TWK/General/TBT-TWK-016

Temporary Ground Anchors

Temporary Works › General › Temporary Ground Anchors

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Temporary ground anchors provide tensioned support to retaining walls, sheet piles, and excavation support systems.
Anchors are drilled into the ground behind the retaining structure and stressed using hydraulic jacking equipment.
Anchor installation involves drilling, grouting, curing, stressing, and locking off under significant tension forces.
A snapped anchor tendon or failed lock-off device can release stored energy violently, causing fatal injuries.
Ground anchors are temporary works requiring design, installation supervision, and testing by competent persons.
Proof testing and acceptance testing verify each anchor achieves its design load before the wall is loaded.
Drilling for anchors creates noise, vibration, and spoil that must be managed with environmental controls.
Anchor heads and stressing equipment create exclusion zone requirements during tensioning operations.
BS 8081 and BS EN 1537 set the UK standards for the design, installation, and testing of ground anchors.
Temporary anchors must be de-stressed and removed or made safe when the permanent works take over.

Prevent retaining wall failure	Ground anchors hold retaining walls in place — anchor failure can cause wall collapse and excavation flooding.
Stored energy hazard	Tensioned anchors store enormous energy — sudden release during stressing or failure can be fatal.
Temporary works duty	CDM 2015 requires ground anchors to be designed, installed, tested, and supervised as formal temporary works.

Don't

Ensure ground anchor design is approved by the temporary works coordinator before installation
Establish exclusion zones behind anchor heads during all stressing and testing operations
Use calibrated hydraulic jacking equipment and monitor pressures against the test schedule
Carry out proof testing and acceptance testing on every anchor as specified in the design
Record all installation data including drill depth, grout volumes, and test results for each anchor
Brief all workers on the stored energy hazard and exclusion zones before stressing begins
Inspect anchor heads, wedges, and bearing plates regularly for signs of movement or corrosion
Ensure drilling operatives wear RPE, hearing protection, and eye protection during installation
Monitor the retaining wall for movement during and after anchor stressing operations
De-stress and remove temporary anchors safely when the permanent structure is complete

DON'T stand behind or in line with anchor heads during stressing or load testing operations
DON'T stress anchors beyond the design load without the engineer's written authorisation
DON'T skip proof testing — every anchor must be verified before accepting it into service
DON'T use uncalibrated jacking equipment for anchor stressing or testing operations
DON'T leave temporary anchors in place without a de-stressing plan when the works are complete
DON'T drill anchor holes without confirming the absence of buried services in the drilling path
DON'T ignore signs of anchor head movement, cracking, or bearing plate deformation
DON'T allow grout to enter watercourses or drainage systems during anchor installation
DON'T modify the anchor stressing sequence without approval from the temporary works designer
DON'T treat ground anchor installation as a routine drilling task — it requires specialist competency

See also: Temporary Works Awareness | Sheet Piling Installation

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