Rigid inclusions performance as ground improvement for lacustrine clays

Abstract

The Bogotá urban railway system involves constructing a rail maintenance yard covering 33 ha near the Bogotá River. It requires the construction of a 4.1 m embankment to overcome flood risks. Approximately 57,000 rigid inclusions (RI) were installed because of poor soil conditions to control excessive settlement. The embankment and RI were placed on a lacustrine deposit comprising layers with high organic matter content and soft clays that extended up to 200 m below ground surface. The effects of RI installation were reviewed using an inclinometer and benchmark data. Proof static load tests (SLT) and CPT were performed after RI installation to verify RI performance. CPTs were completed in the soil adjacent to the RI, as tested by the SLT. Different time spans were considered after RI installation for the CPT to assess the evolution of soil properties. The SLT uses the estimated working loads factored in by at least 20%. The CPT results showed that after a relatively short period of RI installation, the soil properties were similar to the initial properties. SLT results showed that RI capacity and head displacements were within the admissible ranges, considering that they had no competent bearing stratum, demonstrating the effectiveness of the ground improvement method. The results of both tests demonstrate the effectiveness of RI as a ground improvement technique for lacustrine soft clay in Bogotá.