A wall with a smooth vertical back and 9 metres high retains a moist cohesionless soil with a horizontal surface. The soil weighs 15 kN/m3 and has an angle of internal friction of 30°. Verify the total earth pressure at rest and its location. If, subsequently, the water table rises to the ground surface, State the increase in earth pressure at rest. Assume effective unit weight of soil as 9 kN/m3.