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Final preparatory works for the wells have begun
Final preparatory works for the wells have begun
With the construction of six wells, long-term stability and safety of the portal area of tunnel T1 KP will be ensured. The photo shows the beginning of preparatory works for well V2 and the concreting of the edge beam on 16 previously installed piles, each 10 metres deep, which have ensured the stability of the steep slope of the Glinščica Valley.
Well V2 is located between the main and service tunnel tubes, has a diameter of 8 metres, and will be 30 metres deep, extending below the level of the Glinščica River.
During excavation works on tunnel T1 KP at the end of 2024, ground movement of the entire slope above the southern portal of the tunnel in the Glinščica Valley was detected. Based on an established comprehensive monitoring system of the area, it was determined that the portal zone is unstable, with increasing displacements of 0.5–1 mm per month. The largest measured displacements in the area of the Glinščica viaduct abutment reached 6 cm, while in the portal area above the service tube of tunnel T1—where movements are most pronounced—displacements reached up to 20 cm.
Based on structural analyses, a comprehensive stabilisation method was selected, involving the construction of six shafts and numerous other measures to ensure long-term stability and safety during the operational phase of the railway line. The following measures have already been implemented: installation of piles beneath the gallery between the main tunnel T1 KP tube and the Glinščica viaduct, installation of additional geotechnical anchors and a reinforced concrete beam, adaptation of the retaining structure’s back wall, and replacement of bearings and expansion joints on the Glinščica viaduct. In addition, the viaduct abutment was rehabilitated in a way that restores the originally designed structural movements.
