




The project involves a cultural heritage building from the 1920s. The reinforcement and renovation included the complete removal of all internal load-bearing walls in the original basement to create a large-span underground space, and increasing the original basement height from approximately 2.4m to 6.26m. The overall renovation achieved the expansion of underground space and a comprehensive upgrade of the building's structural functions.
The project is an underground double-deck island station (partially three levels), forming an "L" shape in plan with the concurrently constructed Metro Line 6 station. The foundation pit has a complex surrounding environment, adjacent to tall buildings. Its transfer node is a large-section shaft-type deep foundation pit (44.5m×38.5m×26.0m) with strict deformation limits. The composite steel support technology for large-section shaft-type deep foundation pits was adopted.
The underground exhibition hall has two basement levels, with a "convex" shape in plan and a building area of approximately 25,000 m². The foundation depth is 17.00m. The company undertook the evaluation study on the impact of the underground exhibition hall on the foundations of surrounding buildings (structures) and on the overall foundation of the Palace Museum.
The project confirmed the current condition of the buildings and proposed control standards for differential settlement of their foundations during construction. Based on the assessment report, the metro construction eliminated the isolation piles and shifted the right tunnel outward. The maximum settlement of the buildings was 7.3mm, and the normal use of the residential buildings was not affected.
The project delineated the key impact zones of the metro tunnel, confirmed and classified the current conditions of buildings within the key impact zones, and finally proposed control standards for differential settlement of various building foundations during construction.