Application of Diverse Ground Improvement Techniques for the Stabilization of Reinforced Earth Wall Approach Ramps-PPT Presentation

PPT Presentation

Pdf Summary

The presentation describes ground improvement works for two reinforced-earth-wall approach ramps, where differential settlement between piled and unpiled areas and possible collapse of soil upon wetting were key concerns. The project covered approximately 31,000 m², with ramps divided into five zones according to wall height and loading.<br /><br />The most heavily loaded areas, Zones 1 and 4, received deep soil mixing (DSM) using 2 m diameter soil-mix columns on a 2.25 m triangular grid. The design required an average unconfined compressive strength of 1.5 MPa and limited settlement to 12.5 mm under a 575 kPa working load. Lower-height Zones 2, 3 and 5 were treated with pre-boring, 900 mm vibro-replacement stone columns, and supplementary rapid impact compaction (RIC) and high-energy impact compaction (HEIC).<br /><br />In total, 2,287 DSM columns and 3,992 stone columns were installed. Verification testing showed that the DSM-treated areas settled 3–5 mm at working load and 5–8 mm at twice that load, meeting the settlement criterion. All 360 DSM compressive-strength tests achieved the required strength. Tests in Zones 2, 3 and 5 also passed project criteria; post-treatment CPT attempts encountered early refusal in the already-hard ground.<br /><br />The project demonstrates how different improvement methods were combined to suit varying ground conditions and structural demands, with testing confirming that the specified performance requirements were met.

Keywords

ground improvement

deep soil mixing

DSM columns

stone columns

differential settlement

reinforced-earth-wall

vibro-replacement

rapid impact compaction

high-energy impact compaction

soil stabilization