Improvement for Determining the Axial Capacity of Drilled Shafts in Shale in Illinois.

摘要

For project ICT R27-99, Improvement for Determining the Axial Capacity of Drilled Shafts in Shale in Illinois, the research team studied load transfer mechanisms of drilled shafts that are fully or partially embedded in weak, clay-based sedimentary rocks (e.g., weak shales) encountered in Illinois and developed a design procedure that will improve safety and reduce IDOTs deep-foundation costs for future bridge structures. The main objectives of Task 1 of this study were to review existing literature and develop a drilled shaft load test database for weak, clay-based sedimentary rocks and to evaluate existing design methods. Objectives of Task 2 were to perform field exploration and laboratory tests at five IDOT bridge sites to develop new methods for characterization of weak shale encountered at shallow depths in Illinois. Objectives of Task 3 were to use the load test database compiled herein and data from five IDOT bridge sites to develop new correlations for the design of drilled shafts in weak shale. Also in Task 3, resistance factors were developed for designing drilled shafts using a load and resistance factor design (LRFD) framework. Drilled shafts at three IDOT sites were re-designed as a part of Task 3 to demonstrate the effectiveness of developed design correlations.