HDD Specs Developed For Ohio DOT

By Jeff Griffin, Senior Editor | March 2013, Vol. 68 No. 3

Drilling Fluids -- Specifications require drilling fluid to be made with clean water and that additives are environmentally safe and approved for use in drilling fluids. Water and additives must be thoroughly mixed. The mixing system shall continually agitate the fluid during boring operations. Boring fluid shall be maintained at a viscosity sufficient to suspend cuttings and maintain the integrity of walls of the bore wall. Fluids must be contained and disposed of in accordance with state/federal regulations and permit conditions with no environmental risk.

Operations/Procedures/Execution
-- The 10 specifications have sections titled operations/procedures/execution which cover:

  • Site preparation and pre-construction survey;
  • Drill path survey -- the entire drill path shall be accurately surveyed with entry and exit stakes placed in the appropriate locations within the areas indicated on drawings;
  • Location of utilities -- the majority of the specs require the contractor to notify all companies with underground utilities in the work area via the state or local one-call agency to obtain utility locates and verify locations;
  • Pipe handling;
  • Pilot hole -- the pilot hole shall be drilled along the bore path as specified to tolerances for entry point location, elevation, limitations on depth, alignment, curve radius and exit point location;
  • Reaming and pull back; and
  • Testing installed pipe -- the majority of specifications require pressure and leakage testing, and five specs require hydro-testing.

Site Restoration -- Four specifications have a section titled site restoration, most requiring that following the drilling operations, the contractor shall demobilize equipment and restore the work site to original condition or better. Restoration shall include paved and unpaved surfaces, shrubbery, landscaping, trees, structures and all else encountered. Any noticeable surface defects, due to the drilling operation, shall be repaired. All excavations will be backfilled and compacted according to the project’s specifications.