E1001A-171107
24
12.2 CLEANING THE FILTER
The filter mounted on the copper line connected to the Port No. 1 must be checked
periodically. If it gets plugged, it will be difficult to deflate the probe
. To check it,
proceed as follows:
Remove the front panel from the control unit box as indicated above.
Unscrew the brass nut on the copper tube of port No. 1 with a 9/16" open wrench.
Unscrew the 2 nuts on both sides of the filter and remove the filter from instrument.
Check if filter is clean by blowing some air in it.
If it is plugged, replace it.
If no spare filter is available, you can clean it as follows: open filter housing with 2-
3/4
"
wrenches and remove filter cartridge. Clean all parts with clean water and re-install filter,
following the opposite procedure of the removal.
Be sure that the arrow on the filter points in the same direction as before.
After saturating the pressuremeter, put it under pressure up to 10,000 kPa and check for
leaks. If the filter leaks, tighten up the nuts or put a new filter assembly.
12.3 SPLICING THE TECALAN TUBING
1. Cut the tubing, at a right angle,
cleanly.
2. Install a socket in a vice. Do not
overtighten, do not misshape the
socket
3. Screw the tubing into the socket
thoroughly by rotating counter
clockwise. Then, unscrew one
quarter of a turn (
very important
)
4. Install the socket-fitted tubing
vertically
5. Insert the coupling into the socket
by pushing and screwing the
coupling. Do not overtighten. Keep
a 0.2 to 0.8 mm spacing between
the socket and the coupling.
13
DATA REDUCTION
The raw test data are corrected to compensate for membrane resistance, system
compressibility and the hydraulic head between the control unit and the probe.
The modulus is determined with the following relation:
E
m
=2 (1+ν) (Vo +V
m
) (ΔP/ΔV)
Where:
E
m
= Pressuremeter modulus
v = Poisson's ratio
V
o
= Theoretical volume of the measuring portion of the uninflated probe at 0
volume reading at the ground surface