Which mechanical vulnerability was strategically exploited when using sapping during a siege?

💡 Explanation

Sapping relied on undermining walls, inducing localized soil liquefaction. The water content increases the pore water pressure, because that pressure becomes significant relative normal stress, therefore reducing effective stress, rather than global structural shear.

• Which structural failure increases in timber-framed windmills when grain dust accumulates excessively inside the mill housing?
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• Which risk increases when early cast-iron cannons experience internal defects during the gunpowder ignition?
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