【正文】 granular materials with conspicuous clay content。 or residual soil with stone。 ? fine silty sand。 ? soft or very soft clay。 ? coarsegrained soil of low permeability, owing to admixture of particles of silt size。 anic silt。 c. passive earth pressure (the earth pressure exerted on the wall when the wall moves toward the soil). (2) A retaining wall must a. be able to resist sliding along the base, b. be able to resist overturning, and c. not introduce a contact pressure on the foundation soil beneath the base of the wall that exceeds the allowable bearing pressure of the foundation soil. 4 Sunday, August 14, 2022 Retaining Walls II. * Types of backfill materials for retaining walls ? coarsegrained soil without admixture of fine soil particles, very freedraining (clean sand, gravel, or broken stone)。 or soft silty clay。 3 Sunday, August 14, 2022 Retaining Walls b. active earth pressure (the earth pressure exerted on the wall, when the wall moves away from the backfill)。 ? medium of stiff clay that may be placed in such a way that a negligible amount of water will enter the spaces between the chunks during floods or heavy rains. 5 Sunday, August 14, 2022 Retaining Walls III. Stability Analysis 1. *Movement of retaining walls: horizontally (by sliding), vertically (by excessive settlement and /or bearing capacity failure of the foundation soil), and by rotation (by overturning). 2. The checks for sliding and for overturning hark back to t