Chapter 14 — Laboratory & Field Testing Program¶

14.1 Start from the questions¶

A testing programme is not a shopping list of tests — it is driven by the design questions. Before specifying any test, ask:

This is the same "no question, no instrument" discipline as in monitoring (see the FHWA reference).

Parameter	Common tests
Index properties, classification	Sieve, hydrometer, Atterberg limits, water content
Compaction	Proctor (standard/modified), field density
Permeability	Constant/falling head, field pumping
Consolidation (\(C_c\), \(c_v\), \(\sigma'_p\))	Oedometer
Shear strength (\(c'\), \(\phi'\), \(c_u\))	Direct shear, triaxial (UU/CU/CD), vane
Stiffness (\(E\), \(G\))	Triaxial, pressuremeter, seismic, plate load
Liquefaction resistance	SPT/CPT with cyclic correlations

Index tests — cheap, fast, run on many samples to characterise variability.
Classification — one per stratum, at minimum.
Strength and consolidation — targeted at the critical layers identified from the site model.
Sample quality matters — disturbance changes strength and stiffness; use high-quality undisturbed samples for critical parameters.

In-situ tests (Chapter 12) for parameters where sampling is difficult or disturbance is a problem.
Groundwater monitoring with piezometers, over time to capture seasonal range.
Load tests where capacity is critical and expensive to get wrong.

Test results must be reduced to design parameters with the basis recorded:

report the range, not just a mean;
state the assumptions in interpretation;
cross-check laboratory and field values — large differences reveal problems;
compare with local experience and published correlations.

Let the design questions drive the testing programme.
Match each test to a parameter and to the analysis that uses it.
Use index tests widely and strength/consolidation tests on critical layers.
Sample quality is decisive for strength and stiffness.
Report the range and the basis, and cross-check lab against field.