Shaft resistance of a pile in rock based on the modified Hoek–Brown criterion

• A method for calculating the shaft resistance a pile in rock is presented.
• Shaft resistance is generalized for the modified Hoek–Brown criterion.
• It is assumed that the horizontal stresses are directly proportional to the vertical stresses.
• There are not limitations due to the deformability of the rock mass.
• All the formulation can be programmed in a spreadsheet.