EARTH PRESSURE CHARTS FOR RETAINING WALLS.

Charts have been developed for estimating lateral earth pressures on retaining walls based on certain assumed soil properties of the backfill materials. These semi empirical methods represent a body of valuable experience and summarize much useful information. The charts given in Fig. 19.4 are meant to produce a design of retaining walls of heights not greater than 6 m. The charts have been developed for five types of backfill materials given in Table 19.1. The charts are applicable to the following categories of backfill surfaces. They are

1. The surface of the backfill is plane and carries no surcharge
2. The surface of the backfill rises on a slope from the crest of the wall to a level at some elevation above the crest.

The chart is drawn to represent a concrete wall but it may also be used for a reinforced soil wall. All the dimensions of the retaining walls are given in Fig. 19.4. The total horizontal and vertical pressures on the vertical section of A B of height H are expressed as

Values of Kh and Kv are plotted against slope angle Β in Fig. 19.4 and the ratio H1/H in Fig. 19.5.

Table 19.1 Types of backfill for retaining walls

Figure 19.4 Chart for estimating pressure of backfill against retaining walls
supporting backfills with a plane surface. (Terzaghi, Peck, and Mesri, 1996)

Figure 19.5 Chart for estimating pressure of backfill against retaining walls supporting backfills with a surface that slopesupward from the crest of the wall for limited distance and then becomes horizontal. (Terzaghi et al., 1996)