GEOG 1280 Lecture Notes - Lecture 19: Frost Heaving, Frank Slide, Crystal Growth
Document Summary
Clay minerals: house of cards structure held together by salts. After the dissolution of salts and compaction the structure is stronger but can fail very easily. On a flat surface the force of gravity acts downward perpendicular to the slope. On a slope, the force of gravity can be resolved into two components: a component acting perpendicular to the slope gp and a component acting tangential to the slope gt. Tangential component of gravity causes a shear stress parallel to the slope that pulls the object in the down-slope. On steeper slopes, the shear stress or tangential component of gravity, increases and the perpendicular component of gravity, decreases. Dry sand: angle of repose is the steepest angle at which a pile of unconsolidated grains remain stable, controlled by the frictional contact between the grains. Dry materials the angle increases with increasing grain size, usually between 30 and 37 degrees.