What is Trenchless Technology
Trenchless technology is a method of repairing and rehabilitation or installing pipelines or cables under the street or buildings, without disturbing the structure on top. This system has evolved as a result of alternative methods, that were being put into action by engineers for rehabilitation of structures under streets. It is often defined as a family of methods that is used to install or repair structures under the streets.
Trenchless tunneling is often put to use in big cities, especially for busy streets. It mainly resorts to methods like tunneling, micro tunneling, horizontal drilling, pipe ramming, jacking, and horizontal auger boring. The process of rehabilitating or constructing structures, with the help of trenchless technology, is not very difficult. In the process of construction, two pits are dug at the end points between which the pipeline or cable is to be placed, under the street. The first pit is termed as ‘intersection pit’ and the second is termed as ‘reception pit’. Device that is similar to a mechanical mole is inserted into the intersection pit. The mole drills a tunnel till it reaches the reception pit. The drilled, dirt and rubble is then removed by a device that works like an excavator. This process of tunneling is often referred to as micro tunneling. The coil and loop of a winch or a puller is passed from reception pit to intersection pit. The pipeline or cable that is to be laid or construed is made up of flexible and sturdy material. The coil of the puller is attached to the end of the cable and is inserted in the tunnel. The puller keeps on pulling the cable or pipeline till it reaches the receiving pit. After it has been suitably laid down and both ends of the cable or pipeline have reached respective pits a miniature concrete chamber is created in both pits.
In case of repairs, the pulling machine first extracts the damaged cable, and then a new one is placed in the micro tunnel. If a pipeline is supposed to be removed, then the excavating machine, known as ‘bursting head’, first removes the debris of the broken pipeline and then a new one is placed inside.
Some of the other methods that are also deployed are, sliplining, mechanical spot recovery, where the whole pipeline is not replaced but, the damaged section is repaired. Another method that is used is shotcrete, in which concrete or sealing material is conveyed inside the pipeline with the help of a pressurized hose. Spot leaks or cracks in the pipeline can be easily repaired with the help of shotcrete.
Advantages of Trenchless Technology
The trenchless technology, as mentioned above, was developed to aid the repair work of pipelines and cables situated under the street in big cities. The biggest advantage of trenchless technology is that, it does not disrupt traffic, as done in normal construction methods in which a trench is dug up for repair. Trenchless technology is also efficient in saving resources, as the street that is dug up does not have to be repaired or reconstructed. It is also a very simple process that does not involve complex techniques and highly skilled man power. The construction work also does not take a long time, and is completed easily and quickly.
The trenchless technology or the ‘no dig’ technology, is slowly coming to prevalence due its many merits. However, the equipment that is used is still costly.
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