Rule of Thumb = Friction Angle - 30 q0&Wk"X%rr
x6LjcRS|
For more details, please read _u>t3RUA
ajW[eyX
Bolton, M.D. (1986) The strength and dilatancy of sands xE%O:a?S
!#q{Z>H`
Vermeer & DeBorst (1984) Non-associated plasticity for soils, concrete and rock