Case Study of Rainwater Treatment System in a Large Urban Underground Space Complex Project in Xi’an China

Rational utilization and development of underground space, orderly arrangement of multiple functions in underground space, and forming underground complex system, is one of the effective ways to alleviate the contradiction of land resource shortage, and also one of the ways of sustainable development of green buildings. In the underground space complex project, the drainage problem is undoubtedly a very important aspect. Under geological conditions of collapsible loess, rainwater infiltration can easily lead to structural damage of collapsible loess and cause significant deformation of underground complex project. Therefore, how to collect and recycle the infiltration rainwater efficiently and safely is not only crucial for alleviating urban waterlogging, weakening surface water pollution, and stabilizing underground complex project, but also in line with the sustainable development concept of sponge city. Based on the Xi'an Happiness Forest Belt construction project, the rainwater treatment system has been optimized from design to construction. It can not only improve the rainwater treatment efficiency, but also better control the structure deformations caused by the collapsible loess damage caused by the rainwater infiltration processes in the construction and future operation stages.