 a, $$\ \tau_\mathrm{a}$$ Adhesion or adhesive shear strength. kPa A Adhesive shear force on the blade. kN c, $$\ \tau_\mathrm{c}$$ Cohesion or cohesive shear strength. kPa C1 Cohesive shear force on the shear plane. kN C2 Cohesive shear force on the pseudo blade (front of the wedge). kN C3 Cohesive shear force on bottom of the wedge. kN Fh Horizontal cutting force. kN Fv Vertical cutting force. kN G1 Weight of the layer cut. kN G2 Weight of the wedge. kN hb Blade height. m hi Layer thickness. m I Inertial force on the shear plane. kN N1 Normal force on the shear plane. kN N2 Normal force on the pseudo blade (front of the wedge). kN N3 Normal force on bottom of the wedge. kN N4 Normal force on the blade. kN K1 Sum of N1 and S1 on the shear plane. kN K2 Sum of N2 and S2 on the pseudo blade (front of the wedge). kN K3 Sum of N3 and S3 on bottom of the wedge. kN K4 Sum of N4 and S4 on the blade. kN L1 Length of the shear plane. m L2 Length of the pseudo blade (front of the wedge). m L3 Length of the bottom of the wedge. m L4 Length of the blade. m L5 Length of the line from the tip of the blade to the opposite side of the wedge and perpendicular to this side. m L6 Length of the line from point A to the intersection point of the previous line with side A-C. m L7 Distance from the acting point of the pore pressure force on side A-C to the intersection point of the previous line L6 with side A-C. m R1 Acting point forces on the shear plane. m R2 Acting point forces on the pseudo blade (front of the wedge). m R3 Acting point forces on the bottom of the wedge. m R4 Acting point forces on the blade. m S1 Shear (friction) force on the shear plane. kN S2 Shear (friction) force on the pseudo blade (front of the wedge). kN S3 Shear (friction) force on the bottom of the wedge. kN S4 Shear (friction) force on the blade. kN W1 Pore pressure force on the shear plane. kN W2 Pore pressure force on the pseudo blade (front of the wedge). kN W3 Pore pressure force on the bottom of the wedge. kN W4 Pore pressure force on the blade. kN vc Cutting velocity. m/sec α Blade angle. ° β Shear angle. ° θ Wedge angle. ° φ Internal friction angle. ° δ External friction angle. ° λ Internal friction angle on pseudo blade. °