The installation of submarine pipelines and cables can have negative effects on the marine environment. With the development of the offshore natural gas and wind industry, the demand for the construction of transfer pipeline and cables has also increased. HDD is a technique used to drill a subsea tunnel or under other designated area with the goal to pull a pipe or other facility through the drilled underground tunnel. This article presents the horizontal directional drilling (HDD) as one of the most suitable technique used to reduce the impact on the environment during the submarine pipe and cable installation process, especially in the coastal area and shallow waters.
The loss of the drilling fluid used in the drilling phase has been determined, depending on the type of soil and the related fraction as well as the possibility of treating the drilling fluid used to construct the drilling. The analyzed area included a section of the route of the strategic gas pipeline, realized in June–July 2017 in an area of lowland ash and alder forest 91E0-3, a probable breeding site of the Bluethroat for a detailed description and common frog. Drilling fluid is an element of the horizontal directional drilling technology (HDD). The loss of drilling fluid in valuable natural areas during the construction stage of the gas pipeline has been analyzed. The analyses concern the drilling stage as a low-waste technology, indicating the use and management of bentonite drilling fluid in a closed circulation cycle in the area of Pęciszów, poviat Trzebnica (Poland). The study discusses the issue of introducing drilling fluid (bentonite) into the environment during the construction of linear underground investments, considering the example of the construction of the high-pressure gas pipeline, Czeszów-Kiełczów DN1000, which involved the use of the Horizontal Directional Drilling (HDD) method. The cost analysis indicated that HDD is about 12.5% more expensive than open cut. The paper attempts to compare the cost of HDD and open cut for the installation of 1000m long of 30cm in diameter waterlines underneath the busy streets of Nairobi, Kenya a few years after the introduction of HDD to Kenya. Usually the above-cited difficulties stifle the introduction of trenchless technology to these areas. The risks are usually high on the first job and the experience with the new technology is low, which also increases the project mark up and cost. Usually the engineer resorts to trenchless technology only in most difficult situations when open cut cannot be employed and tries to limit the length of the trenchless part only to the difficult portions as a result, the cost per linear meter increases significantly.
Usually the contractor who is involved in the first trenchless project in the country tries to amortize the cost of the trenchless system through this project. This environment makes the need for trenchless technology paramount. Consequently, open cut causes significant disturbance for lengthy period of time to residents and business. The traditional open method in these countries relies more on labor force than equipment. The streets are very congested with pedestrian and vehicular traffic. The urban areas in developing countries (including Nairobi) attract immigrants from the surrounding rural areas creating very densely populated and congested areas. This study attempts to investigate the cost of Horizontal Directional Drilling (HDD) and open-cut construction methods for the installation of pressure waterlines in Nairobi, Kenya.
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