Environmental Engineering Reference
In-Depth Information
FIGURE 2.55
Air track drilling in limestone for deep foundation investigation.
Figure 2.56
gives airtrack logs from an
investigation in limestone.
(15 to 30 m) depending on the uniformity of geologic conditions, the importance
of the structure, and the foundation type.
Dams are usually investigated on a grid of about 50 to 100 ft (15 to 30 m) spacing.
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Highway and railroad study programs depend on the adequacy of data obtained
during the geologic mapping phase as supplemented by geophysical and recon-
naissance studies (excavations, augers, probes, etc.), unless specified otherwise
by a highway department or other owner. A minimum program requires borings
in major cuts and fills, and at tunnel portals and all structure locations.
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In all cases, flexibility must be maintained and the program closely observed to
permit the investigation of irregular or unforeseen conditions as they appear.
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