Snowy 2.0
Project Snowy 2.0, Australia
Project Snowy 2.0, Australia
Early works for Snowy 2.0 started in May 2019 at the main Lobs Hole construction site. Major earthworks were carried out for the main access tunnel (MAT) portal and in recent months, a TBM cradle was built. It is here that tunnelling for Snowy 2.0 is anticipated to begin in late December. The 142m-long, 11m diameter CREG machine is initially scheduled to bore the MAT into the power station complex.
The TBM due to commence operation has been supplied by CREG and will bore the 2.7km MAT. At the completion of this drive, the machine will be dismantled and reassembled near the downstream reservoir to bore the 6.0km tailrace tunnel back towards the power station complex. The challenges faced by this machine are mainly associated with the anticipated ground conditions. The MAT reaches a maximum depth of approximately 750m, and therefore has potential for experiencing stress-induced ground behaviours. To address this, the TBM has been designed with reserve thrust and torque capacity, tapered shields and the ability to over-excavate. The drive also has the potential for experiencing high groundwater inflows, a risk which is exacerbated given the downward drive direction. To address these challenges, the TBM has extensive probe drilling and pre-grouting capabilities, in addition to substantial dewatering pump capacity.