Recent Experiences of Reinforced Soil Retaining Structures in China - Reinforced Soil Engineering: Advances in Research and Practice - page 170

Setting z ¼ x tan b in above equation, the stress on OB can be obtained;
then considering the balance of wedge on OB (see Fig. 11 ), the following
equation is obtained:

K a gj z ¼

tan 2 f
tan 2 f 2

2 tanf
tanb

X ¼ 1 þ Kgj z ð 5 Þ

where X ¼ horizontal pressure acting on the sleep slope OB, i.e., reinforce

required by stability of slope OB, while K ¼ horizontal pressure coefficient. Eq.

(5) shows that when b ¼ f, X ¼ 0; when f ¼ p/2, X ¼ K a gz, namely, active

earth pressure.

3.2.2 Prediction of Sliding Surface

Better accuracy of Eq. (5) indicates that wedge analysis of elasticity is applicable.
The same analytical methods are used for determining the potential sliding
surface of a reinforced slope. Putting reinforced X on the OB (see Fig. 11), based
on the balance of wedge BOZ, the stresses in the wedge are obtained. Substituting
the stresses to the following equation, the direction of principal stress s 1 can be
obtained:

2t xz
s x 2

tan 2a ðÞ¼2 ð 6 Þ

s z

¼

where a angle between direction of s 1 and x-axis.

Because the sliding surface is inclined at an angle

8 þ

f/2) to the
direction of the plane acted by s 1 , the sliding surface can be determined.

^ (45

3.2.3 Design Method

The horizontal earth pressure on the steep slope or wall determines the required
tensile strength and the spaces of reinforcements. The length of reinforcement
can be calculated based on the position of the sliding surface (Wang Zhao, 1993).

4 CASE HISTORIES

4.1 Retaining Wall with Height of 35.5Meters

A retaining wall reinforced by parawebs with a height of 35.5m is one of the
highest retaining walls in China. The wall is located in GuYi County for a main
highway from Xian to Baotou.