마찰각

This table is a reprint of Table 3.11.5.3-1, AASHTO LRFD BDS, 4th ed, 2007

INTERFACE MATERIALS	FRICTION ANGLE, δ (°)
Mass concrete on the following foundation materials:  •Clean sound rock •Clean gravel, gravel-sand mixtures, coarse sand •Clean fine to medium sand, silty medium to coarse sand, silty or clayey gravel  •Clean fine sand, silty or clayey fine to medium sand •Fine sandy silt, nonplastic silt •Very stiff and hard residual or preconsolidated clay •Medium stiff and stiff clay and silty clay	35 29 to 31 24 to 29 19 to 24 17 to 19 22 to 26 17 to 19
Masonry on foundation materials has same friction factors.  Steel sheet piles against the following soils: • Clean gravel, gravel-sand mixtures, well-graded rock fill with spalls • Clean sand, silty sand-gravel mixture, single-size hard rock fill • Silty sand, gravel or sand mixed with silt or clay • Fine sandy silt, nonplastic silt	22 17 14 11
Formed or precast concrete or concrete sheet piling against the following soils: • Clean gravel, gravel-sand mixture, well-graded rock fill with spalls • Clean sand, silty sand-gravel mixture, single-size hard rock fill • Silty sand, gravel or sand mixed with silt or clay • Fine sandy silt, nonplastic silt	22 to 26 17 to 22 17 14
Various structural materials:  • Masonry on masonry, igneous and metamorphic rocks:      o dressed soft rock on dressed soft rock      o dressed hard rock on dressed soft rock      o dressed hard rock on dressed hard rock • Masonry on wood in direction of cross grain • Steel on steel at sheet pile interlocks	35 33 29 26 17