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Building Design and Construction Handbook - Merritt - Ventech!

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TABLE 6.3 Boring, Core Drilling, Sampling, <strong>and</strong> Other Exploratory Techniques* (Continued)<br />

6.11<br />

Method<br />

(1)<br />

Procedure<br />

(2)<br />

Borehole camera Inside of core hole viewed<br />

by circular photograph or<br />

scan<br />

Pits <strong>and</strong> trenches Pit or trench excavated to<br />

expose soils <strong>and</strong> rocks<br />

Rotary or cable tool well<br />

drill<br />

Percussion drilling (jack<br />

hammer or air track)<br />

Toothed cutter rotated or<br />

chisel bit pounded <strong>and</strong><br />

churned<br />

Impact drill used; cuttings<br />

removed by compressed<br />

air<br />

Type of sample<br />

(3)<br />

Applications<br />

(4)<br />

Visual representation To examine stratification,<br />

fractures, <strong>and</strong> cavities in<br />

hole walls<br />

Chunks cut from walls of<br />

trench; size not limited<br />

To determine structure of<br />

complex formations; to<br />

obtain samples of thin<br />

critical seams such as<br />

failure surface<br />

Ground To penetrate boulders, coarse<br />

gravel; to identify<br />

hardness from drilling<br />

rates<br />

Rock dust To locate rock, soft seams,<br />

or cavities in sound rock<br />

* Reprinted with permission from ‘‘L<strong>and</strong>slides: Analysis <strong>and</strong> Control, Special Report 176,’’ Copyright 1978 by the<br />

National Academy of Sciences. Courtesy of the National Academy Press, Washington, D.C.<br />

Source: G. F. Sowers <strong>and</strong> D. L. Royster, ‘‘Field Investigation,’’ ch. 4 of ‘‘L<strong>and</strong>slides: Analysis <strong>and</strong> Control,<br />

Special Report 176,’’ ed. R. L. Schuster <strong>and</strong> R. J. Krizek, National Academy of Sciences, Washington, DC.<br />

Limitations<br />

(5)<br />

Best above water table or<br />

when hole can be<br />

stabilized by clear water<br />

Moving excavation<br />

equipment to site,<br />

stabilizing excavation<br />

walls, <strong>and</strong> controlling<br />

groundwater may be<br />

difficult<br />

Identifying soils or rocks<br />

difficult<br />

Drill becomes plugged by<br />

wet soil

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