Subsurface exploration

DOE-STD-1022-94

soil-structure interaction, assessment of strain dependent soil dynamic modulus and damping characteristics

are needed. An appropriate site investigation program shall be developed in consultation with the

geotechnical engineering representative of the project team.

5.5.1.1 Subsurface exploration

Subsurface conditions shall be determined by means of borings, soundings, well logs, exploratory

excavations, sampling, geophysical methods (e.g., crosshole, downhole, and geophysical logging) that

adequately disclose soil and ground water conditions. Appropriate investigations shall be made to determine

the contribution of the subsurface soils and rocks to the loads imposed on the structures subjected to NPH.

The extent of subsurface investigations is dictated by the performance category of the facilities, by the

foundation requirements, and by the complexity of the anticipated subsurface conditions. For sites containing

facilities with SSCs in Performance Category 3 and 4, the QA requirements should be extended to retrieving,

transportation, handling and testing of soil samples. The locations and spacings of borings, soundings and

exploratory excavations shall be chosen to adequately define subsurface conditions. Subsurface explorations

shall be located to permit the construction of geological cross sections and soil profiles through foundations

of safety-related structures and other important locations at the site. Sufficient geophysical and geotechnical

data should be obtained to allow for reasonable assessments of representative soil profile and soil parameters

and their variabilities across the site.

5.5.1.2 Laboratory tests

A laboratory testing program shall be carried out to identify and classify the subsurface soils and rocks and

to determine their physical and engineering properties. For evaluation and design of DOE facilities with

SSCs in Performance Category 3 or 4, laboratory tests for both static and dynamic properties (e.g., shear

modulus, damping, liquefaction resistance, etc.,) are generally required. The dynamic property tests may

include cyclic triaxial tests, cyclic simple shear tests, cyclic torsional shear tests, and resonant column tests.

Both static and dynamic tests shall be conducted as recommended in American Society for Testing and

Materials (ASTM) standards or test procedures acceptable to the DOE. The ASTM specification numbers

for static and dynamic laboratory tests can be found in the annual books of ASTM Standards, Volume 04.08.

Examples of soil dynamic property and strength tests are shown in Table 1, Sufficient laboratory test data

should be obtained to allow for reasonable assessments of median values of soil properties and their potential

variability.