An Introduction to Trenchless Technology

In the past decade, the field of trenchless technology has expanded rapidly in products, equipment, and utilization. This expansion would not have occurred without a strong increase in economic incentives to the user. Because the operating environment has changed, trenchless technology is often the preferred alternative to traditional methods of digging holes and installing conduits. The infrastructure in which we live has become more congested and has to be shared by several users. In addition, the cost of restoring a road or landscaped area after construction may be higher than the cost of installing the conduit. These factors add to the need for trenchless technology-the ability to dig holes without disturbing the surface. In some ways, trenchless technology is a futuristic concept. Ruth Krauss in a children's book of definitions wrote, "A Hole ...Is to Dig." But this statement is not necessarily true. Today, a hole could be to bore.

1 Introduction and Overview.- 1.1 Need for Trenchless Technology.- 1.2 Horizontal Boring Techniques.- 1.3 General Procedures.- 1.4 Selection of Method.- 1.5 Limitations.- 1.6 Future Outlook.- 1.7 Looking Ahead.- 2 Background.- 2.1 Early Underground Work.- 2.2 The Stimulus of the Industrial Revolution.- 2.2.1 The Beginning of Utilities.- 2.2.2 Developing Underground Methods.- 2.2.3 Inventors.- 2.2.4 Mechanical Drills.- 2.3 Early Trenchless Methods—1890–1960.- 2.4 Trenchless Methods—1960–1985.- 2.4.1 Sewer Installation Methods.- 2.4.2 Installation Methods for Cable and Pressure Pipes.- 2.4.3 Trenchless Rehabilitation.- 3 Creating the Hole.- 3.1 Thrust Boring.- 3.1.1 Description of Equipment and Operation.- 3.1.2 Specifications of Bore.- 3.1.3 Selection/User Considerations.- 3.1.4 Typical Applications.- 3.2 Impact Moling.- 3.2.1. Description of Equipment and Operation.- 3.2.2 Specifications of Bore.- 3.2.3 Selection/User Considerations.- 3.2.4 Typical Applications.- 3.3 Impact Ramming.- 3.3.1 Description of Equipment and Operation.- 3.3.2 Specifications of Bore.- 3.3.3 Selection/User Considerations.- 3.4 Rock Hammer.- 3.4.1 Description of Equipment and Operation.- 3.5 Auger Boring.- 3.5.1 Description of Equipment and Operation.- 3.5.2 Specifications of Bore.- 3.5.3 Application and User Considerations.- 3.6 Wet/Slurry Boring.- 3.6.1 Description of Equipment and Operation.- 3.6.2 Specifications of Bore.- 3.6.3 Selection/User Considerations.- 3.6.4 Typical Applications.- 3.7 Fluid Jet Cutting.- 3.7.1 Description of Equipment and Operation.- 3.7.2 Specifications.- 3.7.3 Selection/User Considerations.- 3.7.4 Typical Applications.- 3.8 Pipe Jacking and Microtunnelling.- 3.9 Rotary/Directional Drilling.- 3.9.1 Description of Equipment and Operation.- 3.9.2 Specifications.- 3.9.3 Selection/User Considerations.- 3.9.4 Typical Applications.- 4 Steerable Horizontal Boring.- 4.1 Methods of Steering the Bit.- 4.2 Available Systems.- 4.2.1 Guided Impact Mole.- 4.2.2 Impact Mole on Pipe.- 4.2.3 Directional Rod Pushers.- 4.2.4 Directional Fluid Jet Cutting.- 4.2.5 Directional Drilling.- 4.3 Planning the Job.- 4.4 Applications.- 4.5 Preventing and Controlling Problems.- 5 Pipe Jacking and Microtunnelling.- 5.1 Pipe Jacking.- 5.1.1 Definition.- 5.1.2 Background.- 5.1.3 Pipe-Jacking Method.- 5.1.4 Main Applications of Pipe Jacking.- 5.1.5 Selection Criteria and Summary.- 5.2 Microtunnelling.- 5.2.1 Definition.- 5.2.2 Classification.- 5.2.3 Pipe Installation.- 5.2.4 Techniques.- 5.2.5 Pilot Method.- 5.2.6 Full-Face Method.- 5.2.7 Performance factors.- 5.2.8 Main Applications of Microtunnelling.- 5.2.9 House Connection Systems.- 5.2.10 Full-Face Machines.- 5.2.11 Full-Face Microtunnelers.- 6 On-Line Replacement and Structural Renovation.- 6.1 Introduction.- 6.2 Options.- 6.3 On-Line Replacement.- 6.3.1 Background.- 6.3.2 Extraction.- 6.3.3 Bursting.- 6.3.4 Hydraulic Bursters.- 6.3.5 Excavation Replacement.- 6.3.6 Melbourne System.- 6.4 Renovation.- 6.4.1 Background.- 6.4.2 Conventional Slip Lining.- 6.4.3 Modified Slip Lining.- 6.4.4 Soft-Lining Systems/Cured-In-Place Pipe.- 6.4.5. Alternative Systems.- 6.4.6 Temporary Reduction Methods.- 6.4.6.1 Diameter Reduction.- 6.4.6.2 Collapsed or Folded Sections.- 6.4.7 Spiral Winding.- 6.4.8 Spraying.- 7 Instrumentation Systems for Guided Boring.- 7.1 Unguided Systems.- 7.2 Guided Boring.- 7.2.1 Instrumentation Requirements.- 7.2.2 Measurement Considerations.- 7.3 Guidance Instrumentation Systems.- 7.3.1 Pipe Locators.- 7.3.2 EM Home-to-Target Steering Tool.- 7.3.3 Laser Targeting System.- 7.3.4 Single-Shot/Multishot Survey Tools.- 7.3.5 Steering Tools.- 7.3.6 Measurement-While-Drilling (MWD) Systems.- 7.4 Equipment Selection.- 7.5 Needs and Future Trends.- 8 Economics of Trenchless Technology.- 8.1 Economic Costs.- 8.2 Open-Cut Method.- 8.3 Economic Studies and Models.- 8.4 Effect of Drilling Rate.- 8.5 System Utilization.- 9 Investigation, Routing, and Location.- 9.1 Selection of Trenchless Equipment.- 9.2 Planning and Design of Project.- 9.3 Job Implementation and Precautions.- 10 Case Histories.- 10.1 Case History 1: Horizontal Drilling.- 10.1.1 Description.- 10.2 Case History 2: Guided Piercing Tool.- 10.2.1 Description.- 10.3 Case History 3: Microtunnelling.- 10.3.1 Description.- 10.4 Case History 4: Pipeline Insertion Machine.- 10.4.1 Description.- 10.5 Case History 5: UTILX Guidedril Tunnelling Machine.- 10.5.1 Description.- 10.6 Case History 6: Microtunnelling.- 10.6.1 Description.- 10.7 Case History 7: Renovation.- 10.7.1 Description.- 11 Future Needs.- 11.1 The Future in Perspective.- 11.2 Attitudes and Awareness.- 11.2.1 Lack of Awareness.- 11.2.2 Resistance to Change.- 11.2.3 Responsibilities for Social Costs.- 11.2.4 Engineering and Planning.- 11.2.5 Costs of Work.- 11.3 Technical Needs.- 11.3.1 Investigation.- 11.3.2 Costs of Trenchless Methods.- 11.3.3 Improved Technology.- 11.3.4 Service Connections.