A civil engineering project requires the excavation of a deep trench for laying a foundation in a site with saturated clayey soil. The trench dimensions are 10 meters deep, 6 meters wide, and 20 meter long. The groundwater table is encountered at a depth of 3 meters below the ground surface. The unit weight of the soil is 18 kN/m³, and the saturated unit weight is 20 kN/m³. Determine the total vertical stress, effective vertical stress, and pore water pressure at the bottom of the trench.