15 August 2002
Usage. Borings determine soil properties and ground water levels for
establishing cutoff elevations for piles supporting special structures. Borings can also
be used for conducting permeability and pumping tests, if necessary. Refer to DM-7.01
Soil Mechanics for criteria for pumping and permeability field tests and laboratory
Pile Driving Records. Consult previous pile driving records for applicable
information. Supplement these records, if necessary, by new test pile data, especially
in areas where appurtenant foundation structures may be used for track supports,
capstan foundations, and similar facilities. Pile driving information and equipment are
discussed in DM-7.02 Foundations and Earth Structures.
Laboratory Tests and Soil Analyses. Laboratory tests applicable to
soils are generally necessary. For application and interpretation of such tests refer to
Bearing Capacities of Soils. Make tests for bearing capacity appropriate
to the types of applied loading in accordance with provisions of DM-7.01 Soil
Mechanics. For designs of drydock cross-sections, especially those with thin floors, the
elastic modulus of material under a floor is important.
Foundation Materials. Many types of foundation materials may be
encountered in a site, and almost all may be utilized for supporting a drydock.
Effect on Structures. This material variability, however, results in a
number of structural types from which a selection must be made. For selection of
structural types affected by foundation conditions, refer to Chapter 4.
Soils. Types of soil which may be encountered, and upon which drydocks
may be founded, include soft and hard rock, hardpans and shales, sand and/or gravel,
soft and hard clay, marl, soft and hard mud, and certain types of coral. Extremely
cavernous coral, through which water flows in such quantities as to preclude even
grouting, cannot be used as a site support.