Which risk increases most when besieging Roman fortifications experience undermining failure?

💡 Explanation

When Roman fortifications undergo undermining failure, structural integrity is breached as tunnels weaken the foundations, causing localized wall collapses because of gravity and stress redistribution. Therefore, fortress walls are at risk, rather than catapult issues, demoralization, or well which involve orthogonal attack mechanisms.

• Which mechanism limited the maximum span of medieval timber-framed buildings before the advent of iron connectors?
• Which metallurgical outcome occurred when early steel production introduced manganese during iron smelting?
• Which effect limited the range of Roman torsion-powered siege engines, like ballistae, when targeting fortified walls?
• Which structural challenge did 18th-century shipbuilders overcome by implementing 'hogging trusses' during construction?
• Which risk increased in 16th-century fortress design by neglecting algebraic calculation of maximum cannon range?
• Which limitation affected early applications of algebra within water distribution systems described by Al-Karaji?