STABILITY OF EARTH-RETAINING STRUCTURES - Introduction to Soft Soil Geotechnique: Content, Context and Application - page 184

In this case, the water in the crack adds to the active thrust for 36%. When
retaining walls do not fulfil stability requirements, it is usually not because the
earth pressures are inadequate, but rather because often drainage measures are (or
become) ineffective.

application 11.2
Consider a stiff combi-wall which forms the side of a building pit; its length is
17 m (see Fig 11.11). A strut with horizontal force F is pushing against this wall,
every 5m (the strut's interspace distance). Sunshine on this strut may cause
extension, which can increase the force drastically. Sketch the distribution of
induced horizontal stresses on the wall. Calculate the maximum value of F . The
soil weight is = 35 o , c = 0.

Advice: Assume rotation point at B. Find F by moment around B and find F
from the horizontal equilibrium. The answers may differ slightly; in fact the
rotation point is a little higher.

= 18 kN/m 3 ,

2m 2m

F F

10m 10m

d d 17m 17m

B B

e e

Figure 11.11

application 11.3
Does the method used in application 11.2 lead to an upper or lower limit?

2m 2m 2m 2m 2m 2m 2m 2m

F F F F

F F F F

10m 10m 10m 10m 10m 10m 8m 8m

17m 17m 17m 14m 17m 17m 17m 14m

d d d d d d d d d d d d d

B B B B B B B B B B B B B

e e e e e e e e e e e e e

Figure 11.12