Recent Experiences of Reinforced Soil Retaining Structures in China - Reinforced Soil Engineering: Advances in Research and Practice - page 173

Only the active earth pressure on the facing plate is introduced here.
Because of symmetry, the active earth pressure of every facing plate can be
estimated by Rankine's theory.

=

gz 2 K a = Btg u

E a ¼ 2 when z # 2 ð 7 Þ

=

z 2 Btg u

2

Btg u E a ¼ g ð 2 ð z 2 ð Þ= 2 Þ Þ K a = 2 when 2 , z # H ð 8 Þ

Equation (8) can be simplified to

= Þ

K a tg u =

B 2 tg u E a ¼ g B Z 2 4 2 ð 9 Þ

where g ¼ unit weight of soil, K a ¼ active earth pressure coefficient, B ¼ width

of retaining structure, u internal friction angle.

The distribution of earth pressure on the facing can be obtained by the
differential of Eqs. (7) and (9):

¼ 45 8 þ f/2, f ¼

Btg u e a ¼ gzK a when z # ð Þ= 2 ð 10 Þ

gBtg u K a =

=

Btg u e a ¼ 2 when 2 , z # H ð 11 Þ

Equation (11) shows that the e a is a constant and equal to e a from Eq. (10)
when z (Btg u )/2. The e a is much less than that in direct proportion to z, so that

the required tensile strength of reinforcement is much lower.
A reinforced retaining wall with two opposite facing plates is on the bank
of the YaLu River (Fig. 13). The maximum height of the wall is 6m. The
thickness of the concrete plate is 120mm, behind which there are sand cushions

¼

Figure 13 Protection of bank of YaLu River.