Water pore pressure:
For the soil profile given below determine the total and effective stresses at point A. What will be the total, neutral (water pore pressure ) and effective stresses at point if the ground water table rises to the ground surface?, Will there be any change effective stress at point A if the water table rise 2m above the ground surface ?
Solution
Water pore pressure
NOTE
What is the pore water pressure?
Pore water pressure is the pressure of groundwater held between soil or rocks in the gaps (or ‘pores’) between particles. It is affected by the soil type, water flow conditions and level of the water table.
Effective stress can be defined as the stress that keeps particles together. In soil, it is the combined effect of pore water pressure and total stress that keeps it together. It can also be defined in equation form as the total stress minus the pore pressure.
Total stress at a point is defined as the sum of the stress exerted by the total weight (solids plus water) of the soil/rock and the load on the foundation.
