Soil mechanical properties

The data given below covers the generally accepted values for soil characterization. It does not dispense with actual site or laboratory measurements.

The values indicated in the table are those generally accepted for soil characterization. They cannot replace actual site or laboratory measurements.

 

Φ: Angle of internal friction (in degrees)
γ: Density (in t/m3)

Average characteristics of commonly encountered soils

Type of ground

Dry/Wet

Submerged

Φ

γ

Φ

γ

degrees

t/m3

degrees

t/m3
Fragmented rock

40°

2

35°

1.1
Gravel, sands

35°

1.9

30°

1.1
Sand/gravel
Silts/clays

30°

2

25°

1.1
Silts/clays

25°

1,9

15°

1
Humus organic/clays/silts

15°

1.8

no mean characteristics

 

(a) As per Fascicule 70
(b) Classification as per NF P 11-300/GTR (Road works guide)
(c) Ip = Plasticity index

Average values for backfill modulus of reaction E (a)

Type of soil used for backfill

Backfill module of reaction E
Description

Classification
(b)

Degree of compaction (Proctor)
   

Non compacted
(80 à 85 %)

Controlled compaction
(85 à 90 %)

Controlled
and checked compaction
> 90 %

Mpa

Mpa

Mpa
Clean or slightly silty sand and gravel (elements < 50 mm)

B1 B2 B3 D1 D2

0.7

2.0

5.0
Silty or medium clay sand and gravel

B4 B5

0.6

1.2

3.0
Flint or millstone clay. Rubble, moraine, eroded rock, coarse alluvium with high percentage of fines

C1 C2
with Dmax<250 mm

0.5

1.0

2.5
Loam, fine sand, gravel, more or less plastic marl (Ip < 50)

A1 A2 A3 B6

< 0.3

0.6

0.6
Unstable rock: chalk, sandstone, schist. Composite soils (flint and millstone clay, moraine, eroded rock, coarse alluvium with elements that may exceed 50° mm

D3
C1 C2
with Dmax>250 mm
R13 R23 R34 R43

0.7

2.0

5.0