A cantilever retaining wall is shown in Figure 9.27.

The backfill is granular soil. The wall geometry and the characteristics

of the backfill and foundation soils are shown in the figure. Under the

design earthquake, the horizontal acceleration coefficient is 0.2, and

the vertical acceleration coefficient is 0.05. The external friction angle

between the granular backfill and the wall is two-thirds of the internal

friction angle.

(1) Calculate the total static earth force behind the retaining wall and

determine the location and direction of the resultant force.

(2) Calculate the total dynamic earth force under the design earth-

quake and determine its point of application.