Main advantages of the HDD method
Production and technical aspects
1. The possibility of trenchless construction, repair and rehabilitation of underground utilities:
- Under the rivers, ravines, forests, and in the specific ground (rocks, floaters);
- In protected areas of high overhead power lines, the main gas, oil and product pipelines;
- In dense urban housing development by passing under the motorway route, tram tracks, roads, squares and parks;
2. Shortening time and amount of organizational and technical approvals before starting work, because the absence of the need to stop the movement of all types of land transport, blocking roads and railways;
3. Considerable reduction of work production time due to the use of high-tech drilling equipment;
4. Significant reduction in the amount of heavy equipment and labor, attracting for pipelines building;
5. Reducing the risk of accidents and, therefore, guarantee long-term preservation of pipelines in use;
6. No external sources of energy is required while work production due to the full autonomy of rigs;
7. No need for production work on dewatering at high water table.
The financial and economic aspects
- Reduction of the estimated cost of pipeline construction by reducing production time, the cost of additional manpower and heavy earth moving equipment;
- Minimize power-supply costs due to the efficiency of systems;
- No cost to restore the damaged sections of roads and railways, green spaces and objects of urban infrastructure;
- Reducing of operating costs under control and repair of pipelines in service.
Social and environmental aspects
- Conservation of the natural landscape and the ecological balance in the places of work, the exclusion of anthropogenic impacts on flora and fauna, erosion of beaches and sediment basins;
- Minimizing the adverse effect on the living conditions of people in the work area.
Let’s consider the classic situation of pipeline replacement in the city.
|Action||Using standard method of digging a trench||Using horizontal drilling method|
|Digging a trench||
Dig. Damaging roads, pavements, landscape and planting, city infrastructure (f.e. public transport stops).
|City traffic problems||Yes||No|
|Work speed||Low. Laying a 720d. pipe on 100m. distance takes 6 days.||High/ Laying a 720d. pipe on 100m. distance takes 3 days|
|Damage of existing communications||High risk. In most cases there is an occasional damage of the communications that were laid before. As a result we hold recovery costs.||Low risk|
|Allowing documentation||Big amount of formalities, have to get a lot of different permissions, bearing the costs, loss of time for departments coordination, paying penalties.||Small amount|
|Architecture violating||Yes. (f.e. old part of the city, stone pavement).||No|
|Safety of working process||Having extra charges for trench sides strengthening in order working possibility at more then 2 meters depth. In this case there is a need of additional machinery and additional technicians.||No charges|
Deep pipelaying possibility
|No||Up to 20 m|
Trenchless method – horizontal directional drilling (HDD)
|The amount of work, financial costs, time limits|
|Large amount of excavation work, involving equipment and workforce;
Long construction time.
|One drilling rig takes 3 to 6 operators team. (depends on the rig capacity).
30 %-50% reducing of financial costs.
Reducing of the construction period in 2 to 20 times.
|Costs of the accidents and their consequences;
Operating expenses for the control and maintenance.
|The risk of the accidents is minimized.
Guarantee of pipelines long-term safety. Lower operating costs.
|Environment and a man|
|Irreparable damage to nature is applied; Dependence on the period of navigation;
Violation of traffic;
Breaking of pavement;
Disruption of people's live order.
|Nature and landscape are left untouched;
No interruption of road and rail transport;
No pavement damage;
No causing discomfort.
Thus, even a standard situation gives us a significant advantage when using the HDD method. There is large number of cases when we cannot manage without this method: laying under water bodies, roads and other obstacles. In these cases, it is simply impossible to compare the economic expediency, because it is impossible to use other methods of communications’ construction.