| A practical methodology for stability analysis and design of drilled shafts reinforced slopes was developed utilizing limiting equilibrium method of slices. Complex soil stratifications and general failure slip surfaces can be handled in the developed method. The effect of soil arching due to the presence of the drilled shafts was accounted for by using a load transfer factor. The numerical values of the load transfer factor were developed based on 3-D FEM parametric study results. Many of the design variables controlling the slope/shaft systems, such: drilled shafts size, shafts location, and the required spacing between the drilled shafts can be successfully determined from the developed method. The optimum location can be searched for and determined from the developed methodology. The global factor of safety for slope/shaft systems and the forces acting on the stabilizing drilled shafts due to the moving ground can be successfully estimated.;For the purpose of verifying the validity of the proposed design methodology, the results of a field load testing program on the fully instrumented drilled shafts installed on an existing failed slope together with the companion 3-D FEM simulations are presented. This real case was analyzed using the proposed analysis and design methodology, the analysis results were compared with the FEM results, and it is found that they are in good agreement.;In addition, Real-time instrumentation and monitoring were carried out for three landslide sites in the Southern part of Ohio. Various types of instruments were extensively installed inside the stabilizing shafts and the surrounding soils to monitor and better understand the behavior of slope/shaft systems. The field instrumentation and monitoring processes have provided excellent and unique information on the lateral responses of shafts undergoing slope movements. Also, the results of the instrumented cases have provided that the structural design (moments, shear, lateral deflection, and shaft tip fixity) of the shafts are overestimated (i.e., estimated forces acting on the shafts are high), and the geotechnical design (FS of slope/shaft system: movement and rate of movement) is achieved. |
