Underground substations are generally built in urban areas with tight land and dense surrounding buildings

with deep burial depth and high waterproof requirements

and the composite wall or laminated wall combined with diaphragm wall and interior wall are used for peripheral protection. The laminated wall technology is widely used in existing underground substation projects

but due to its own limitations

it cannot meet the requirements of General Code for Waterproofing of Building and Municipal Engineering for first level waterproofing. This article compares and analyzes the laminated wall and composite wall schemes in 110 kV Gansu underground substation in Shanghai

and conducts stress and economic analysis on different thickness combinations of interior walls and diaphragm wall. The results show that when the composite wall scheme is adopted

the bending moment of the interior wall is smaller

so that more economic reinforcement can be obtained

and the requirements of structural safety and crack control can be met with better economy.