First, there are sand and stones in the soil of Qing Dongling.
Yongzheng originally intended to build a mausoleum for himself in the Qing Dongling, and did not intend to find another place. He ordered people to investigate the Mausoleum of the Eastern Qing Dynasty, and decided to build the Mausoleum in chao yang shan, Jiu Feng, where even the timber and stones of the Mausoleum were transported.
When the Yongzheng Tomb was ready to start construction, in order to ensure foolproof, the Minister of Industry, who was in charge of the tomb construction, once again made a field survey of the geology of chao yang shan, Jiu Feng. But this survey made them find that the soil here contains sand and gravel, which they think is easy to seep and is not suitable for building graves.
After listening to the ministers' reports, Yongzheng also began to worry that if a mausoleum was built here, his coffin would soak in the water after the underground palace flooded, and it was himself who suffered, so he gave up building a mausoleum in the Qing Dongling.
Second, Yongzheng's superstition of Feng Shui.
The ancients paid great attention to geomantic omen in the location of tombs, especially emperors like Yongzheng who were obsessed with alchemy, and they believed in geomantic omen.
When chao yang shan, Jiu Feng was preparing to build a mausoleum, Yongzheng sent ministers who were proficient in geomantic omen to visit here, but after some investigation, these ministers agreed that chao yang shan, Jiu Feng was a good place, but it was not perfect.
Yongzheng wanted to build a mausoleum in an excellent land of geomantic omen and to continue his majesty after his death. So Yongzheng ordered his ministers to find a new place for him to be permanently happy. At the suggestion of ministers, he finally decided that the mausoleum was in Taining Mountain, which is now the Qing Xiling Mausoleum.