Monitor pore water pressure for calculation of embankment stability and landfill dike.
Monitor ground improvement techniques such as vertical drains, sand drain and dynamic compaction .
Monitor dewatering schemes for excavations and under ground openings
Monitor seepage and ground water movement in embankment , landfill dike and dam
Monitor water drawn down during pumping test.
STANDPIPE PIEZOMETERS
Porous & Sreened Filters for observation wells and standpipe piezometer.
Casagrande type piezometer tips-(60 micron) 1 1/2 -inch diameter, porous staone or porous plastic in 6, 12, 18 or 24 inch lengths.
slotted PVC pile -screen size from 0.010 inch and larger, various lengths, 1 1/2 inch pipe .
Drivable well points 1 1/4 inch & 2 inch diameter.
Geonor M-206 push-in type, porous tipm, sintered bronze filter (replaceable) -adapted for E-rod threads.
Riser pipe -PVC or steel, standard or flush-coupled, 1/2 inch or larger
Bentonite Pellets : (1/4", 3/8" or 1/2" sizes) seal pneumatic, electric, standpipe and well-point piezometers in boreholes.
EXAMPLE PROBLEM
An artesian presure exists in the lower sand layer of the profile shown above, with a piezometer surface 1 m. above ground surface.Determine the total stress, pore presure and effective stress at point A,B and C
Point A
Point B
The pore pressure in the lower sand layer is determined by the height of water in the piezometer.
Point C
A staedy - state seepage condition exists in the clay layer with water flowing upward.The pore presure must, therefore, be evaluated by first calculating the pressure head at point C.
Establish a datum at the bottom of the clay layer.
