Underground Cable Laying Using HDD Method

How to use Horizontal Directional Drilling for Underground Cable Laying?

Horizontal directional drill construction trenchless method of installing pipelines in areas where traditional open-cut excavations are not feasible for environmental or logistical reasons. It is commonly used for the installation of pipelines beneath rivers, highways, railroads, and other environmentally sensitive areas, including steep bluffs where elevation changes over short distances compromise the conventional cut and cover installation.

Horizontal directional drilling (HDD) could be a special technique for the installation of underground utilities, which may considerably save time and cash. To do this, use a run-of-the-mill tool and therefore the hollow steel rod which may bend underneath the management of measuring device systems in the right direction. HDD technique was used for the primary time in America, within the middle of the last century, was then with success arranged a cable underneath the watercourse.

In our country saw a plus of such drilling recently, however currently it's bit by bit exchanging alternative ways that involve the heap of soil, significant instrumentality, and therefore the destruction of roads or tramways. HDD technique isn't a terrible town with dense buildings, landscapes, or any road.

Horizontal directional drilling is employed in several fields:

• for the development of communications residential complexes (sewer, water, electrical cable)
• energy firms (cable laying)
• organizations that give communication services.

Drilling rigs will lay a trench underneath the bottom, river, road, and fence. this offers nice blessings to the current technique, it's not necessary to dig AN open trench and do mine for communications. For the parturition of cable don't ought to rent an oversized range of individuals, that reduces the method. Communications this technique may be run in any weather, as a result underneath the bottom, there's no temperature below zero at any time of the year. Rain additionally won't be a hindrance, because the water within the underground trench won't fall.

In order to provide horizontal directional drilling, can like loads of functionary procedures. These sorts of works will turn out solely for firms with a license. most frequently they're engaged in the registration of all necessary permitting documents.

A drill set up of the ditch to be in agreement in several organs, to not get harm the opposite communications at work. The theme arranged communications is creating in its base Service of Cable lines, you furthermore may prepare everything properly within the town that area unit engaged within the issuing of permits for geologic analysis and mapping of underground formations (Mosgorgeotrest).

On drilling rigs wear a special nozzle drilling tool that permits you to drill a cavity of the specified diameter. initial could be a slender nozzle, that is underneath the management of the locating device out of the bottom within the right place. alongside the passage of the piercing nozzle into the opening within the concrete grout underneath air mass, which reduces the friction of the tool regarding the breed.

Using special extenders and re-drilling are needed for the diameter of the ditch. within the third stage, into the cavity underneath the bottom arranged the required communications, protected by a plastic tube. It may be optical cable or plastic, or iron pipes.

The horizontal directional drilling technique is of special technology necessity of the method. It is arranged the ditch for the cable, then it mustn't be over 3 cables. the space between the underground trenches mustn't be but one meter. the ditch is arranged at a distance of not but a meter from alternative underground utilities. At the top of underground pipes should be created the top caps (plugs). every kind of cable features a bending radius, as a result, the drilling of the ditch should take this into consideration.

Horizontal directional drilling may be referred to as a technology of the long run, that significantly facilitates and accelerates work on the parturition of underground cable.

What are the disadvantages of Using HDD for Underground cable laying?

Consider the following example of laying underground cable in between two substations as figure:

Cable Specification:

1. Rated voltage 132kV;
2. Number of Circuits 2 nos;
3. Number of Cables per circuit 3 nos;
4. Number of FOC cable 2 nos
5. Cable diameters 115 mm;
6. Weight of cable per meter 16.7 kg;
7. Cable drum length 514 m;
8. Cable Laying depth 1.5m

HDD Pipe Specification:

1. Pipe diameter 160 mm;
2. Number of pipes 7 nos;
3. Cable Laying depth 6 to 8m

Limitation of Using HDD for Cable Laying

1. HDD drilling length is limited to up to 200m whereas cable length is more than 500m;
2. HDD pipe can not bend as required to Cable;
3. Open trench need 1.2m width & 1.5m depth trench; 
4. HDD needs 3m width & 6/8m depth space
5. Cable trefoil formation is not possible at HDD that is a technical requirement;
6. Multiple winches are not possible to use in HDD for cable pulling;
7. Single winch use may cause cable sheath damage;
8. Faulty cable/cable sheath finding and repairing at 6/8m depth is very difficult;

Horizontal directional drilling or HDD is a steerable trenchless method of installing underground cables in a shallow arc along a prescribed bore path by using a surface-launched drilling rig, with minimal impact on the surrounding area.

The aforementioned drawing for a project of the company includes completion of HDD for the river, railway, canal, national highways, etc.

History of HDD

As the need for water and sewer services grew during the 1950s, 1960s, and 1970s, civil engineers were faced with the task of connecting treatment plants on one side of the river with customers on the other side (Bennett, 2003.) In “How the HDD Industry Began,” author Martin Cherrington describes how he conceived the use of horizontal directional drilling as a practical alternative to conventional trenching methods beginning in the 1960s. (Cherrington) While working for a contractor in the Los Angeles area in 1963, Cherrington realized that there might be potential for using drilling technology to greatly enhance the efficiency of placing cables and conduits underground. This observation would spark an idea that ultimately would launch a whole new industry, horizontal directional drilling. In 1964, Cherrington built his first drill rig and formed Titan contractors, a company specializing in utility road boring in Sacramento, California.