Nonlinear analysis of laterally loaded rock-socketed shafts

In this paper, a nonlinear continuum method is developed to predict the load-displacement response of drilled shafts under lateral loading. The method can consider drilled shafts in a continuum consisting of a soil layer overlying a rock mass layer. The deformation modulus of the soil is assumed to vary linearly with depth, and the deformation modulus of the rock mass is assumed to vary linearly with depth and then to stay constant below the shaft tip. The effect of soil and/or rock mass yielding on the behavior of shafts is considered by assuming that the soil and/or rock mass behaves linearly elastically at small strain levels and yields when the soil and/or rock mass reaction force p (force/length) exceeds the ultimate resistance p(ult) (force/length). For the calculation of the ultimate resistance p(ult) of the soil, methods that are available in the literature are used. To calculate the ultimate resistance p(ult) of the rock mass, a method based on the Hoek-Brown strength criterion is proposed. The proposed method is verified by comparing its results with available elastic solutions and field test data, and it is finally applied in the design of a bridge foundation in Massachusetts.