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METHOD 04 · BURIED UTILITIES

Ground-penetrating radar for detecting and mapping buried utilities

Know what is under the ground, and at what depth, before digging: pipes, cables, ducts, including plastic networks.

THE METHOD

How it works

We combine two complementary techniques. GPR sends waves into the ground and detects any object that differs from the surrounding soil, whether metal, concrete or plastic. Electromagnetic detection picks up the signal of a live cable or a metallic pipe, or the one we inject into a conductive network.

Each utility found is positioned to the centimetre by GNSS, then plotted on a plan with its estimated depth and confidence level. The two techniques cross-check: a utility seen by both is confirmed, a utility seen by only one is flagged as such.

WHAT IT IS FOR

The problems the method solves

  • Avoid damage to utilities during earthworks, foundations or road works.
  • Find plastic utilities (PVC, HDPE) that conventional electromagnetic detectors do not see.
  • Update old or non-existent plans, particularly in industrial areas or urban extensions.
  • Prepare a laying or diversion site by knowing the interferences.
  • Have a georeferenced inventory of the subsurface for a utility or site manager.
WHAT YOU RECEIVE

The results we deliver

Georeferenced plan

Plan of the detected utilities, with their estimated depth, in CAD (DXF) and GIS (SHP) format to integrate into your tools.

Confidence level

For each route, the detection method used and the level of certainty, so you can decide with full knowledge.

Report and 3D option

Intervention report and, optionally, a georeferenced 3D model of the subsurface (BIM).

Reference practice: standard NF S70-003 (class A targeted); ASTM D6432; ASCE 38.

HOW TO USE IT

What this changes for your decisions

  • Safer works: you dig knowing the utilities, and test pits are limited to points of doubt.
  • Fewer work stoppages, service cuts and repairs.
  • Reliable plans to plan future extensions.
  • A utility database that is updated campaign after campaign.
OUR EQUIPMENT

The equipment selected

PROCEQ (SCREENING EAGLE) · GPR FOR BURIED UTILITIES

GS8000 Pro

Stepped-frequency continuous-wave (SFCW) GPR designed for detecting and mapping utilities.

At a glance

  • Frequency range from 40 to 3,440 MHz
  • Smallest detectable target: 1 cm (according to the manufacturer)
  • Real-time GNSS positioning: typical accuracy of 1 to 5 cm
  • Pro version: all-terrain wheels and underside protection

Why this choice

The wide bandwidth provides both resolution near the surface (the first 1 to 1.5 m) and good penetration. It can detect plastic and non-metallic utilities, which electromagnetic detection alone does not pick up, when the contrast with the soil is sufficient.

VIVAX-METROTECH · ELECTROMAGNETIC DETECTION

vLoc3-Pro and 10 W transmitter

Locator for metallic utilities and cables, in active mode (with transmitter) and passive mode.

At a glance

  • Active mode: the signal is injected into a conductive network to follow its route
  • Passive mode: detection of live cables (50 Hz)

Why this choice

It is very effective on conductors and complements GPR: the two techniques cross-check, which reduces the risk of a missed utility.

EMLID · GNSS RTK

Emlid Reach RS3

Precision GNSS receiver for positioning the routes.

At a glance

  • Centimetre-level positioning with RTK

Why this choice

It makes it possible to deliver a plan usable directly in your tools, with routes that can be marked out in the field.

Equipment selected for our first campaigns, being acquired, rented or provided through partnerships depending on the instrument; availability is confirmed when the order is placed. Characteristics as stated in the manufacturers' data sheets; they depend on configuration and terrain.

LIMITS

What the method does not do

  • Very clayey, wet or salty soils attenuate the GPR signal and reduce the usable depth.
  • Electromagnetic detection only sees conductive utilities or those accessible for injecting a signal.
  • A very deep or very small utility may remain invisible: the report states the confidence level of each route.

A corridor or structure to inspect? Let's talk about your need.

Write to us

Other methods

Ground-penetrating radar for roadsGround-penetrating radar for railwaysGround-penetrating radar for airport pavement inspectionStructural inspection with ground-penetrating radar and ultrasonic tomography