Permeability and its influence - Geotechnical Investigation and Design Tables - page 100

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The likely permeability for various joints features would havemost of the following
characteristics.

Table 8.19 Effect of joint characteristics on permeability.

Typical joint characteristics Permeability

m/s

Joint openness Filling Width Fractures

Open Sands and gravels 20 mm 3 interconnecting Joint sets 10 − 5 > ≥ >

Gapped Non plastic fines 2-20 mm 1 to 3 interconnecting Joint sets 10 − 5 to 10 − 7

Closed Plastic clays 2mm 1 Joint sets 10 − 7 < ≤ <

8.20 Lugeon tests in rock
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The Lugeon test (also know as a Packer Test) is a water pressure test, where a
section of the drill hole is isolated and water is pumped into that section until the
flow rate is constant.

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A Lugeon is defined as the water loss of 1 litre/minute/length of test section at an
effective pressure of 1MPa.

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10 − 7 m/s.

1 Lugeon ∼

Table 8.20 Indicative rock permeabilities from the lugeon test.

Lugeon Joint condition

1 Closed or no joints <

1-5 Small joint openings

5-50 Some open joints

50 Many open joints >