It is known that the angle of internal fricticen for the soil comprising a granular deposit is $37^{\circ}$. At one depth in the deposit, the lateral pressure is $45 \mathrm{kPa}$, and this is considered the value of the minor principal stress. Use the Mohr's circle analysis to determine the maximum vertical pressure (major principal stress) that can be applied (ie, the vertical pressure for incipient shear).