7 Reporting

7.1 General

In the presentation of test results, the information should be easily accessible, for example in tables or as a standard archive scheme. Presentation in digital form is permissible for easier data-exchange.

Subclause 7.2 indicates the information required in

  • the field record of test results,
  • the test report, and
  • every table and every plot of test results.

The field report, completed at the project site, and the test report shall include the information given in 7.2. The test results shall be reported to enable a third party to check and understand the results.

During the cone penetration test, particulars or deviations from this part of ISO 22476 should be recorded, which can affect the results of the measurements and the corresponding penetration length.

7.2 Reporting of test results

7.2.1 General information Field report Test report Every plot
a) Reference to this part of ISO 22476 x x
b) Application class x x x
c) Test type (TE1 or TE2) x x x
d) Particulars or deviations from this part of ISO 22476 x x
e) Company executing the test x x
f) Name and signature of equipment operator executing the test x
g) Name and signature of field manager responsible for the project x
h) Depth to the groundwater table (if recorded) x x
i) Pore pressure information (for instance from piezometers) if relevant and available x
j) Depth of predrilling or trenching depth x x x
k) Type of materials encountered (if possible) x x
I) Depth of penetration and possible causes of any interruptions (like dissipation tests) x x _
m) Stop criteria applied, like target depth, maximum penetration force or inclination x x
n) Method of back filling the hole, if applicable x
o) Observations done in the test, for example:
  • presence of stones,
  • noise from the pushing rods,
  • incidents,
  • buckled rods,
  • significant changes in zero or reference readings
x x
p) Specific arrangements that deviate from common set up of thrust machine (like a jack-up platform) x x
7.2.2 Location of the test Field report Test report Every plot
a) Identification of the test      
b) Elevation of the cone penetration test x   x
c) Local or general coordinates x   x
d) Reference system and tolerances x  
e) Reference elevation to a known datum x x

The contract shall specify who is responsible for providing the coordinates and levels of investigation points.

7.2.3 Test equipment Field report Test report Every plot
a) Cone penetrometer type x x
b) Geometry and dimensions cone penetrometer x
c) Type of thrust machine used, pushing capacity, associated jacking and anchoring systems x
d) Manufacturer of cone penetrometer x x
e) Identification number of the penetrometer x x
f) Measuring ranges of the transducers x x
g) Date of last calibration of sensors x x
h) Filter location x x
i) Net area ratio x
7.2.4 Test procedure Field report Test report Every plot
a) Date of the test x x x
b) Starting time of the test x x
c) Clock time during the test x x
d) Depth of the start of penetration with reference to the ground surface x x
e) Saturation fluid used in pore pressure system (if piezocone) x x
7.2.5 Test results (depending on application class) Field report Test report Every plot
a) Measured and calculated parameters according to 6.1 and 6.3 x x x
b) Corrected parameters according to 6.2 x
c) Zero and/or reference readings of measured cone resistance, sleeve friction and, if applicable, pore pressure before and after the test and zero drift (in engineering units), for application classes 1 and 2. x x
d) Corrections applied during data processing (e.g. zero drifts) x
e) in situ pore pressure measurements (if recorded) x x
f) Inclination of the cone penetrometer to the vertical axis, for a maximum penetration depth interval of 1 m, if applicable x

7.3 Presentation of test results

In the graphical presentation of test results, the following axis scaling should be used:

— Penetration depth z: 1 scale unit = 1 m;
— Cone resistance qc, qt: 1 scale unit = 2 MPa or 0,5 MPa;
— Sleeve friction fs, ft: 1 scale unit = 0,05 MPa;
— Pore pressure u: 1 scale unit = 0,2 MPa or 0,02 MPa;
— Friction ratio Rf, Rft: 1 scale unit = 2 %;
— Pore pressure ratio Bq: 1 scale unit = 0,5. One scale unit should be 1 cm.

A different scaling may be used in the presentation if the recommended scaling is used in an additional plot. The recommended scaling can for example be used for general presentation, whereas selected parts may be presented for detailed studies, using a different scaling. In clays, and where the test results are to be used for interpretation of soil parameters (application classes 1 and 2, see Table 2), it is particularly important to use enlarged scaling in the presentation of test results.

The axis scaling for dissipation test results (cone resistance qc, pore pressure u and time t) shall suit the measured values.

NOTE A common presentation format is to use linear scales for qc and u and a logarithmic scale for t.

7.4 Presentation of test results and calculated parameters

The test results shall be presented as continuous profiles as a function of the penetration depth (for application classes 1, 2 and 3) or penetration length (for application class 4).

The test results (according to the application class and test type) that shall be presented are:

— Cone resistance — depth/length qc(MPa) — z (m);

— Sleeve friction — depth/length fs(MPa) — z (m);

— Measured pore pressure — depth/length u1, 2, 3 (MPa) — z (m);

— Inclination — depth/length α (°) — z (m) or tabulated, as function of depth. Penetration depth is the measured length corrected for the measured inclination.

The units used may be kilopascals (kPa), depending on the scale of measured parameters.

Presentation of the results of cone penetration tests according to application classes 1 and 2 shall, if required, include at least tabular data according to 7.1.

For application class 1, corrected cone resistance (qt) shall be plotted in addition and the corrected sleeve friction (ft) may be plotted in addition. The corrected parameters should be used in further processing of the data. An exception is made for testing of coarse-grained materials, where the effect of the end area correction is negligible.

In situ pore pressure can be estimated from the location of the groundwater table, or preferably by local pore pressure measurements. It can also be evaluated from the test results by performing dissipation tests in permeable layers. The total overburden stress profile can be determined from density measurements in situ or from undisturbed samples in the laboratory. If adequate information is lacking, an estimate of the density may be obtained by use of a classification chart based on the results from the cone penetration test and local experience.

For further processing of the measured data, the following relationships should be used, if appropriate:

— Excess pore pressure Δu = u — u0;

— Net cone resistance qn = qt — σv0;

— Friction ratio Rf = (fs/qc) × 100 %;

— Corrected friction ratio Rft = (fs/qt) × 100 % (if known, ft shall be used instead of fs);

— Pore pressure ratio Bq = (u2 — u0)/(qt — σv0) = Δu2/qn,

— Normalized excess pore pressure U = (ut — u0)/(ui — u0);

Knowledge of the following parameters is required for processing of the test results:

in situ, initial pore pressure versus depth u0 (MPa) versus z (m);

— Total overburden stress versus depth σv0 (MPa) versus z (m).

These parameters, or additional calculated values, can be used for both identification of strata and classification of soil types, and as basic input values for evaluation in terms of engineering parameters.

The friction ratio shall be presented on the plot. Presentation of the other calculated parameters is optional because they are dependent on interpretation.

ISO 22476-1:2012 Field testing — Part 1: Electrical cone and piezocone penetration test