Which challenge complicated Roman roads constructed over unstable marshland terrain?

💡 Explanation

When roads were constructed on marshland, soil compression under the road's weight was significant because the wet soil had a high void ratio and low shear strength, leading to settling of the road surface. Therefore, settlement due to soil compression was the main problem, rather than cracking, deformation, or corrosion which imply temperature changes, freeze-thaw cycles, or salt solutions.

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