The use of sheet pile walls as permanent external walls for underground structures represents an effective solution for ensuring required stiffness and protection against groundwater. Sheet pile walls can withstand significant lateral loads while simultaneously preventing collapse of surrounding soil. They can be constructed from either steel or concrete, allowing selection of the optimal material based on specific project conditions.

Additionally, sheet pile enclosures provide high watertightness, which is crucial for protecting underground spaces from water infiltration—particularly in urban environments with potentially high groundwater levels. These structures can also improve acoustic performance of underground facilities by reducing noise penetration from external sources.