Earthworks on construction sites frequently create temporary and permanent slopes in both cut and fill operations. Slope failures can occur suddenly, burying workers and plant under large volumes of material. The risk increases with slope height, steep angles, poor ground conditions, water saturation, and vibration from nearby plant. Understanding the warning signs of slope instability and maintaining a safe distance from slope crests and toes are essential precautions for everyone working on earthworks projects.
Key Hazards
Slope failure burying workers and plant under tonnes of displaced material
Tension cracks at the crest warning of imminent rotational slip failure
Water saturation reducing soil shear strength and triggering sudden mudslides
Vibration from heavy plant destabilising marginally stable slopes nearby
Control Measures
Ensure all temporary slopes are designed by a geotechnical engineer for the actual ground conditions.
Monitor slopes visually at the start of every shift for tension cracks, bulging, and water seepage.
Install movement monitoring equipment on critical slopes as specified by the geotechnical engineer.
Restrict vehicle and plant movements along the crest of temporary slopes to prevent overloading.
Install drainage at the crest to divert surface water away from the slope face.
Maintain the designed slope angle and do not allow steepening from erosion or unauthorised excavation.
Keep all workers and plant clear of the toe of temporary slopes where failure debris would accumulate.
Reassess slope stability after every period of heavy rain, frost, or prolonged dry weather.
Brief all operatives on the warning signs of slope instability and the evacuation procedure.
Remember
Slope failures can occur suddenly and without warning, burying everything in their path.
Tension cracks running parallel to the crest are a critical warning sign of imminent failure.
Water is the biggest single factor in slope instability — drainage at the crest is essential.
Heavy plant near slope crests adds surcharge loading that can trigger a failure in marginal ground.
After heavy rain, slopes must be reassessed before anyone works near the toe or on the face.
If you see cracks, bulging, seepage, or hear unusual sounds from a slope, move away and report immediately.
Applicable Legislation: CDM Regulations 2015 · BS 6031 (Code of Practice for Earthworks) · Health and Safety at Work etc. Act 1974