Transmission And Substation Foundations - Technical Design Manual

SECTION 4: DESIGN METHODOLOGY

Evaluating Soil Properties for Design

OCR = 1

10

100

90

80

NC sands

70

30 Relative Density, D R (%) 40 50 60

OC sands

26 Different Series n = 677 data points

q T1 300.OCR 0.2

20

D R = 100

10

0

0

100

200

300

400

500

600

Normalized Tip Stress, q T1

Relationship Between Relative Density and CPT Normalized Tip Stress for Normally Consolidated (NC) and Overconsolidated (OC) Sands Figure 4-14

55

φ’ = arctan[0.1 + 0.38 log(q t /σ vo ’)]

50

45

40

Frankston Sand

35

Hokksund Sand Edgar Sand Ticino Sand

30

Effective Friction Angle, φ’ (deg)

Lone Star Sand

25

R&C (1983)

20

1000

10

100

Normalized Tip Stress, q t / σ vo ’

Relationship Between Friction Angle and CPTU Effective Tip Resistance Figure 4-15

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