Disadvantages

Advantages

Disadvantages

No sedimentation.

Minimal ground disturbance.

No disturbance in water body or wetland.

Maintains normal water flows.

Ground disturbance of drilling and target areas.

Disposal of drilling fluids.

Fractures in the subsurface may release drilling fluids into the water body.

Potential for blowouts.

Greatly reduces the clean-up and reclamation efforts and costs.

Reduces permitting time and effort.

Largely dependent upon the subsurface conditions.

Specialized equipment and crews required.

Limits on the stress radius of the pipe to be installed.

Maintains fish passage.

Another factor in the increased popularity of HDD for municipal applications is the acceptance of HDPE pipe for water and sewer projects. During the 1970s and 1980s municipal gas utilities drove the demand for HDPE pipe. While HDPE pipe has been in use since the early 1950s, it was only during the last several years that the potable water and sewer industries were attracted to the benefits for their applications. In 1978, the American Water Works Association (AWWA) approved

Plowing Hdpe PipeHdpe Pipe Accessories
FIGURE 1-3 HDD Utility Applications

HDPE pipe for water service; at that time the maximum diameter tubing was just 3 inches. In June 1990, AWWA developed the first edition of AWWA Standard C906-90 for 4-inch through 63-inch HDPE pipe and fittings designed for water distribution. The new standard opened the way for innovative applications, and water suppliers began to realize the economic and performance advantages of HDPE.

HDD construction is more suitable for utility applications than any other trench-less procedure. The HDD equipment available today is capable of installing pipe in the sizes that the majority of water and sanitary sewer systems use. As a result, HDD is responsible for a growing percentage of public works construction. HDD equipment developed specifically for utility work was introduced in the late 1980s. Compared to today's models, they had limited capabilities. In the mid-1990s HDD equipment came into wide use, attracting the most attention for its role in telecommunications construction. Today HDD is being used on water projects using both force-main and gravity-flow sewer systems.

Several factors make directional drilling more appropriate for public works construction than in the past:

  1. Current HDD equipment can install pipe in large diameters.
  2. Directional drills are perfectly suited for installing the types of pipe used in water and sewer systems. HDD crews are experienced in the installation of fused lengths of HDPE pipe. Restrained-joint PVC pipe products are ideally suited for installation by HDD equipment; couplings quickly lock sections of pipe together, holding them firmly while pipe is pulled into place by a directional drilling unit.
  3. Today's HDD equipment can operate effectively in most soil conditions, including loose and solid rock.
  4. Directional drilling often requires less support equipment than other methods.

HDD is a viable construction alternative that has become very competitive cost-wise in areas where there is limited access and in high-traffic locations, where it eliminates most surface repairs. HDD allows engineers to accomplish work in a more environmentally friendly way. HDD also offers the same benefits for sewer projects, but the need to install pipe on grade for gravity-flow systems has made its acceptance slower. HDD contractors have successfully installed gravity-flow and force-main sewer lines with HDD equipment. New guidance electronics, developed specifically for the sewer market, makes to-grade installations easier to accomplish. HDD is not just for sewers where open-cut construction is not convenient. Many in the municipal market believe that HDD will soon be the primary method of construction and will be used even when project owners do not require it. It will be used because it is the best construction option available.

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Responses

  • Macey
    What are the disadvantages of drilling machines?
    7 years ago
  • kyran
    Is hdd accurate for 4 inch gravity sewer?
    6 years ago
  • brigitte
    What is disadvantages of drilling fluids?
    6 years ago
  • ADELGRIM
    What is the disadvantages of gyro system in Horizontal directional drilling?
    4 years ago
  • rosalinda
    What are some advantages of directional drilling?
    2 years ago
  • brhane
    What is disadvantages of horizontal boring machine?
    2 years ago
  • karin
    What is the advantage and disadvantages of directional in drilling method?
    5 months ago

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