 formula_1

Jaky's coefficient has been proved later to be also valid for normally consolidated granular deposits and normally consolidated clays.From the purely theoretical point of view, the very simple formula_2 formula, works ideally for the two extreme values of formula_3, where for formula_3 = 0o it gives formula_5 referring to hydrostatic conditions and for formula_3 = 90o (theoretical value) it gives formula_7 referring to a frictional material that can stand vertically without support, thus, exerting no lateral pressure.These extreme cases are enough evidence that the correct expression for the coefficient of earth pressure at rest is the formula_8.