Reliability Based Design for Drilled Shafts for Slope Stabilization

An ideal of drilled shafts aims to provide maximum safety while minimizing the construction cost. A reliability based optimization design method for a drilled shaft stabilized slope system is presented in this paper. The drilled shaft stabilization mechanisms for the reinforced slope were taken into account through the concept of soil arching, which was quantified by the load transfer factor in the limiting equilibrium analysis. However, due to the inherent uncertainties of the soil properties and the model error of the semi-empirical load transfer equation, a modification of the deterministic method into a probabilistic method is developed in this paper. The Monte Carlo simulation (MCS) for the soil properties described by the log-normal distributions was employed to calculate the probability of failure (reliability index β) for the drilled shafts reinforced slope system. The developed theories were coded into a computer program for analyzing complex slope profile conditions. Finally, a case study (Ohio ATH-124 slope) was presented to illustrate the step by step design procedure using the developed probability approach.