Which mechanism caused the eventual breaching of Roman fortifications during prolonged sieges, despite their advanced design?

💡 Explanation

When attackers employed undermining (siege mining), soil erosion weakens the foundations because soil displacement reduces load-bearing capacity, destabilizing the structural integrity over time. Therefore, collapse via undermining results, rather than direct collapse from ballista fire, ramp overrunning or ladder scaling whose effectiveness decreases with strong foundations.

• Which mechanical effect most directly improved navigational accuracy when John Harrison's marine chronometer experienced fluctuating temperatures?
• Which limitation constrained the pre-Columbian chinampa agricultural technique in Mesoamerica?
• Which critical risk increased when 18th-century ships began using iron ballast near navigation equipment?
• Which algebraic outcome resulted from Al-Khwarizmi's method of 'al-jabr' when solving quadratic equations involving geometric areas?
• Which degradation process limited axehead lifespan of early bronze axes in Mesopotamia following river water immersion?
• Which vulnerability critically undermined Roman siege towers during protracted sieges?