D K Gautam, Retired Scientist, CSIR-CBRI, Roorkee.
Trenchless construction is a method of laying services under the ground without disturbing the surface structures. The imported underground horizontal drilling machines are available in high capacities and suitable for large size bores only. There is a need for making small size bore under the ground in construction industry and no small capacity machine is available. To cater the need, an underground horizontal boring machine has been developed at the Institute, specifically, for construction activities such as laying sewer pipelines, conduits, water pipe line etc. The same has been described in this paper. The machine is capable of making horizontal bores in dry state using open flight auger as well as in wet state using a cutter along with water jet. The developed machine is capable to carry out the under ground jobs effectively which cater the needs of small to medium contractors engaged in building and allied construction activities such as laying sewer pipe lines, conduits, electric cables, water pipe lines etc. under building and roads.
Trenchless construction is a method of laying services under the ground without disturbing the structures on the surface. The amount of excavation and the surface repairs are minimized, which are otherwise needed after digging when open trenching is used for laying underground utilities. At present, the installation, inspection, repairs and replacement of underground services involve open trenching construction method, but, these operations are very expensive and slow. The additional cost is also incurred to restore the existing surfaces and repairs resulting from the ground settlement. Beside from the associated high costs, open cut trenching operations often result in high user or social costs due to the disruption to traffic and the adverse impact on nearby area. Trenchless methods allow the installation of most underground infrastructure systems with minimum surface disruption. As per the North American Society of Trenchless Technology, the trenchless construction is a family of methods, materials and equipment capable of being used for the installation of new or replacement of existing underground infrastructure with minimum disruption to surface traffic, business, and other activities. Making bores under the ground using trenchless methods has in general the following major advantages –
- No hindrance to the activities going on at the surface.
- Environmental issues are minimized.
- Safety concerns associated with open cutting are eliminated.
- Fast and economical.
The trenchless methods can be divided into two general categories:
- The installation of new facilities.
- The inspection, repair and up-gradation of existing facilities.
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