INTRODUCTION TO TRENCHLESS TECHNOLOGY

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

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)

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.”

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

Horizontal Directional Drilling Lengths of 15 - 1800 m Diameters of 25 - 1200 mm Applications: utility conduits Pipelines gravity sewers force mains horizontal remediation wells geotechnical investigations

HDD Process

HDD Process

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

Pipe Bursting Process(Static)

Pipe Bursting Process(Static Cont.)

Pipe Bursting Process(Pneumatic)

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

Microtunneling Process

Pipe Jacking Lengths of up to 490 m have been achieved Diameters of 1060 - 3050 mm Applications: large diameter gravity sewers and force mains

Pipe Jacking Process

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

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

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

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

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

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

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

650mm (26”) 750mm (30”) 350mm (14”)