how do they maintain the integrity of its structure?
UNANSWERABLE
where is the largest dam in the world located It spans the Yangtze River by the town of Sandouping, in Yiling District, Yichang, Hubei province, central China, downstream of the Three Gorges. has it experienced any natural calamity? Yes, there are frequent major landslides and river  flooding.
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Three Gorges Dam [SEP] Structural integrity
Days after the first filling of the reservoir, around 80 hairline cracks were observed in the dam's structure. However, 163,000 concrete units of the Three Gorges Dam all passed quality testing and the deformation was within design limits. An experts group gave the project overall a good quality rating. A German-based hydraulic engineer, Wang Weiluo, who has criticized the Three Gorges Dam project for years, claims that financial abuse by related governmental bureaucrats and rushed construction work have led to structural weaknesses that may cause the dam to fail through leakages in the foundation. In 2019, photographs on Google Earth, in which photographic distortion appeared to show severe deformation of the structure, led to rumors on social media of the dam's potential collapse.