Introduction to Ground Disturbance

What is ground disturbance? The term “ground disturbance” has been adopted by industry to replace the term “excavation”. This is because there are many activities, other than excavation, that disturb […]

What is ground disturbance?

The term “ground disturbance” has been adopted by industry to replace the term “excavation”. This is because there are many activities, other than excavation, that disturb the ground.

Ground disturbance requires a systematic approach that should include: planning, verification, execution of procedures and inspection.

Ground disturbance is any work, operation or activity, on or under the existing surface, resulting in a disturbance or displacement of the soil, but not if the disturbance or displacement is a result only of:

  • Routine, minor road maintenance.
  • Agricultural cultivation to a depth of less than 45 cm below the ground surface over a pipeline.
  • Hand digging to a depth of no more than 30 cm below the ground surface.

Ground disturbance is one of the most hazardous construction operations. Ground disturbances are often big projects with heavy equipment but they can also be smaller projects like digging foundations, repairing utility pipes, or drilling post holes.

Everyone who is involved in ground disturbance needs the training to know about the hazards and how to work safely. It is also important to know that ground disturbance regulations are not the same in all provinces.

Generally speaking, excavation is a hole in the ground as the result of removing material. A trench is an excavation in which the depth exceeds (is bigger than) the width.

Digging is actually the combination of two processes, the first being the breaking or cutting of the surface, and the second being the removal and relocation of the material found there. This may be accomplished in a single motion, with the digging implement being used to break the surface.

Drilling is a cutting process that uses a drill bit to cut a hole of circular cross-section in solid materials. The drill bit is usually a rotary cutting tool, often multi-point. In rock drilling, the hole is usually not made through a circular cutting motion, though the bit is usually rotated. Instead, the hole is usually made by hammering a drill bit into the hole with quickly repeated short movements.

Other types of ground disturbances are:

  • Plowing
  • Quarrying
  • Scraping
  • Boring
  • Ditching
  • Dredging
  • Grading
  • Blasting

What are Ground Disturbance Hazards?

There are different hazards that workers can face during the ground disturbance, those are:

  • Cave-ins

The risk of cave-ins is one of the most serious hazards of ground disturbance. An unstable trench or excavation can collapse, crushing or suffocating trapped workers. A worker buried under one metre of soil has so much pressure on the chest that the lungs can’t breathe in and out. Suffocation occurs within approximately three minutes. Even if the worker is rescued quickly, the heavyweight of the soil is likely to cause serious injuries to bones, muscles, and internal organs. This is why safety measures in order to avoid cave-ins are extremely important.

  • Trench Stability

Many factors can affect the stability of soil:

  • Bad weather conditions can make the trench less stable.
  • Moving machinery, pile driving, and blasting, all causing vibrations in the soil that can destabilize excavations.
  • Adjacent buildings and other structures can put pressure on the walls of excavations.   
  • Some soil types are more stable than others and they can vary greatly from the top of a trench to the bottom.
  • Must be placed a safe distance from the edge of the trench so they don’t fall into the trench and don’t put too much pressure on the soil near the edge of the trench
  • Depth, Previous Ground Disturbance, Failure of Protective Systems.
  • Hazardous Atmospheres

Atmospheric hazards can develop in partially enclosed spaces like trenches and other excavations. In fact, some types of excavations are considered confined spaces and have many of the same hazards:

  • Engine exhaust from vehicles and equipment as well as chemicals and decomposing materials in landfills can be toxic.
    • Trenches can have too little oxygen (oxygen-deficient) or too much oxygen (oxygen-enriched).
    • Propane from portable heaters can accumulate in trenches. Decaying sewage releases methane and other hazardous gases.

The only way to know if there are atmospheric hazards is to test the air before workers enter and to continue to monitor the air during the project. Workers can enter the space if tests show the air quality is safe. Otherwise, workers can’t go in until the area has been ventilated and tests show the air is safe to breathe. The air should be monitored the entire time workers are working there.

  • Other Hazards. Cave-ins and hazardous atmospheres aren’t the only hazards of ground disturbance. Workers also get injured or killed from falling into excavations or falling when they are climbing in or out. They are struck by moving vehicles and equipment, or by materials that fall on them. Workers face fire, explosions, electric shocks, and flooding. They can also hurt their backs, arms, and legs from lifting and carry heavy piping and other materials and equipment.

Ground Disturbance Utility color codes

All pipelines and utilities in the work area and the surrounding area must be marked to show both location and alignment. Called locate marks, these temporary markings can be flags, stakes, or paint. Ground disturbance cannot begin until all buried facilities are located and marked.

White: Pre-marking of the outer limits of the proposed excavation or marking the centerline and width of proposed linear installations of buried facilities.

Pink: Temporary Survey Markings.

Red: Electric power lines, cables or conduit, and lighting cables.

Yellow: Gas, oil, steam, petroleum, or gaseous materials.

Orange: Communication, alarm or signal lines, cables or conduits, and fiber.

Blue: Potable water.

Purple: Slurry, irrigation and reclaimed water.

Green: Sewers, drainage facilities or other drain lines.

Ground disturbance course levels

The Ground Disturbance Level 1 Course is a shorter awareness program that is assessed to the ABCGA 101 Ground Disturbance Standard.  Appropriate for workers that are directly supervised by a Supervisor with Level 2 certification.

eSafetyFirst Ground Disturbance program has been developed in accordance with provincial legislation as safety training for workplaces across Canada. This course consists of 3 modules and tests. Once you pass all the tests, you may print your certificate of completion (wallet & wall-sized). Training may be paused or resumed at any time, is fully narrated, and includes interactive exercises to ensure understanding of course content.

The Ground Disturbance Advanced Level 2 training course has been designed for those with an occupational requirement to be trained to safely undertake work activities that involve ground disturbance and is also intended for personnel who are required to manage, plan and supervise ground disturbance operations.

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