MJS reinforcement of foundation pits adjacent to existing stations and settlement analysis of surrounding buildings

During the construction of the transfer node at Waitan Bridge Station on Line 7 of Ningbo Rail Transit, it was recognized that the proximity of the new building to the existing Line 2 station, within a complex environment characterized by soft soil layers, posed a risk of excessive deformation to both the project structure and surrounding buildings. To address this concern, the MJS construction method was employed to reinforce the soil on the west side of the existing station, while closely monitoring nearby buildings. The monitoring results revealed an overall increase in settlement of surrounding buildings, with maximum settlement occurring primarily in corner areas within the influence range of foundation pit. Prior to excavation, deformation on the east side of the foundation pit—strengthened by MJS—was effectively controlled within −2 ~ 4 mm; meanwhile, deformation on its west side ranged from −5 ~ 7 mm. Post-excavation, deformations on both sides were managed within −6 ~ 4 mm. In comparison with pre-excavation increments in deformation levels around foundation pit—which remained significantly lower than a monitored control value set at 25 mm—it is evident that implementation of MJS construction method has effectively mitigated structural deformations in surrounding buildings and enhanced safety during foundation pit excavation. These findings can offer valuable insights for similar projects moving forward.