 a1, a2 Coefficients for weighted permeability - a, $$\ \tau_\mathrm{a}$$ Adhesion or external shear strength kPa A Adhesive force on the blade kN c, $$\ \tau_\mathrm{c}$$ Cohesion or internal shear strength kPa C, C1 Force due to cohesion in the shear plane kN C2 Force due to cohesion on the front of the wedge kN C3 Force due to cohesion at the bottom of the wedge kN Fh Horizontal cutting force kN Ff1 Friction force on the shear surface kN Ff2 Friction force on the blade kN Fn1 Normal force on the shear surface kN Fn2 Normal force on the blade kN Fv Vertical cutting force kN Fd1 Deviation force on the shear surface kN Fd, d2 Deviation force on the blade kN Fx1, 2 Cutting force in x-direction kN Fy1, 2 Cutting force in y-direction kN Fz1, 2 Cutting force in z-direction kN g Gravitational constant (9.81) m/s2 G, G1 Gravitational force on the layer cut kN G2 Gravitational force on the wedge kN hi Initial thickness of layer cut m hb Height of blade m hb,m Effective height of the blade in case Curling Type m I Inertial force on the shear plane kN ki Initial permeability m/s kmax Maximum permeability m/s km Average permeability m/s K1 Grain force on the shear plane kN K2 Grain force on the blade or the front of the wedge kN K3 Grain force on the bottom of the wedge kN K4 Grain force on the blade (in case a wedge exists) kN ni Initial porosity % nmax Maximum porosity % N1 Normal force on the shear plane kN N2 Normal force on the blade or the front of the wedge kN N3 Normal force on the bottom of the wedge kN N4 Normal force on the blade (in case a wedge exists) kN p1m Average pore pressure on the shear surface kPa p2m Average pore pressure on the blade kPa Pc Cutting power kW R1 Acting point of resulting forces on the shear plane m R2 Acting point of resulting forces on the blade m R3 Acting point of resulting forces on the bottom of the wedge m R4 Acting point of resulting forces on the blade (in case a wedge exists) m S1 Shear force due to friction on the shear plane kN S2 Shear force due to friction on the blade or the front of the wedge kN S3 Shear force due to friction at the bottom of the wedge kN S4 Shear force due to friction on the blade (in case a wedge exists) kN vc Cutting velocity component perpendicular to the blade m/s vd Cutting velocity, drag velocity m/s vr1 Velocity of grains in the shear surface m/s vr2 Relative velocity of grains on the blade m/s vd1 ​​​​​​​ Deviation velocity of grains in the shear surface m/s vd2 ​​​​​​​ Deviation velocity of grains on the blade m/s vx1,2 Velocity of grains in the x-direction m/s vy1,2 Velocity of grains in the y-direction m/s vz1,2 Velocity of grains in the z-direction m/s W Width of blade m W1 Force resulting from pore under pressure on the shear plane kN W2 Force resulting from pore under pressure on the blade/ front wedge kN W3 Force resulting from pore under pressure on the bottom of the wedge kN W4 Force resulting from pore under pressures on the blade, wedge kN Z Water depth m $$\ \alpha$$ Cutting angle blade rad β Shear angle rad ε Dilatation - φ Angle of internal friction rad φe Angle of internal friction perpendicular to the cutting edge rad λs Strengthening factor - λ1 Acting point factor for resulting forces on the shear plane - λ2 Acting point factor for resulting forces on the blade or front of wedge - λ3 Acting point factor for resulting forces on the bottom of the wedge - λ4 Acting point factor for resulting forces on the blade - δ External friction angle rad δe External friction angle perpendicular to the cutting edge rad $$\ \iota$$ Deviation angle blade rad ρs Density of the soil ton/m3 ρl Density water ton/m3 θ Wedge angle rad