In Sweden, the Forsmark site, a sparsely fractured crystalline host rock, is selected to be the future location for building a deeply sited nuclear waste disposal. The use of highly detailed DFN (Discrete Fracture Network) based site models is required for both post-closure safety assessment and construction purposes. DFN-based models are considered the most accurate representation of the fractured system and of the geological context.
The Swedish Nuclear Fuel and Waste Management Company (SKB) is planning to extend the short-lived radioactive waste repository with five 275 meters long and one 240 meter long vault. Since the extension could lead to damage on the existing facility, Itasca designed a temporary support system to prevent loose rock.
In general, analysis performed on wind turbine foundations focus on the effects of the foundation’s rotational stiffness and deformation for a range of overturning moments. This project stage focused on the performance of the foundation and, given the local soil condition, its bearing capacity. To evaluate the behavior of the soil-structure interaction, a detailed numerical model of the concrete foundation and its steel reinforcement (i.e., rebar) was built and analyzed in FLAC3D.
In this project, the effects of deformation and rotation with regards to the pile length were observed. Specifically, four piles of a pile bridge were driven through an intermediate sandy layer and may have encountered a local anomaly (Figure 1). A safe assumption was to consider the anomaly to be clay. Additionally, the benefit of any additional helping elements to balance the stiffness distribution of the pile under the pile cap was evaluated.
The objective of the project is to predict the scaling evolution of rock mass effective elastic properties for conditions relevant to the POSE (Posiva’s Olkiluoto Spalling Experiment) niche surroundings at ONKALO, the Finnish site for underground storage of nuclear waste.
Wind farm construction requires large cranes to lift massive wind turbine structures over 300 feet tall and exceeding 160 tons. Installing these structures requires many crane “walks”, moving the heavy cranes around 50 miles along soil surfaces of varying strengths. Moving the cranes quickly is critical to installation economics, but this must be done safely by ensuring soil strength stability to avoid sinking or toppling the crane. Conventional best practices require cone penetrometer tests (CPTs) and performing numerical modeling to establish a safe path for moving the cranes requires on the order of four to six weeks. Itasca developed a rapid bearing capacity prediction tool using Python scripts, FLAC3D, and machine learning to provide near real-time feedback on the soil bearing capacity at a location, allowing enhanced crane walk planning.
Research, Numerical Investigations and Development of a Methodology for Longwall Mining at a Potash Deposit (2021)
Aim of this R&D project is the development of guidelines for the estimation of the water-conducting crack propagation above mined-out spaces above a potash deposit, using research and numerical modelling methods.
Exploration between the two closed mines Rävlidmyran and Rävliden has
successfully led to more mineralizations being discovered. Itasca has analyzed possible mining methods, mining sequences, design parameters, location of infrastructure, reinforcement, and backfilling requirements. A
Site modeling using DFN.lab (2021)
In Sweden, the Forsmark site, a sparsely fractured crystalline host rock, is selected to be the future location for building a deeply sitted nuclear waste disposal. The implementation of highly detailed, and DFN (Discrete Fracture Network) based, site models is required for both post-closure safety assessment and construction purposes. DFN-based models are considered as the most accurate representation of the fractured system and of the geological context.
Located in Catamarca Argentina, the Bajo de La Alumbrera open pit mine experienced a large-scale instability along its southwestern wall on May 31, 2017. Itasca performed additional numerical modelling analyses to back-analyze the 2017 instability to predict Factor of Safety (FS) contours and consider options to mine the remaining ore at the bottom of the pit.
The road construction department of district Steinfurt, a district in the north of the coal mining area in the Ruhr region, is planning the construction of the new road K 24n. The road axis runs through an area partly affected by old mining operations. These mining operations took place between 1880 and 1921.
As part of the EU Horizon 2020 ENIGMA ITN project, ICSAS, the CNRS, and SKB proposed a PhD project entitled “Flow and transport in fracture networks: reducing uncertainty of DFN models by conditioning to geology and geophysical data”, to develop and test a methodology for rock characterization that would help in the decision-making process for an adequate location of the nuclear waste canister burying.
Long-term storage of spent fuel is critical to the nuclear energy industry. The Swedish Nuclear Fuel and Waste Management Company (SKB) is developing an approach for the storage of spent nuclear fuel in an underground repository in competent crystalline rock. In order to better understand the spalling damage process, an in-situ test involving the drilling of two boreholes was performed in Äspö diorite at SKB’s underground hard rock laboratory in Äspö. Tests and monitoring were performed on the pillar that separated the boreholes. In order to further investigate the damage process, Itasca performed numerical modeling using PFC3D and FLAC3D.
SKB is interested in developing a 3D discrete model to predict spalling on the excavation boundaries of underground repositories for the long-term storage of spent nuclear fuel. This project provided a quantitative assessment of modeling spalling using PFC3D to study both lab- and tunnel-scale behavior.
The open pit mine is part of a Greenfield exploration project. Itasca Consultants GmbH in corporation with Itasca Chile were contracted to develop a stability design of the pit. The analysis has been performed using Itasca’s three-dimensional distinct element code, 3DEC (Itasca, 2016).