2019 Volume 75 Issue 2 Pages I_30-I_40
Sumidagawa Sewer Trunk Line 3rd Project, which Tokyo Metropolitan Bureau of Sewerage ordered, was aimed to expand the middle part of the existing TBM tunnel by using large-scale radial ground freezing. We carried out the analysis of the influence of the ground freezing based on various monitoring data including ground deformation. As a result, we gained a trend regarding to formation of frozen soil, which actual uplift within the freezing ground is almost equal to frost heaving predicted by the general method called “Calculation method of 3D heaving deformation”. On the other hand, we also gained another trend which actual uplift on the ground is lower than the prediction due to the consolidation of soft clay in the unfrozen ground caused by the inflation pressure of the frozen soil. Furthermore, we adopted radial heating pipes and injection of cement-bentonite to the outside of the frozen soil, and confirmed their high suppression effect against the ground deformation.
