Abstract: With the popularization of urban rail transit, more and more deep excavation projects are carried out in urban areas. In the more developed cities, most of the strata are formed by alluvium near rivers. Under such geological conditions, the proposed construction is increasingly faced with the issues associated with historical building protection. By the scientific and comprehensive use of technical measures such as waler wall reinforcement, new composite bentonite and axial force controlled system, the deformation control of foundation excavation can be significantly improved and the impact of the construction on the environment can be reduced. This paper presents a metro station excavation in Nanjing area as an example. The paper adopts these technical measures as waler wall reinforcement, new compound bentonite, axial force controlled system, and scientific decompression and recharge as needed. All these parameters of the foundation excavation support construction were within the controllable range, and the comprehensive application of the above measures could better solve the concerns of the historical building preservations.

Key words: Rail Transit, Geological Conditions, Axial Force Controlled System, Historical Buildings