Category

Description

q_c(MPa)
(c)

N
(d)

p₁(MPa)
(e)

Ep(MPa)
(f)

q_u(MPa)
(g)

V_s (m/s)
(h)

S₁

Rocky (a)

-

-

>5

>100

>10

≥800

S₂

Firm

>15

>50

>2

>20

>0.4

≥400-<800

S₃

Soft

1.5-15

10-50

1-2

5-20

0.1-0.4

≥200-<400

S₄

Very soft or presence of more than 3m of soft clay (b)

<1.5

<10

<1

<5

<0.1

≥100-<200