Predicted and Observed Performance of an Anchored Retaining Wall in Granite

The results of suitability & acceptance tests carried out on tie – back ground anchors for a deep excavation in Dublin are presented. Excavation was made through firm to stiff gravelly clay and weathered granite. The excavation has been supported by 750mm diameter hard – soft secant pile wall rock – socketed into intact granite and tied – back with a single level of ground anchors at capping beam level.

Anchor test results are back – analysed to estimate the apparent free lengths of the anchors, these are compared with original design estimates. Monitored wall deflections at various stages in the excavation process are also compared with design predictions.

Measured results are discovered to be lower than design estimates. Existing design approaches are shown to be quite conservative. It is recommended that wherever possible, designers should place greater reliance on data from relevant local case histories in similar ground conditions.

• Introduction

• Local Geology

• Proposed Development

• Construction Procedure

• Design of Tie-Back Anchors

• Anchor Testing

• Experimental Results & Discussion

• Conclusions

• References