Then, you should collect some information about the forms of earth seal in imperial tombs, because I think this aspect may be directly related to your topic, because it introduces several important forms in the development of imperial tombs in China, such as the earth seal tomb on tombs, which probably appeared in the late Yin Dynasty and early Zhou Dynasty and is still a burial style used by ordinary people. On the other hand, simply speaking, the underground palace is built with loess layer by layer. It prevailed in Qin and Han dynasties. Here, I would like to mention the Mausoleum of the First Qin Emperor and the Mausoleum of the Fifth Emperor of the Han Dynasty, because their mausoleums are sealed with earth. In addition, there are mountains for the mausoleum, Baocheng Baoding and so on.
After understanding these main forms, we should also understand the different mausoleum buildings that appear in various tombs. Here, we need to carefully consider those places that are designed very high. General buildings on the ground are mainly composed of three parts: sacrificial area, Shinto and tomb protection.
Then the underground building of the mausoleum, from soil cave tomb to the wooden tomb and then to the underground palace built of brick and stone, developed in three stages.
When you understand this knowledge, you need some examples to help you interpret it, such as imperial tombs, including Qin Shihuang Mausoleum, Nine Mausoleums of the Western Han Dynasty, Tombs of Tibetan Kings and the Second Mausoleum of the Southern Tang Dynasty. You need to collect information yourself, because there are many, so I won't say more. In these examples, the overall layout, form and design of the mausoleum are introduced in detail, which should be helpful to your project.
There is a lot of knowledge about the mausoleum, but I just gave you a brief introduction. You'd better choose some books about traditional architecture and traditional mausoleum architecture in China, which introduce these knowledge in detail. These books are usually found in the school library. There are liberal arts and science, so it's best to check them all when inquiring.