Research on the Optimization of Deformation Control Technology for Ultra-Wide Diaphragm Walls in Deep Foundation Pits of Underground Stations in Water-Rich Soft Soil

This paper addresses the challenge of controlling deformation in ultra-wide diaphragm walls within deep foundation pits for underground stations in water-rich soft soil, proposing a systematic optimization technology framework. Based on the Nanmen Station metro project, a quantitative correlation model between diaphragm wall deformation response and construction parameters was established through computational analysis, on-site monitoring, and dynamic adjustment of construction parameters. The study reveals the coupled action mechanism of groundwater pressure, soil heterogeneity, and the segmented panel excavation sequence on wall deformation. Based on this, key control technologies were developed, including the reinforcement of the guide wall structure, graded control of the slurry mix ratio, and optimization of the trenching and panel installation sequence. Engineering verification shows that the optimized technology can reduce the maximum lateral deformation of the wall by 18.3% and narrow the fluctuation range of vertical displacement at the wall’s top to ±6.5mm, significantly enhancing the overall stability of the retaining system. The research findings provide a replicable collaborative deformation control paradigm for the construction of ultra-wide diaphragm walls in water-rich soft soil environments.