Table 2. Joint Properties Property Horizontal Joints Vertical Joints Normal stiffness (GPa/m) 50 50 Shear stiffness (GPa/m) 5 5 Friction angle (degrees) 30 35 Cohesion 0 0 Dilation angle (degrees) 0 5 Initial aperture (mm) 20 10 Residual aperture (mm) 10 5