6 Test results
6.1 Data sheet and field print-out
6.1.1 Data sheet in procedure A
All the data as shown in F.1 shall be fully and carefully recorded except readings at 1 s.
The operator shall authenticate the data sheet by signing and giving his full name in capital letters.
6.1.2 Site print-out in procedure B
At least the following information shall be printed at site for any test:
- a) before the start of the test:
- 1) the operator's identification;
- 2) a statement that the test will comply with the present standard: ISO 22476-4;
- 3) the data logger parameters;
- pressurizing and read-out unit number (and data logger number if separate from the unit);
- memory device number;
- information input for test identification: as listed in 5.4.
- b) at the start of the test:
- 1) date (year, month, day, hour and minute) at the start of the test.
- c) at the end of each pressure hold:
- 1) loading pressure step number in the series;
- 2) one liquid pressure reading in the time interval between the start of the pressure hold and 15 s later, correct to at least three significant digits;
- 3) injected volume readings 30 s and 60 s after the start of the pressure hold rounded to the nearest cm3;
- 4) the difference between these two readings i.e. ΔV60/30;
- 5) the difference between the 60 s injected volume readings of the current and preceding pressure hold ΔV60/60.
- d) at test completion:
- 1) date and time at completion of test;
- 2) computer plot of volume readings Vr against pressure readings pr at 60 s giving the raw pressuremeter curve;
- 3) the operator shall authenticate the full print-out by signing and giving his full name in capital letters.
6.1.3 Raw pressuremeter curve
The raw pressuremeter curve shall be obtained by plotting CU readings Vr versus pr, each at 60 s. In procedure B, the raw pressuremeter curve shall be provided by the data logger printer.
6.2 Corrected pressuremeter curve
The corrected pressuremeter curve (Figure 5) shall give the probe central measuring cell volume V as a function of the pressure p applied to the pocket wall:
V = f(p)
- p is the pressure at 60 s applied by the outer cover of the probe on the pocket wall, after correction for hydrostatic head and pressure loss (see D.1.2 and D.1.3);
- V is the corresponding volume of liquid injected into the probe, after zeroing (see B.4.1) and after correction for volume loss (see D.1.4).
The corrected pressuremeter curve shall be defined by the succession of coordinates (p, V) shown in Figure 5. At the start of the pressuremeter test, the pocket wall shall be loaded by the probe until it returns approximately to its original condition. The slope of the pressuremeter curve shall then be sensibly constant. After the end of this stage, the probe radial expansion rate shall increase rapidly as the pressure increases.
- 1 corrected pressuremeter curve
- 2 corrected creep curve
The creep curve shall be plotted as shown in the lower part of Figure 5, (according to D.3). Changes in the creep rate can identify important events in the test.
6.3 Calculated results
The pressuremeter test parameters shall be obtained from the information recorded on the data sheet (procedure A) or either on the print-out or on the memory device (procedure B).
First, the data shall be examined as recorded to see if and how much of the curve can be analysed (see Annex D).
Next, the methods described in Annex D shall be used
- to determine the pressuremeter creep pressure pfM (D.3),
- to determine the Ménard pressuremeter limit pressure pLM (D.4),
- to calculate the Ménard pressuremeter E-modulus EM (D.5).
The test results shall be reported in such a fashion that third parties are able to check and fully understand the results.
7.2 Field report
The field report shall contain all data collected in the field (see 5.4 and 6.1). The field report shall be signed by the operator in charge (6.1.1 and 6.1.2).
7.3 Test report
The test report shall include the pressuremeter test identification parameters (see 5.4) and the Ménard pressuremeter test files (see 6.1). The test report shall be signed by the field manager responsible for the project.
7.3.1 Ménard pressuremeter test file
The file for a single pressuremeter test shall include, as shown in Annex F, the corrected data, the pressuremeter curve and the pressuremeter test parameters.
It shall also contain the field reports including a copy of either the signed data sheet (see 6.1.1) or of the signed print-out (see 6.1.2) and in the case of procedure B the corresponding readable electronic data recorded on the memory device as described in 4.7.
The file shall include the following data as a minimum:
- a) reference to this part of ISO 22476;
- b) type of procedure used for the test: A or B;
- c) identification number of the sounding where the pressuremeter test was performed;
- d) elevation of the test or its depth from the top of the sounding or casing;
- e) type of drilling technique and drilling tool used to create the pocket and the top and bottom elevations of the drilling stage;
- f) time of completion of the test pocket, correct to the minute;
- g) type, make, and serial number of the control unit and of the data logger if separate from the control unit; h) information on the recent checks of all control and measuring devices used (see B.1);
- i) time at the start of the test, correct to the minute;
- j) type of probe used (E or G) and its details (slotted tube, short probe, long probe), the volume loss and the pressure loss calibration test results as defined in Annex B;
- k) differential pressure (pr – pg) at CU elevation;
- l) table of the liquid pressure and volume readings at 1 s (procedure B only), 15 s, 30 s and 60 s at each pressure loading level;
- m) p, V coordinates of each point used to plot the corrected pressuremeter curve;
- n) all mishaps during the test (such as a probe bursting);
- o) elevations of the pressuremeter sounding top zN and the pressure transducers zc as shown in F.1 and Figure D.1;
- p) elevation of the drilling fluid level when applicable and the ground water table when known: zw;
- q) name of the company performing the pressuremeter sounding i.e. drilling and testing;
- r) corrected pressuremeter curve and the methods used for pressure and volume loss corrections;
- s) Ménard pressuremeter modulus EM and the method used to obtain it;
- t) Ménard pressuremeter limit pressure pLM and the method used to obtain it;
- u) creep pressure pfM and the method used to obtain it;
- v) ground identification and description according to ISO 14688-1 and ISO 14689-1 for the pressuremeter test pocket.
7.3.2 Pressuremeter tests log
A pressuremeter tests log, as shown in F.2, shall include as a minimum:
- a) reference to this part of ISO 22476;
- b) type of procedure used: A or B;
- c) pressuremeter soundings layout drawing and, if appropriate, the grid references of the soundings;
- d) ground surface elevation zN at the pressuremeter borehole measured from a stated datum;
- e) level of the fluid in the hole in the ground resulting from the pressuremeter sounding at specified times, and the elevation of the ground water table, if known;
- f) pocket formation technique with reference to Table C.1 and the dates at which the various pockets were formed;
- g) pressuremeter sounding inclination and direction;
- h) information on the ground strata;
- i) graphical representation of the pressuremeter parameters as a function of depth, with a depth scale and the following values:
- Ménard pressuremeter modulus EM;
- Ménard pressuremeter limit pressure pLM;
- pressuremeter creep pressure pfM.
Pressures and pressuremeter moduli shall be quoted to at least two significant digits.
NOTE For the same site, it is recommended to have a common scale for all pressuremeter logs.
- j) comments on the test procedure, mishaps and any other information which may affect the test results.