Large-scale earthworks including embankment construction, cut-and-fill operations, and land regrading near existing buildings, bridges, and retaining walls can cause ground movement, settlement, and structural distress. Vibration from compaction plant adds further risk. This talk covers the controls needed when carrying out earthworks adjacent to existing structures on UK construction sites.
Key Hazards
Settlement damage to adjacent buildings from earthworks surcharge loading
Vibration from compaction plant causing cracking in nearby masonry structures
Slope instability from earthworks undermining the toe of existing retaining walls
Drainage disruption causing waterlogging and ground softening near structures
Control Measures
Review the structural survey and geotechnical assessment for all adjacent structures before starting.
Install settlement and tilt monitoring points on nearby buildings and review readings regularly.
Set vibration trigger levels on adjacent structures and monitor during all compaction activities.
Maintain a safe offset distance from existing foundations as specified by the design engineer.
Control surface water drainage to prevent flows undermining existing structure foundations.
Place fill in thin layers and use lighter compaction equipment near sensitive structures.
Brief the earthworks team on the proximity of structures and the monitoring trigger levels.
Notify building owners before starting earthworks near their property.
Record all monitoring data and report any exceedance to the design engineer immediately.
Remember
Install monitoring on all adjacent structures before earthworks begin nearby
Set vibration trigger levels and monitor during every compaction activity near buildings
Maintain the safe offset distance from existing foundations specified by the engineer
Use lighter compaction equipment and thinner fill layers close to sensitive structures
Report any monitoring exceedance to the design engineer immediately for assessment
Applicable Legislation: CDM 2015 · Party Wall etc. Act 1996 · BS 5228-2 (Code of Practice for Vibration) · BS 6031:2009 (Code of Practice for Earthworks)