Task 4.2 Geo-spatial attributes digital twins design and development

Partners involved

SUBTERRA has participated and lead T4.2 along with MARINI MARMITITANIA and LA PARRILLA, which have been involved as end users.

Objectives and outcomes

The main goal of Task 4.2 is to develop geotechnical digital twins in the end users locations. Task 4.3 will use the outcomes of this task, by using outputs of La Parrilla numerical model, to develop the ROMs for the digital twin.

What has been done in Task 4.2?

In this task, three digital twins have been developed: La Parrilla, Titania and Marini Marmi.

The calculation model of La Parrilla has been finalised, using the FLAC 3D software. For this model, the geometries obtained from the drone flights have been taken into account, as well as the data from the installed sensors described in the previous WP2.

In a first step, the actual 3D model of the tailings pond has been represented, using the photogrammetric restitution of the images obtained by the UAS technique. This first approximation serves to compare the geometries in the different flights performed, as well as to detect the appearance of cracks or other elements that could compromise the integrity of the structure.

The first step in the development of the numerical model is the elaboration of the geometry. The meshing of the elements is a complex process, but it requires maximum detail so that the subsequent calculations are not affected due to an incorrect selection of the elements that make up the tailings pond. In the elaboration of the geometry of the model, all the constructive elements present have been taken into account, as well as the materials used for the waterproofing of the ground to avoid the infiltration of percolating water into the subsoil by means of the application of a geomembrane.

The results shown in Figure 1 correspond to the current situation of the tailings pond, where a groundwater level is located below the dam, and a non-evolving pore pressure due to the cessation of activity at the La Parrilla mine.

Figure 1. Numerical model results for current scenario in La Parrilla Tailing Storage Facility

The numerical model for Titania follows a similar methodology to that presented for the La Parrilla model, although in this case the behaviour of a slope in the open pit is simulated. The photogrammetric restoration of the different flights has been carried out and the geometries have been compared. These data have been taken into account for the geometry. Figure 2 shows the geometry obtained in the most recent UAS flight (November 2022). Figure 6 shows the area to be calculated, where the greatest instabilities occur. The geometry that FLAC 3D will use for the calculations has been obtained.

Figure 2. 3D model generated using UAS images performed in the last visit to Titania.

The Marini Marmi model represents the update on the progress of the underground works. At Subterra, this progress is received periodically from Marini Marmi Team, and is represented in a 3D model created with Leapfrog. In this model, the progress of the underground galleries can be observed, as well as their crossing through complex zones such as faults, or low resistance materials such as clays. Figure 3 shows an image of the 3D model representing the excavated galleries. The sections that are not represented in 3D show the progress planned but not executed yet.

Figure 3. 3D model of Marini underground galleries excavated.