Once operational in 2020, the Xinjiang Fukang Pumped Storage Power Station in Western China, will supply hydropower energy to the major urban centres of the Xinjiang Changji Hui Autonomous Prefecture, delivering clean renewable energy to nearly 50,000 residents. Global multi-disciplinary geoengineering company, GEODATA Engineering SpA, was assigned by project manager, Northwest Engineering Corporation Limited, to provide technical consultancy and advisory services at the design stage for the excavation of the main powerhouse cavern.

GEODATA used Seequent 3D geological modelling solution Leapfrog Works to assess the geological risk, verify the stability of the support system and communicate that risk to stakeholders. Leapfrog Works is a fast and dynamic 3D subsurface modelling solution specifically designed for the Civil Engineering and Environmental industries. With Leapfrog Works, geological models can be easily combined with industry designs and flow models to give better insight and understanding.

GEODATA’s International Geoengineering Experts comment, “Leapfrog Works allowed us to very positively tackle the many challenges of this project. We were able to effectively present and analyse a huge mass of data alongside volumes of designed works and predict volumes to be excavated. Being able to rapidly visualise the geological elements, the designed works, and geomechanical information in 3D, was particularly helpful and had a great impact on the project. This 3D visualisation aided our understanding giving us clarity, and meant we were able to communicate with confidence.”

Power House Situation Beneath Steep Topography

At the beginning of 2018 GEODATA was assigned by Northwest Engineering Corporation Limited to provide technical consultancy at the detailed design work phase for the cavern complex. Their work commenced in May with GEODATA’s initial site visit and culminated in their final report release in October 2018. Leapfrog Works was used for geological modelling throughout this period.

GEODATA’s objective was to validate and if needed update the design of the proposed cavern support system, and ensure that it took into account the best understanding of the subsurface conditions that could be expected during the excavation and construction.

This meant evaluation of all available data regarding the geological setting as well as all available data regarding the excavation and support design to create a reference geological and geomechanical 3D model for the project. The creation of the 3D model allowed GEODATA to perform numerical analysis to evaluate the proposed support system and identify possible or necessary changes as well as specify the monitoring strategy.

Seequent’s civil engineering solution, Leapfrog Works, was chosen to give the best representation of geological and geomechanical data for the underground construction of the Power Station.

A significant challenge on this project was how to effectively combine and present the huge mass of data available from very different sources, whilecommunicating the subsurface conditions in a tight time frame. The types of data used included:

  • Borehole data, such as lithology, Geological Strength Index (GSI) and Rock Mass Rating (RMR) data.
  • Structural survey data taken from the adits (access tunnels) to the cavern, which was used to interpret faults and joints.
  • Engineering Design data for the three power station caverns, the penstock, safety access, tunnel access and the adits.
  • Topographical data.
Rock Mass Rating (Rmr) And Faults At Powerhouse Caverns. Note: Only Two Faults Are Visible For Simplicity

Using Leapfrog Works, GEODATA experts were able to present and analyse a large volume of data including geostructural information in combination with the designed works to calculate excavation volumes of different rock types. Leapfrog Works’ dynamic 3D modelling also enabled GEODATA
to readily compare 3D surfaces of faults with geomechanics indexes (RMR and GSI). The ability to visualise all of the data in 3D alongside the designed works (such as the caverns) was important to the success of the project. Being able to readily compare scenarios also allowed a more qualitative geological interpretation to be rapidly incorporated into the workflow.

A PhD Geologist from the GEODATA team commented “Leapfrog Works’ unique framework for heterogeneous information let us bring together data that normally would require different processing environments. This adaptability was a real benefit on this project”

Pat McLarin, Seequent Civil & Environmental Product Manager, says, “Understanding and predicting subsurface conditions is key to project success in a case like the Fukang Pumped Storage Power Station project. Until now the industry has had to rely on manual and adhoc solutions borrowed from other workflows. Leapfrog Works is a dedicated solution addressing these workflow challenges. It’s great to see how GEODATA harnessed the power of Leapfrog by building a 3D model from a range of disparate data sources, combined with engineering designs – enabling better insight and decisions to be made.”

Assessing The Support Structures’ Section

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