Once the initial HDD Profile has been developed, the selected pipeline material can then be verified for construction. The calculation assesses all forces applied to the product pipe during installation, determining if pipe will be de-formed or de-rated during the process, and to what degree.

The Installation Calculation is primarily based on product pipe specification and HDD Profile. It also includes adjustments for ballasting, friction coefficients, drilling fluid properties, direction of installation, drilling equipment, and fabrication or corrosion allowances, ensuring that the specific trenchless construction methodology and conditions are taken into account.

The installation calculation is performed utilising the above input data and applying these to various peak standards for HDPE and steel pipelines, including the following:

• Australian standards
• Pipeline Research Council International standards
• Det Norske Veritas standards
• American Society for Testing and Materials standards.

The calculations provide an overview of assumptions and expected loads, providing clients with the full picture of force analysis. The calculation provides valuable information on product pipe suitability and assists the construction team to potentially identify downhole issues before they become irreversible. Should the calculations have an unacceptable factor of safety, revisions to the initial design or the product pipe selection can be made and the calculation iterated until an acceptable and constructible solution is developed.

From here, additional complementary products, such as Anchor Block calculation and design, torque and drag calculations, pulling head design, Drilling Fluid Plan, and Site Layouts can be used to further determine and document installation requirements.

Site Layouts are a vital planning and constructability tool that depict the plant and equipment positioning for the completion of trenchless works. This includes the entry and exit layouts, breakover alignments, indicative noise levels, and pipe string preparation and welding areas.

Site Layouts combine site conditions from several sources. They are initially drafted to include the following:

• Trenchless HDD Profile and alignment detail
• Existing property and site boundaries
• Environmental impact areas
• Surveyed features, including trees, light poles, road edges, etcetera
• Pipeline easements
• Surveyed existing services
• High quality aerial imagery.

Drilling fluid is a vital component of every HDD Project. During drilling operations, a viscous fluid is pumped through the drill string, out the downhole tooling and into the borehole annulus. The drilling fluid is used to excavate, stabilise, lubricate and carry cuttings out of the bore hole. The Drilling Fluid Plan is a planning and operational tool that provides concise guidelines to maintain target rheological properties and estimate required waste/resources.

Detailed planning and assessment are required to effectively develop the drilling fluid plan. In order to provide recommendations to achieve optimum fluid, operations, and borehole performance, an evaluation of drilling methodology including product pipe sizing, downhole tooling, surface equipment and pumping variables is undertaken.

A Future-Proof Solutions Drilling Fluid Plan is tailored to the variables of your project and provides a holistic view of recommended drilling fluid requirements, including:

Pipe handling is an essential but high-risk activity during the construction of any trenched or trenchless pipeline. Breakovers – also known as overbends – are necessary when a long string of pipe is required to be moved or lifted into an arch in order to be installed.

Breakovers have the potential to introduce a variety of additional quality and construction risks which must be mitigated to ensure that the pipeline is installed without undue damage to the pipe or risks to constructability. By adequately planning and designing a breakover, the balance between material elasticity, stiffness, and strength can be managed to avoid overstressing, kinking or damaging product pipe and its coating as it is lifted, pulled and installed into the drilled hole.

To establish a Future-Proof Solutions Breakover Plan, initial breakover designs are created, taking into account pipe specifications, construction methodology and profile and alignment factors, such as borehole exit angle, minimum pipe bend radius, available stringing area and above ground obstacles. A comprehensive, site-ready Breakover Plan drawing is then finalised, establishing the pipe and equipment positioning while complying with known engineering, methodology and site requirements.

Plotted over aerial photographs and continuing from the HDD Profile drawing, the Breakover Plan sets out section-by-section information including:

• Ground elevation
• Pipe elevation
• Lift height
• Chainage
• Bend details
• Pipe supports, plant, and equipment.

Trenchless project methodologies can be difficult to communicate both on site and to project stakeholders, due to the majority of activities occurring underground. To solve this problem, our Engineering Team has developed the Execution Summary: a logical, straightforward pictorial illustration of each step of the trenchless project methodology from start to finish.

To develop the Execution Summary, our Team of HDD Specialists reviews relevant project inputs, such as the HDD Profile, Site Layouts, environmental constraints, proposed equipment, and geotechnical conditions.

These inputs and related project risks are then assessed, streamlined, and optimised to determine the best suited project methodology. A concise series of drawings of each step of the project in chronological order is produced, detailing the processes and equipment to be utilised to execute each stage of the trenchless methodology. Depending on the project, these may include:

• Surface casing (also known as conductor casing) installation via hammer or wash over methods
• Establishment of entry and exit sites
• Pilot drilling and borehole enlarging reaming passes
• Supplementary passes, including drill pipe tripping and borehole conditioning
• Marine interface operations
• Product pipe welding
• Product pipe installation
• Testing, pigging, and gauging.

The HDD anchor is used to secure the rig in place on trenchless projects and provide resistance to forces during drilling, reaming, and pullback. HDD anchor design is crucial in preventing overturn, sliding, or anchor failure, and must address various factors to be suitable for project operations. We’ve designed our HDD Anchor product specifically to ensure all information is considered and the anchor is designed correctly, for maximum project success.

To complete HDD anchor design, we gather information including the geotechnical parameters of surrounding soil; HDD applied loads from thrust and pull; weight of rig and other plant and equipment; proposed anchor dimensions and materials; and Site Layout. Detailed analysis is then completed as such:

• Safety factors from AS5100.3 are applied to increase applied loads and reduce geotechnical strength for worst case analysis
• Passive resistance forces are calculated to determine how much effective earth pressure the soil can exert on the anchor
• Applicable failure criteria are analysed using all forces to determine if the anchor will fail under ultimate bearing, sliding or overturning mechanisms
• Diagrams of failure mechanisms are produced.

The HDD Anchor product is then finalised to include:

• Calculations of forces applied by the HDD rig to the anchor, providing a factor of safety for each failure mechanism, including reduction factors
• Assessment of whether soil properties are sufficient to withstand loads, and whether the anchor design is appropriate for the conditions
• Recommendations for anchor suitability
• Anchor drawings, including isometric 3D and 2D views
• Material take off for the proposed anchor, summarising required materials for construction.

Using the right tools for the job is vital in HDD, but particularly in relation to downhole tooling, or bottom hole assemblies (BHAs). Selection of fit-for-purpose cutting tools, stabilisers, subs, hydraulic motors, and other threaded tools is crucial in ensuring each pass achieves its intended purpose safely, effectively, and economically.

We’ve designed our BHA Summary product to streamline the process of planning and assessing downhole tooling, as well as selecting and clearly communicating the best tooling for each trenchless engineering project. To do so, our HDD specialist engineers first review the project parameters, planned methodology and expected loading conditions, and consider aspects such as:

• Geotechnical conditions
• Crossing lengths and radii
• Required borehole size, pass sizes, and methodology
• Project equipment, such as rigs, pumps, and available tooling
• Torque, tensile, compression, and bending loads.

One of the main difficulties when drilling a prescribed HDD bore arises from controlling the slender downhole tooling during its interaction with the layered stratum.  Poor, varied or unexpected ground conditions can cause the drill bit to stray off the design, increasing risk potential which can result in unplanned, costly outcomes for the contractor.  Magnetic, gravity and gyroscopic sensors are available to assist steering for HDD construction projects.

A ‘walkover’ system is a cost-effective methodology for monitoring both the depth and direction of a horizontal drill; providing real-time feedback to the driller to enable constant adjustment to the drilling direction.  Future-Proof Solutions’ Drill Plan has been developed with this methodology in mind.

This Plan takes into account the BHA tooling, sonde position and breaks the HDD design into a rod-by-rod plan, providing navigational measurements specific to the HDD bore including:

• Rod number
• 2D chainage
• Measured depth
• Depth of cover
• Inclination
• Surface level
• Elevation relative to datum

HDD and other trenchless methods are commonly used to install pipelines under roads, railways, and other sensitive areas. The low-impact nature of trenchless installation is one of its greatest strengths – allowing vital pipelines to be placed with minimal disturbance and interruption at surface level.

However, many types of infrastructure are particularly sensitive to surface subsidence – also known as “settlement” – and detailed calculations must be completed to predict the long-term impact of settlement on the ground surface above and adjacent to the installed pipeline. In these situations, Future-Proof Solutions’ Settlement Analysis product can help.

To complete a Settlement Analysis, our Engineering Team reviews project-specific data, such as geotechnical information, pipeline depth of cover, pipe leave state, and product pipe and borehole sizes. Then, after assessing the geotechnical layers for points of interest, settlement calculations are performed based on Gaussian distribution curves.