Abstract: There are special functional requirements for the grounding system during the construction of linear tunnel-type underground precision experimental housing projects. A case study is conducted on the tunnel-type precision experimental housing project of Moganshan AI Base in Zhejiang(China) and WHDK project in Conghua(China), two schemes of common grounding systems with separate grounding trunk and grounding terminal and signal independent grounding system are proposed for precision test instruments and equipment in test space based on functional grounding, protective grounding, local horizontal equipotential grid format signal grounding, independent grounding trunks for precision experimental instruments and equipment, grounding terminals, and potential adjustment facilities between different ground grids. The applicability, advantages and disadvantages of these two schemes are analyzed, and the corresponding solutions and strengthening measures are given for the problems that may exist in each scheme. It is concluded that scheme 1 is recommended under normal circumstances, and scheme 2 can be considered when there is a clear and necessary demand for signal grounding of precision test instruments and equipment.

Key words: underground precision experimental rooms in form of linear tunnels, grounding system, potential difference