“…A new method for determining the values of Po from the pressuremeter tests was developed by the author (Alzubaidi 2014), the method depend mainly on the facts that after drilling a borehole, the value of Po will be equal to zero (Po = 0), where stress relief will be occurred at the borehole wall, when a pressuremeter test will be conducted, any small increase in the pressure applied to the bore hole wall, there is a positive increase in the volume of the borehole, these increases occur before and after reaching the values of Po. The second fact, that the soil act as elasticperfectly plastic material after Po.…”