English：

In response to the complex surrounding environment, limited construction space, anddeformation control challenges faced by narrow space deep foundation excavation project, a zoning andsegmented combined support scheme is proposed based on the Baogang Primary School renovation andexpansion project in Shenzhen. Excavation is carried out in the soft soil area using soil nail walls andslope ratios. A waterproof curtain is formed around the foundation excavation by combining row piles withthree,axis mixing piles, and drilled interlocking piles are installed to improve the support stiffness,achieving foundation excavation construction safety. During the construction process, the speed limitinggrouting technology is used to control the construction rate of three,axis mixing pile, and quality of drilledinterlocking pile is ensured through casing drilling and verticality monitoring. At the same time, amonitoring system is deployed to collect real,time deformation data of support structures and surroundingbuildings. The research results indicate that the combined support system can effectively isolateconstruction disturbances, combined with real,time monitoring feedback mechanisms,while balancingsafety and economy.