![]() CTP Laying of optical fiber in existing belowground infrastructures.(Read more in " 7 Types of Trenchless Rehabilitation Methods and How They Are Used. However it is essential for every contractor undertaking an HDD projectto be familiar with some key aspects as mentioned above to complete a trenchless project.Įmploying a knowledgeable contractor and engineer who can follow the design parameters to the dot is essential to ensure successful completion of any project. Conventional methods of laying pipelines are slowly becoming obsolete thanks to trenchless technology’s no dig methods that reduce traffic congestion, and environmental impact on wetlands, estuaries, rivers, etc. HDD is fast becoming an essential tool in the contractor’s tool box. First aid kit should always be kept handy for minor accidents that can be treated on site. Not only will it provide a safe working environment, it keeps away the worry of work place accidents. All safety procedures with regards to handling of machinery, equipment, chemicals, personal safety etc. However it should be the first undertaking at the beginning of any project. Safety procedures are usually mentioned at the end of an article to keep it fresh in the mind of the reader. should be recorded at constant intervals. Other factors like exit and entry, rate of mud flow, circulation of drilling fluid, axial tension force, etc. The pipe should be handled with care by providing proper support to minimize bending. To ensure proper pulling, all procedures for fusion welding and inspection should be followed. Pulling the pipe back through the pipe can be challenging because the pipe needs to be pulled in one segment without breakage. Uneven distribution can cause failure of borehole or problems during pipe pullback. It is essential to have the correct viscosity of the drilling fluid that will allow the cuttings to be suspended, and must be constantly monitored to ensure that the pumps are not overworked and that the fluid is evenly distributed throughout the borehole. It also acts as a cleansing and stabilizing agent that keeps the hole from collapsing and reduces torque while drilling. Viscosity and Distribution of Drilling Fluidĭrilling fluid consists of a mixture of bentonite and water that is used to lubricate the hole during drilling and reaming. Usually another reamer of the same size is passed back again to remove remaining debris and to compact the wall of the borehole. Once the pipe is installed, it will have to withstand vertical earth pressure without immediate support from the surrounding soil. This margin or oversize is about 1.2 to 1.5 times the pipe diameter and depends on factors like soil stability, hydrostatic pressure, depth of drilling, etc. Once the pilot hole is drilled, it needs to be expanded to the appropriate size with sufficient margin to allow the pipe to be pulled in easily. The entry and exit points should be chosen with care such that the maximum radius of curvature is attained in the direction of drilling. Since the pipe has to be pulled through the hole, too much curvature or too many curves can increase the tensile strength, thus reducing the pipes resistance to collapse. Since curvature induces bending stress, it should be kept to a minimum so that the pullback load is reduced. While designing the drill path, one of the most important factors to consider is the radius of curvature. Free Download: An In-Depth Look At the Horizontal Directional Drilling Process On the exit point, sufficient space should be provided so that joining and fusing pipes can be done in a continuous string. For example: For a Maxi HDD project requiring a 1000-feet crossing may also require a space of (100x150) feet. A project involving larger pipes will require greater quantity of drilling fluid, larger pumps, mud storage equipment, etc. ![]() While it is true that HDD takes up lesser working space, sufficient space should be provided depending upon the size of the project undertaken. ![]() All buried structures within 10 to 25-feet (depending on mini or maxi HDD application) of the route, should be located to avoid cross boring. The entry and exit points should not be at a difference of elevation of more than 50-feet and should be located within eye range clear of above ground obstructions. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |