Trenchless technology

Trenchless technology, as the name implies, stands for subsurface construction works where less trenches or no continuous trenches are required to be dug. It is a rapidly growing sector of the construction and civil engineering industry. It can be defined as "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." [ http://www.nastt.org/ North American Society for Trenchless Technology]

Trenchless construction

Trenchless construction refers to such construction methods as tunneling, microtunneling (MTM), horizontal directional drilling (HDD) also known as directional boring, pipe ramming (PR), pipe Jacking (PJ), moling, horizontal auger boring (HAB) and other methods for the installation of pipelines and cables below the ground with minimal excavation. Large diameter tunnels such as those constructed by a tunnel boring machine (TBM), and drill-and-blast techniques are larger versions of subsurface construction. The difference between trenchless and other subsurface construction techniques depends upon the size of the passage under construction. If a subsurface construction does not permit human entry it is termed as trenchless.

Trenchless rehabilitation

Trenchless rehabilitation refers to such construction methods as sliplining, thermoformed pipe, pipe bursting, shotcrete, gunite, cured-in-place pipe, grout-in-place pipe, mechanical spot repair, and other methods for the repair, rehabilitation, or replacement of existing buried pipes and structures without excavation, or at least with minimal excavation. Sliplining and thermoformed pipe lining involve pulling a new liner through an existing pipe, then applying heat and/or pressure to force the liner to expand to fill the pipe. Pipe bursting fractures a pipe from the inside and forces the fragments outwards while a new pipe is drawn in to replace the old. [cite paper
url=http://www.ttc.latech.edu/publications/guidelines_pb_im_pr/bursting.pdf
date=March 2001
publisher=U.S. Army Corps of Engineers Engineering Research and Development Center
author=Simicevic, Jadranka and Sterling, Raymond L.
title=Guidelines for Pipe Bursting,TTC Technical Report #2001.02 ] The other methods are primarily for fixing spot leaks.Trenchless rehabilitation methods are generally more cost-effective than traditional exhume (dig) and replace methods.

The trenchless technology industry is represented by several industry associations in addition to standing committees within almost every water and sewer related industry association. The National Association of Sewer Service Companies was established in 1976 and is the oldest such association with a trenchless focus. The Indian Society for Trenchless Technology or IndSTT is the apex organization to promote Trenchless Technology in South Asia. It was established in 1995 with its head office at New Delhi. The International Society for Trenchless Technology, established in 1986, has 25 active [http://www.istt.com/index.cfm?menuID=32 national trenchless technology societies] associated with it. Several organizations bring out Technical Journals for sensitizing the readers about such techniques. [http://www.indstt.org/ndi.html No Dig India] is the official Journal of IndSTT.

References

External links

* [http://www.redzone.com/trenchless Trenchless Technology, what is it anyway?]
* [http://www.indstt.org/ Indian Society for Trenchless Technology]
* [http://www.ukstt.org.uk/ United Kingdom Society for Trenchless Technology]
* [http://www.cuire.org/ Center for Underground Infrastructure Research and Education CUIRE]
* [http://www.perco.co.uk/ Perco - The UK leader in trenchless technology]