Evaluation of interpretation criteria for drilled shafts with tip post-grouting

This paper evaluates the effects of tip post-grouting on various capacity interpretation criteria for drilled shafts under compression loading. A wide array of load test data for drilled shafts constructed using three post-grouting methods, including tube-a-manchette, flat jack, and jet grouting, is utilized for the analysis. The load tests were divided based on the different tip post-grouting methods, then they were further divided based on the soil conditions (undrained or drained). The interpreted capacity and displacement at the interpreted capacity are examined for each interpretation criterion. Furthermore, the interpreted results were compared with current studies on drilled shafts that are not subjected to tip post-grouting techniques to determine the effects of post-grouting methods. Based on these analyses, the normalized load–displacement curves and the relationships between various interpretation criteria for drilled shafts with tip post-grouting are established. The drilled shafts subjected to any post-grouting method produced higher capacity and yield larger displacement with the same amount of normalized capacities for undrained and drained soils compared to drilled shafts not subjected to any post grouting procedures. Among the three grouting methods studied, the jet grouting method can produce a greater capacity than the other methods, especially for drained soil conditions. Finally, specific recommendations to guide the design of drilled shafts with tip post-grouting are provided.