Sheet piling is a type of earth retention system used in excavations to prevent soil collapse. Reasons include:

D. When the natural soil slope is too steep to remain stable, sheet piling acts as a vertical barrier.

E. When soil cannot support itself during excavation, sheet piles provide lateral support.

F. When excavation is adjacent to a property line or existing structure and adjacent soil must not be disturbed.

Options A (grade beam support), B (raked shoring), and C (pile cap support) are not typical or primary uses of sheet piling.