6.3.1 Direct input method
As shown in Figure 6.10，compute the vertical stress（σy）and the horizontal stress（σx）at a point in the ground in a free field surface：
where
γm andγsat are the moisture unit weight and the saturated unit weight of soil，respectively.u is the porewater pressure；
K0 is the coefficient of at⁃rest earth pressure；
h1 and h2 are the depth of the groundwater level and the depth between the point and the groundwater level，respectively.
Figure 6.10 Computation of the initial stresses
As shown in Figure 6.11，the initial stresses in sloping ground with no groundwater is
Figure 6.11 The stresses in sloping ground
If there is groundwater seepage，the porewater pressure can be estimated using the flow net method and thenσ′y andσ′x can be determined accordingly.The shear stress 
xy＝1／2γ′h sinα.