Subsurface Utility Engineering (SUE) is a nondestructive method of detecting underground utilities. It includes designating the horizontal and vertical location of the utilities, land surveying, locating, data reduction, and presentation of the information utilizing CaiCE software and Microstation.

Subsurface Utility Engineering is branch of engineering practice that involves managing certain risks associated with utility mapping at appropriate quality levels, utility coordination, utility relocation design and coordination, utility condition assessment, communication of utility data to concerned parties, utility relocation cost estimates, implementation of utility accommodation policies and utility design. Cost savings on typical projects using Quality Level A and B may range from 10% to 15% (compared with costs from a project using Level C and D data). Each ascending level described below typically includes the subordinate levels.

Information derived from existing records and oral recollection.

Information obtained by surveying and plotting visible above-ground utility features and by using professional judgment in correlating this information to quality level D information.

Information obtained through the application of appropriate surface geophysical methods to determine the existence and approximate horizontal position of subsurface utilities. Quality Level B information should be reproducible by surface geophysics at any point of their depiction. This information is surveyed to applicable tolerances defined by the project and reduced into documents. United Consulting typically employs a level of accuracy for Quality Level B of approximately ± 12 inches on both the horizontal and vertical axis.

Precise horizontal and vertical location of utilities obtained by the actual exposure (or verification of previously exposed and surveyed utilities) and subsequent measurement of subsurface utilities, usually at a specific point. Minimally intrusive excavation equipment is typically used to minimize the potential for utility damage. A precise horizontal and vertical location, as well as other utility attributes, is shown on plan documents. Accuracy is typically set to 0.5 inches vertical and to applicable horizontal survey and mapping accuracy as defined or expected by the project owner.

United Consulting performs both Level B and Level A SUE services. During a Level B investigation the horizontal and vertical location of underground utilities are indicated using surface geophysical techniques such as Ground Penetrating Radar (GPR), electromagnetic, magnetic or other energy fields. Electromagnetic methods include the following: pipe and cable locators (inductive, conductive, active, and passive modes), terrain conductivity, ground penetrating radar, ground resistivity techniques, optical methods, and computer-driven algorithms coupled with data collection techniques. This method usually provides adequate, acceptable utility location data. However, if problems are encountered during the Level B investigation a Level A, vacuum exploration can be performed. A Level A investigation involves locating the precise horizontal and vertical positions of utilities by excavating a test hole to expose the utility. A vacuum excavation method is then employed to minimize the possibility of damage to a utility line.

Background

United Consulting has in-house capabilities to perform subsurface studies by the ground penetrating radar technique. We utilize a GSSI SIR-2 system and the latest software technology to locate metallic and nonmetallic underground objects. Our site studies provide accurate focal depths, location and geometry of buried objects.Applicability Using traditional methods for mapping and detecting subsurface features can be time consuming and costly. The ground penetrating radar technique is quick, easy, accurate and cost effective. Information, which was formally difficult to obtain, can now be acquired rapidly through this non-destructive technique.

Applicability

Using traditional methods for mapping and detecting subsurface features can be time consuming and costly. The ground penetrating radar technique is quick, easy, accurate and cost effective. Information, which was formally difficult to obtain, can now be acquired rapidly through this non-destructive technique.

Procedures

United Consulting performs the ground penetrating radar survey using state-of-the-art GSSI SIR-2 system and software support. During each study, data can be displayed in real-time or a color display stored on an internal hard drive or can be printed on a thermal plotter for the spot answers. A variety of different antennas operating on varying frequencies are utilized to perform investigating ranging in depth from 6 inches to 120 feet. United Consulting’s ground penetrating radar services provide subsurface profiling and location for:

  • Buried drums, trenches and pipes
  • Boundaries of abandoned landfills
  • Detects bedrock, buried boulders and soil profiles
  • Detects water table
  • Locates rebars, conduits and voids in concrete
  • Maps contamination plumes
  • Detection of voids in dams
  • Sedimentation studies
  • Profiles: tower and building
  • Renovations
  • Foundations
  • Examine damaged foundations