 a, $$\ \tau_\mathrm{a}$$ Adhesion or external shear strength kPa c, $$\ \tau_\mathrm{c}$$ Cohesion or internal shear strength kPa f Function - F Horizontal force kN Fh Horizontal force on soil element kN Fv Verical force on soil element kN Fn Normal force on soil element kN Fs Shear force on soil element kN g Gravitational constant (9.81) m/s2 G Gravitational vertical force kN h Height of the dam/soil m Ka Coefficient of active failure - Kp Coefficient of passive failure - N Force normal to the shear plane kN S Shear force on the shear plane kN α Orientation of shear plane (Mohr circle) rad β Angle of the shear plane (active & passive failure) rad δ External friction angle or soil/interface friction angle rad φ Internal friction angle rad σ Normal stress kPa σh Horizontal normal stress (principal stress) kPa σv Vertical normal stress (principal stress) kPa σin Internal normal stress kPa σex External normal stress or soil interface normal stress kPa $$\ \tau$$ Shear stress kPa $$\ \tau_{\text {in }}$$ Internal shear stress kPa $$\ \tau_{\text {ex }}$$ External shear stress or soil interface shear stress kPa ρg Density of the soil ton/m3 μin Internal friction coefficient - μex External friction coefficient -