Which structural failure most likely occurred when segments of the Roman Servian Wall leaned outwards over time?

💡 Explanation

When facing stones are not tied or bonded to the backing stones, differential soil settling can cause one course of stones to settle farther than the adjacent course, thereby inducing outward leaning. Therefore differential soil settlement is most likely, rather than seismic or thermal effects, since these typically cause different stresses.

• Which risk increases when Roman road pavers used poorer quality aggregate materials during construction?
• Which mechanical interaction enabled early mechanical clocks (pre-1600s) to achieve stable oscillation despite variations in drive force?
• Which technique did medieval Islamic mathematicians employ when solving algebraic equations geometrically?
• Which outcome initially limited efficiency of early Newcomen steam engines despite their scale?
• Which navigational risk increased aboard 18th-century ships when chronometer escapement mechanisms suffered temperature-induced dimensional changes?
• Which iterative algebraic process did Al-Khwarizmi's method, 'al-jabr,' effectively apply to solve quadratic equations geometrically?