Rehabilitation of distressed retaining walls using soil nails Available to Purchase

The paper presents a case example of the rehabilitation of distressed cantilever retaining walls that were constructed for a road approach embankment. The retaining walls showed clear signs of distress immediately after completion and hence the road embankment was not opened for traffic. These distresses, in the form of translations, settlement of the pavement at the top and rotation of the retaining walls were observed in the field. Extensive geotechnical investigation and field measurements of distress were collected. In the present study, retaining wall sections with grouted nails as rehabilitation measures were analysed using conventional methods and finite-element analyses. The proposed rehabilitation of the retaining walls involved two types of soil nailing systems. The first system consisted of positioning nails at appropriate locations and each wall being treated as a separate entity. The second system consisted of joining the two back-to-back retaining walls using nailing across the entire width of the embankment. From the results of the finite-element analyses, it was observed that the second system of rehabilitation was likely to lead to less deformations and higher factors of safety in comparison with the first system and hence this system was considered for implementation in the field. The improved response is attributed to the counteracting effects offered by the back-to-back retaining systems. It emerges from the study that back-to-back reinforced retaining walls are likely to be more economical and stable in comparison with individual retaining walls for the design of approach embankments.