Hydraulic Structures: Fourth Edition

Table 2.6 Indicative engineering properties for compacted earthfills (compare with Table 2.3)Fill type

Compaction

Shear strength

Coefficient of

Coefficient of

Drainage

(BS 5930)

characteristics

(effective stress)

compressibility, m

v

horizontal characteristics

(

10

4

m

2 kN

1

)

permeability,

(relief of u

)w

Unit weight,

Water

Cohesion, c



Friction,



kh

(ms

1

)

d max

(kN m

3

)w

opt

(%) (kN m

2

)

(degrees)

Gravels

18–22

05–10



0

35–40

0.1–1.0

10

3

–10

5

excellent

(GW–GC)Sands

16–20

10–20



0

35–40

0.5–1.5

10

4

–10

6

good

→

fair

(SW–SP)Silts

16–20

15–30



10

25–35

0.5–2.5

10

5

–10

8

fair

→

poor

(ML–MH)Clays

16–21

15–30



20

20–30

0.5–3.0

10

7

–10

10

very poor

→

impervious

(CL–CH)Crushed

17–21

N/A



0

40–55

N/A

10

1

–10

2

free-draining:

rockfill (2–600 mm

excellent

size range)Crushed rockfill is shown here for comparative purposes only – refer to Section 2.9.