Non-in Situ Test Analysis of Reinforcement Construction Near Subway Tunnel

Triaxial mixing pile was used to reinforce the soil around the subway tunnel of Shanghai Metro Line 2. In order to test the influence of construction method on subway tunnel structure and optimize the design of construction parameters, non-in situ test research was carried out before construction. During the construction of triaxial mixing pile, the lateral displacement of deep soil in the range of 1.5~3.0 m from the center of pile wall was tested. The test results show that when triaxial mixing sinks to the design depth, the deformation of surrounding soil reaches the peak value. The deformation value begins to fall 3 hours after pile completion, and the deformation was basically stable at 1~2 mm at 64 hours after pile completion. The deformation depth was mainly in the shallow part, and the superposition influence of construction would lead to the downward movement of the deformation influence depth. This research could provide reference for similar projects.