Vibrating Wire Piezometer

[priyainuk2009]

We have installed Vibrating Wire Piezometer in Underground Metro site construction at 25m depth from ground.
The initial reading recorded was 0.177MPa on Nov-11 & present reading is 0.159MPa.As per AAA levels the 'Alarm Level' proposed for change in pressure is 0.20MPa. Our latest readings shows that change in pore pressures are very close to 'Alarm Level'.
What this signifies & how much impact it has on Underground Constructions?
Thanks in advance
Debasis

 

[Ron]

If you don't understand the need or the results of a piezometer, why did you install them?

 

[dgillette]

Am I reading the numbers right? If so, you've had a decrease of 0.018 MPa, compared to the alarm level of 0.2 MPa. Should that be 0.02 MPa for the alarm level? (Total overburden stress is only about 0.5, right? I don't normally work in SI units, so I'm a bit awkward at it.)

Now, for your project, is a DECREASE in PWP a problem, or only an INCREASE? Could be very different in effect.