Which risk increased when siege engineers of antiquity attempted to undermine castle walls past the 'angle of repose'?

💡 Explanation

When undermining castle walls beyond the angle of repose, the soil's shear strength becomes insufficient to support the overburden weight, leading to tunnel collapse due to gravity exceeding soil resistance. Therefore tunnel collapse risk increases, rather than explosions, flooding, or suffocation, which require different environmental conditions and extraction processes.

• Which navigational error grew when early 18th-century ships sailed westward lacking accurate longitude measurements?
• Which outcome occurred when Roman siege catapults launched projectiles over city walls at shallow angles?
• Which consequence resulted from thermal expansion impacting the accuracy of navigational sextants onboard 18th-century wooden ships?
• Which outcome resulted from over-tempering bloomery steel in medieval sword smithing?
• Which phenomenon allowed Alhazen to accurately trace light paths during experiment design?
• Which environmental risk increased in Post-Classic Mesoamerica due to intensive chinampa cultivation within limited lake systems?