Horizontal Directional Drilling is no new term when it comes to pipe installation for sewage conveyance or water distribution. It has become a more favorable alternative in urban settings where pipes traverse essential public utilities or cross obstacles like roads and rivers. Directional boring primarily involves three critical phases. During the first phase, the contractor drills a pilot hole along a specific path from one point to another. The second involves enlarging the bore to a diameter that allows pipe installation, and the final phase requires pulling the pipe into the hole to create a continuous segment of pipe underground. The entire process can be tedious for the underground boring services contractors when you have not performed these four preliminary steps:
1. Conduct Feasibility Study on the Type of Soil and Density
The type of soil dramatically affects the directional drilling process and the pipeline installation. This is because the ground conditions present different challenges during the drilling process. Unstable soil conditions, for example, make it difficult to maintain stability for extended periods. The risk of collapse increases as the boring diameter for pipe installation increases. Gravel soils, for example, require the use of exclusive design and construction mitigation measures, or the entire HDD installation procedure becomes infeasible. This is because the soil allows liquids to flow through the particles. Fine soils like shales and clays, on the other hand, prevent water from flowing. However, they are reactive to water, which affects the drilling fluids contractors can use. If the soil is located within a small area, it’s easy to employ several mitigation techniques, but if it spreads an entire subsurface, underground boring might not be viable. Here are examples of different soil types and the risks they present during an HDD project:
- Fine sand soil: Can cause collapsing and clogging of the hole
- Fine ground soil: Joins and clogs occasionally
- Rocky soil: Rapid wear and tear of pipes and drilling tools
- Sand and pure gravel: Instability and partial/total mud loss
Conducting such a feasibility assessment prior to engaging directional boring contractors saves you time and money. Designing a unique HDD profile and implementing mitigation techniques can’t resolve problems associated with the soil type, rather presenting a feasibility and design study beforehand does. It helps the underground boring services contractors understand the impact the site’s soil type will have on the HDD installation process and determine a suitable pipeline installation method.
2. Provide a Pre-Construction HDD Design Study
Trenchless drilling for pipe installation projects experience many unanticipated changes. Having a pre-construction HDD design study minimizes such eventualities and acts as a basis for drafting bidding documents for more consistent bid outcomes. For example, if the groundwater, subsurface soil, and utility conditions are known before engaging underground boring services contractors, it makes it easy to attract a potential company. This is because they already know what to expect and mitigation techniques to employ. Again it’s difficult for the contractor to claim changed conditions as the basis for increasing the bid price as all such information was available before signing the contract.
3. Field Observation
It would help if you conducted a field assessment prior to engaging an underground boring services company. Such an assessment ensures the contractors follow the outlined specifications while increasing the probability of successful HDD installation. Additionally, the field survey allows you to prepare documentation that would act as a basis for reference in the event of a dispute.
4. Familiarize with Installation Forces
Understanding pipe installation limitations and operational requirements is critical to planning and enhancing the safety of your pipeline. Generally, Texas horizontal directional drilling involves pipe pulling, which exerts tremendous pressure on the pipe material and can cause cracking. Therefore, it’s imperative to use pipe materials than can hold up to the rigors of HDD installation. Pipes made of steel, ductile iron, medium, and high-density Polyethylene, as well as Polyvinylchloride, are the most suitable. They can be welded, fused, or joined mechanically to facilitate pulling. Also, inspect the drill rig size and the pull loads as they help minimize the excess strain on the pipe.
