Horizontal directional drilling continues to be in demand as the utility industry expands in cities and residential areas. Above ground obstacles such as buildings, houses, and roads make it more challenging to install cables and conduits underground. Fortunately, directional drill rigs are capable of installing these pipes without causing much destruction. The process is also relatively quicker than conventional trenching and rehabilitating the project site is even faster.
But despite the success of most of the HDD projects undertaken by directional drilling companies, there are still four significant challenges to consider to ensure that the project commences smoothly and results in less expense for both the contractor and project managers.
Feasibility of HDD is affected by soil type and density
Not all soil types are compatible with HDD. If the soil is mostly gravel, engineers need to employ mitigation measures or adjust the design; otherwise, HDD will be infeasible for the soil condition. It is only possible to work with gravelly soil when the gravel is mostly concentrated near the surface. But if the entire subsurface is filled with gravel, HDD is not a feasible option, and the engineer will have to use conventional trenching methods instead.
Understanding soil conditions is, therefore, one of the most crucial steps to planning and studying the suitability of the trenchless method of laying pipes and conduits.
Forces and stresses that impact the operation
Installation forces such as the pullback force and other physical pressures affect the safety of pipeline installation. It is essential to minimise these stresses so that the pipes are handled within the limits that the material can tolerate. Every pipe used for HDD, considering the material, length and diameter can only bend to a certain extent before it breaks. The planning stages should carefully consider these factors to prevent causing undue stress to the material, especially when there are curves required in the installation path.
Changing orders can be costly
There are times when despite adequate planning, there may be unexpected situations that arise as the project commences. Some examples include rock formations underground, groundwater contamination, and an existing network of pipes. Changing the HDD plan and strategy will be costly for the contractor and project manager. To avoid these concerns, an extensive study needs to be conducted before the project begins. In addition to studying the geotechnical composition of the soil, planning engineers also need to look into all the surrounding conditions which may impact the project.
Observing the field improves results and helps in the event of disputes and claims
During construction, it is crucial for the contractor to employ heightened observation methods. For example, there needs to be detailed documentation which will not only ensure the success of the undertaking but also provide the information needed to counter possible disputes. The contractor also needs to provide daily reports to the project manager which will be valuable in the event of changes in the plan or if there are claims filed by parties impacted by the project.
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