2.4.2.6 Tests on samples
(1)P Samples for testing shall be selected so as to cover the range of index properties of each relevant stratum.
(2) For a fill or a stratum of sand or gravel, reconstituted specimens may be tested. Reconstituted specimens should have approximately the same composition, density and water content as in-situ material.
| Parameter | Type of soil | |||||||
| Clayey soil | Silty soil | Sandy, gravelly soil | ||||||
| Type of specimen | Type of specimen | Type of specimen | ||||||
| Undisturbed | Disturbed | Remoulded | Undisturbed | Disturbed | Remoulded | Disturbed | Remoulded | |
| Geological description and soil classification | X | X | X | X | X | X | X | X |
| Water content | X | (X) | (X) | X | (X) | (X) | (X) | (X) |
| Bulk density | X | (X) | — | X | (X) | — | — | — |
| Minimum and maximum densities | — | — | — | (X) | (X) | (X) | X | X |
| Atterberg (consistency) limits | X | X | X | X | X | X | — | — |
| Particle size distribution | X | X | X | X | X | X | X | X |
| Undrained shear strength | X | — | — | (X) | — | — | — | — |
| Permeability | X | — | — | X | (X) | (X) | (X) | (X) |
| Sensitivity | X | — | — | — | — | — | — | — |
| X = normal to determine (X) = possible to determine, not necessarily representative — = not applicable NOTE For some types of soil, further tests may be considered, for example the determination of organic content, particle density and activity. |
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(3) Laboratory tests to determine parameters for geotechnical calculations are given in Table 2.3.
(4) Suitable routine laboratory tests for rock samples giving the necessary basis for the description of the rock material are as follows:
- the geological classification;
- the density or bulk mass density (ρ) determination;
- the water content (w) determination;
- the porosity (n) determination;
- the uniaxial compression strength (σc) determination;
- the Young's modulus of elasticity (E) and Poisson's ratio (ν) determination;
- the point load strength index test (Is,50).
(5) The classification of rock core samples will normally comprise a geological description, the core recovery, the Rock Quality Designation (RQD). the degrees of induration, fracture log, weathering and fissuring. In addition to the routine tests mentioned in 2.4.2.6 (4) for rocks, other tests may be selected for different purposes, e.g. density of grains determination, wave velocity determination, Brazilian tests, shear strength of rock and joints determination, slake durability tests, swelling tests and abrasion tests.
(6) The properties of the rock mass including the layering and fissuring or discontinuities may be investigated indirectly by compression and shear strength tests along joints. In weak rocks, complementary tests in the field or large-scale laboratory tests on block samples may be made.
| Geotechnical parameter | Type of soil | |||||
| Gravel | Sand | Silt | NC clay | OC clay | Peat organic clay | |
| Oedometer modulus (Eoed); compression index (Cc); [one-dimensional compressibility] |
(OED) (TX) |
(OED) (TX) |
OED (TX) |
OED (TX) |
OED (TX) |
OED (TX) |
| Young's modulus (E); Shear modulus (G) |
TX | TX | TX | TX | TX | TX |
| Drained (effective) shear strength (c'), (φ') | TX SB |
TX SB |
TX SB |
TX SB |
TX SB |
TX SB |
| Residual shear strength (c'r), (φ'r) | RS (SB) |
RS (SB) |
RS (SB) |
RS (SB) |
RS (SB) |
RS (SB) |
| Undrained shear strength (cu) | — | — | TX DSS SIT |
TX DSS (SB) SIT |
TX DSS (SB) SIT |
TX DSS (SB) SIT |
| Bulk density (ρ) | BDD | BDD | BDD | BDD | BDD | BDD |
| Coefficient of consolidation (cν) | OED TX |
OED TX |
OED TX |
OED TX |
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| Permeability (k) | TXCH PSA |
TXCH PSA |
PTC TXCH (PTF) |
TXCH (PTF) (OED) |
TXCH (PTF) (OED) |
TXCH (PTF) (OED) |
| — = not applicable ( ) = partially applicable only; for details, see Section 5. Abbreviations of laboratory tests: BDD Bulk density determination DSS Direct simple shear test OED Oedometer test PTF Permeability test in the falling head permeameter PTC Permeability test in the constant head permeameter RS Ring shear (Ring shear box test) SB Translational shear box test SIT Strength index tests (normally performed in the preliminary phase only) PSA Particle size analysis TX Triaxial test TXCH Permeability constant head test in the triaxial cell (or flexible wall permeameter) |
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2.5 Controlling and monitoring
(1)P A number of checks and additional tests shall be made during the construction and execution of the project, when relevant, in order to check that the ground conditions agree with those determined in the design investigations and that the properties of the delivered construction materials and the construction works correspond to those presumed or specified.
NOTE See also EN 1997-1:2004, Section 4.
(2)P The following control measures shall be applied:
- check of ground profile when excavating;
- inspection of the bottom of the excavation.
(3) The following general control measures may be applied:
- measurements of groundwater level or pore pressures and their fluctuations;
- measurements of the behaviour of neighbouring constructions, services or civil engineering works;
- measurements of the behaviour of the actual construction.
NOTE Controlling and monitoring is of prime importance when the observational method is used (see EN 1997-1:2004, 2.7).
(4)P The results of the control measures shall be compiled, reported and checked against the design requirements. Decisions shall be taken based on these findings.
