For the online event join by clicking here at 5.55pm on 26 June

From the Owner’s Engineer perspective

The Snowy 2.0 project is a major pumped-storage expansion of the Snowy Mountains hydropower scheme, which forms a vital part of Australia’s energy transition towards a low-emissions future. The project will substantially increase the existing scheme’s capacity, adding 2200 MW of energy generation capacity and large-scale energy storage of 350,000 MW hours. At full capacity, Snowy 2.0 could operate for almost seven days without recharge pumping, providing deep energy storage necessary to underpin increasing wind and solar generation.

Not unlike the existing scheme, the Snowy 2.0 project involves substantial underground works, both in terms of scale and complexity. The key elements include 33km of TBM-driven tunnels, 10km of D&B tunnels, three shafts, and a large power station cavern complex located 750m underground.

This Technical Session will provide an overview of the Snowy 2.0 project, along with an update on the delivery of key underground elements. Following this, a deeper dive will be provided into elements of the geotechnical approach to the delivery of the underground power station cavern complex.

The Snowy 2.0 caverns are amongst the largest and deepest in the world and are being delivered with a highly observational approach, in which design predictions are continually reviewed against actual ground behaviour and support performance during construction.

In support of this approach, the project has developed a comprehensive 3D ground model that spans not only the caverns but also the surrounding network of tunnels.

Learning outcomes

• Snowy 2.0 project update

• Cavern excavation using an observational approach

• Cavern 3D geological model

Timings

5.00 pm – 6.00 pm Networking (Refreshments and drinks will be served)

6.00 pm – 7.00 pm Presentation

Speakers

Kara Stariha

Associate Geotechnical Engineer, SMEC

Kara Stariha has eleven years’ experience in a variety of civil, tunnelling, dams and hydropower projects in NSW, ACT and internationally. She has worked on all phases of project development, from feasibility studies and site investigations to design and construction phase supervision. Kara’s primary interest is in ground characterisation, rock mechanics, tunnelling, and the use of remote sensing in assessing the stability of rock slopes. She is experienced in guiding the technical implementation of risk-sharing contractual mechanisms (GBR), particularly as applied to tunnelling projects in complex geological environments.

Working on the Owner’s team for Snowy Hydro 2.0 since 2018, Kara has undertaken several roles relating to geotechnical engineering and ground classification throughout her time on the project. In the feasibility and reference design stages, Kara worked on the site investigations planning and execution, and in the geological and geotechnical interpretation and parametrisation along the tunnel alignments for input into the GIR and GBR. After taking a break from S2.0 in 2019 to complete her masters in Graz, Austria, Kara returned to S2.0 in 2021 as tunnelling commenced. At this time, S2.0 utilised a contractual risk share mechanism in the form of a Geotechnical Baseline Report (GBR).

Until 2023 Kara led the collection and assessment of incoming data and the application of this to assign conditions in accordance with the GBR. Kara now leads the Ground Model team, taking a higher-level approach to interpretation, modelling, and geological risk management. The team collects and interprets geological and geotechnical information, developing a model to inform Snowy Hydro of potential geological risks and tying this into the broader project risk assessments. This allows informed feedback to be provided to the contractor and assists Snowy Hydro in making key decisions around construction methodologies and forward investigations. Kara has driven the commencement of regular discussions with the contractor and designer on upcoming geotechnical and geological risks, allowing all parties to propose and agree on appropriate mitigation measures.

Ben Chapman

Tunnels and Geotech Lead – Snowy 2.0, SMEC

Ben is a Senior Associate Civil Engineer with 15 years’ experience in the design and delivery of tunnels and underground structures for a range of road, rail, water, and hydropower projects. Ben’s expertise relates to both structural and geotechnical engineering, covering all stages of project delivery, from planning and design to on-site construction and maintenance.

Currently, Ben is seconded to Snowy Hydro from SMEC Australia, where he has maintained a key involvement in the Snowy 2.0 project since the feasibility study initially commenced in 2017. Initially commencing as a Senior Tunnel Engineer, Ben was responsible for the coordination and design of the primary support systems and final linings for the tunnels, shafts, and caverns. He then continued a similar role in the subsequent reference design phase, with additional involvement in the preparation and negotiation of the Geotechnical Baseline Report (GBR), Employer’s Requirements and geotechnical risks register.

Since the award of the main Snowy 2.0 construction contract in 2019, Ben has been the Tunnels, Caverns and Geotechnical Discipline Lead and GBR Manager for the Snowy 2.0 Owner’s team. In this capacity, Ben leads a multi-disciplinary team of tunnel and geotechnical engineers and geologists in the review of detailed design and construction documentation for the projects’ substantial underground works. Ben also leads the team administering the GBR for the project, which is based on the principles of the recent FIDIC Emerald Book and is the first of its kind to be implemented in Australia.

In this capacity, Ben is responsible for the development and implementation of geotechnical classification systems and associated GBR management plans for conventional and TBM excavations. This allows for actual ground conditions to be assessed against the GBR baseline conditions and subsequent adjustment of time and cost to be applied in accordance with the contract.

The ATS Victorian Chapter and ICE Australia co-host the seminar. This event is sponsored by SMEC, the Owner’s engineer of the project.