsize of this nature

23. Demonstration Section
Ability to burst project lengths (100m to 175m)
Ability to burst pipe couplings
Ability to burst concrete encasement
Although some difficulties encountered, remaining project was subsequently awarded

27. 650mm
(26”)
750mm
(30”)
350mm
(14”)