EXC/Support Systems/TBT-EXC-033
Sheet Piling as Excavation Support
Excavations › Support Systems › Sheet Piling as Excavation Support
Toolbox Talk
Sheet Piling as Excavation Support
Sheet piles driven around the perimeter of an excavation provide robust lateral support that prevents ground collapse. They are used for deep excavations, cofferdams, and sites with high water tables where other support methods are insufficient. This talk covers the hazards of using sheet piling as excavation support and the controls required during installation, excavation, and removal.
Key Hazards
Ground collapse if sheet piles are not driven to adequate depth or spacing
Water ingress through gaps between interlocking sheet pile clutches
Workers struck by sheet pile sections during handling and driving operations
Vibration damage to adjacent structures from pile driving equipment
Control Measures
- Ensure the sheet pile wall is designed by a competent temporary works engineer for the ground conditions.
- Drive piles to the depth and embedment specified in the design before excavation proceeds below them.
- Monitor the sheet pile wall for deflection using inclinometers or survey targets at design intervals.
- Install walings, struts, or anchors at the levels and spacings specified in the temporary works design.
- Manage groundwater behind the piles using dewatering as specified to reduce hydrostatic pressure.
- Establish exclusion zones around the piling rig during all driving and extraction operations.
- Monitor vibration at adjacent structures and reduce driving energy if trigger levels are approached.
- Inspect clutch interlocks for gaps and treat any water seepage through the wall promptly.
- Do not excavate below any support level ahead of installing the next tier of walings or struts.
Remember
- Sheet pile walls must be designed by a competent temporary works engineer for the actual conditions
- Drive piles to the specified depth and embedment before excavating below them
- Monitor wall deflection at design intervals and compare readings against trigger levels
- Install walings, struts, or anchors at the levels specified before excavating to the next depth
- Do not excavate below a support level ahead of installing the next tier of walings or struts
- Monitor vibration at adjacent structures and reduce driving energy near trigger levels
Applicable Legislation: CDM Regulations 2015 · BS 5975:2019 (Temporary Works) · BS EN 1993-5 (Steel Piling) · Health and Safety at Work etc. Act 1974
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