Introduction

• Trenchless technology methods include all methods of installing or renewing underground utility systems with minimum disruption f the surface or subsurface.
• Trenchless technology consist of various methods, materials and equipment for inspection, utilization and rehabilitation.
• Trenchless technology has become popular for underground utility construction road crossings.
• In recent years, there has been remarkable progress in development of new trenchless technology equipment and methods.

Objective of Trenchless Technology

• Cost-effectiveness
• Ease of Design
• Production Rates
• Extends Underground Assets
• Benefits Environment

Site Investigation

Common problems at site are,

• Loss of invert walls, ceilings due to corrosion
• Leaking joints
• Settlement
• Shape deformation
• In adequate flow capacity
• Voids in embankment around and above the culvert

Hence before take the trenchless excavation work the site investigation must be made.

Techniques in Laying of Pipes

1. Pipe Jacking

The term pipe jacking can be used to describe a specific installation technique as well as a process applicable to other trenchless technology.

2. Auger Boring

If there are longer boring to be carried out or if the drilling precision has to be higher the borings are carried out as guided auger borings.

3. Micro Tunneling

Pipes are jacked from a launch pit to a reception pit by means of a hydraulic jacking station in the launch pit.

4. Pipe Ramming

Pipe ramming involves the use of the dynamic force and energy transmitted by a percussion hammer attached to the end of a pipe.

Utility Tunneling

The procedure consists of four major steps-

• Soil excavation
• Soil Removal
• Segmental liner installations
• Line and grade control

Advantages of Trenchless technology

• Expenses and dates are much easier to calculate.
• Surface life stays mainly undisturbed.
• Up to 95 percent lesser load for landfills due to minimal excavations.
• Small stress for streets and traffic.
• Minimization of CO2 emissions.