Securing of tunnel driving operations against unconsolidated rock and rubble sliding down and when breaking through fault zones
Umbrella injection is a special case in rock mass stabilization. Especially with unstable rock strata in the back, a protective shield is put into place to prevent uncontrolled rock falls and smaller rocks from falling.
This type of tunnel stabilization during the tunneling process is mostly carried out using self-drilling injection lances in combination with
- PU resins
- often in double shields, initially using foaming materials
- for sealing strata against inflowing water
- Silicate resins, especially for voids and fissures
If a resin injection is not sufficient, anchor rock bolts can be installed to increase the load-bearing capacity and stability. Umbrella injection is a special measure in pre-excavation grouting and is frequently used for rock mass stabilization in the back.