Answer:
Cultural and ethnic integration.
Explanation:
Cultural integration is a process of cultural exchange which results in groups of people assuming and practicing the beliefs of other culture without sacrificing her own cultural attributes.
Ethnic integration involves social process by which different ethnics continue to interact resulting in ethnic identity of the participants.
China has about 56 ethnic tribes with about 55 minorities and 1 major tribe.
In the question, expansion through conquest is not the major concern of the Chinese governments but rather intergration of various ethnic and cultural groups within its territories.