A Study on the Construction Optimization Technology for Deformation Control of Double-Pinned H-Beam Struts in a Long and Narrow Deep Foundation Pit in Water-Rich Soft Soil

Long and narrow deep foundation pit projects in water-rich soft soil areas face challenges such as difficulty in controlling construction deformation and high construction risks. As a new type of support structure, double-pinned H-beam struts possess advantages such as high stiffness, small deformation, and convenient construction, demonstrating promising application prospects in long and narrow deep foundation pit projects in water-rich soft soil. This study, taking the Nanmen Station metro foundation pit project as a case study, introduces the key technical points of the double-pinned H-beam strut construction technology. It systematically investigates the construction deformation control of these struts by integrating field monitoring methods and theoretical computational analysis. Deformation data of the double-pinned H-beam struts during the foundation pit excavation process were obtained through field monitoring, and their deformation patterns and safety conditions were analyzed. The displacement control effects of three support forms—no reinforced steel struts, single-pinned H-beam struts, and double-pinned H-beam struts—were compared using finite element simulation. The research results can provide a theoretical basis and technical reference for the design and construction of long and narrow deep foundation pit projects in water-rich soft soil areas.