GeoCorner

Piling operations are typically carried out in weak ground conditions, which means that a working platform must be designed and constructed so that safe and efficient operation of piling equipment is enabled. A working platform is typically a ground-supported structure composed of compacted crushed aggregate. Currently, there is no standard either in Finland or internationally for designing working platforms and no consensus has been reached on how it should be carried out.

The objective of this master’s thesis was to examine existing design methods for working platforms and explore practices to ensure their quality. In addition to literature review, the study included computational analyses of platform design for various types of piling rigs under differing ground conditions. The design methods investigated were BR 470, TWf 2019, T-value and the bearing capacity formula B.6 presented in the second-generation Eurocode SFS-EN 1997-3:2025. Also, comparative stability calculations were performed.

In the calculations, the loads induced by the piling rigs were determined according to standard SFS-EN 16228-1, which must be used for Eurocode-based design. All the design methods are primarily based on relatively simple analytical expressions whereas piling work itself represents a rather complex loading situation.  Consequently, the methods involve numerous limitations, and the resulting platform designs obtained were generally quite conservative. The stability analyses produced platform designs that most closely reflected current practical approaches.

The purpose of in-situ testing of a working platform is to ensure that the platform has been constructed according to the design and is suitable for the intended piling work. The key aspects of quality control are verifying sufficient bearing capacity and compaction, which can be assessed using plate load tests or measurements with a falling weight deflectometer. Because of the limited depth of influence of these tests, it is recommended to verify, for example through trial pits, that the actual thickness of the platform corresponds to the design.

Virtual Reality (VR) and Augmented Reality (AR) tools are rapidly gaining a place in the mining industry, from safety training and equipment simulations to mine designing and planning. Therefore, more companies are financing R&D projects to explore innovations such as VR and AR. The surging use of VR in the mining industry inspired this thesis project, with the aim of expanding its application to core logging. The objective was to make data available for geologists to visualize, interpret, and analyze remotely. 

This thesis describes, in detail, the complete workflow to build a virtual core tray that integrates analytical and visual data. Each core was modeled using two datasets: LIBS (Laser Induced Breakdown Spectroscopy) and RGB photogrammetry-based mesh. The study focuses on the Terrafame deposit’s archive drill core box to create a bridge between conventional core logging and VR. The workflow combines different tools and devices: LIBS data acquisition with Lumo Analytics LASOLIBS, data processing with Jupyter Lab, and mesh reconstruction in CloudCompare. The RGB models were acquired after high-resolution photogrammetry and model reconstruction using RealityScan. Both datasets, deriving from distinct sources and coordinate systems, were aligned, merged, and scaled with Blender to ensure spatial and visual accuracy. A total of 25 core models were combined in Unity to recreate the drill core box, forming the base of an interactive VR core logging scene designed for the Meta Quest 3 headset. Adapted C# scripts enable realistic interaction features such as rotating, scaling, zooming, and toggling between both meshes to visualize the mineral composition and study the surface texture. 

The results show that integrating different datasets, from different sources, within a VR environment requires a detailed structured workflow with precise settings and parameter control. Users’ feedback from live demonstrations showed that this vision has strong potential as an efficient tool for geological data visualization and education. While conventional core logging remains dominant, this work focuses on how immersive technologies can complement current methodologies in the future.

Abstract

This study evaluates the potential of 3D Gaussian Splatting (3DGS) as a novel 3D digitization method for rock mass characterization. The main focus was on the relative accuracy of 3DGS, its efficiency, and visualization capabilities compared to the traditional photogrammetric methods and manual field method. Gaussian Splatting generally enables the creation of real-time, photo-realistic 3D reconstructions through a point-based rendering technique that blends both geometry and texture data. This research investigated optimal data acquisition and processing workflows, the influence of device capabilities (mobile versus desktop), and the applicability of 3DGS under challenging underground conditions.

Using datasets obtained from the Underground Research Laboratory of Aalto University (URLA), models of 3D Gaussian splatting were made with Jawset Postshot software and geometrically compared to mesh-based photogrammetry and point cloud-based photogrammetry. Rock Quality Designation (RQD) measurements were extracted digitally with the three methods and compared with physical scanline measurements to assess geometric accuracy. Statistical analyses, including correlation coefficients and Root Mean Square Error (RMSE), were used to quantify accuracy among the different techniques.

Results indicate that 3D Gaussian Splatting achieved a higher correlation with the physical measurements compared to the mesh-based photogrammetric method, and a subsequent lower RMSE to the mesh-based photogrammetric methods using the point cloud-based photogrammetry as reference, this shows the superior geometric fidelity of 3DGS to the mesh-based photogrammetric methods. Visual quality assessment by human participants also showed that Gaussian Splatting produced sharper, more complete, and colour-accurate representations. Although specular reflections and low-light noise presented challenges, 3DGS still outperformed traditional mesh-based photogrammetry in measurement consistency. These findings highlight 3D Gaussian Splatting as a promising tool for rapid, accurate, and interactive rock mass documentation and analysis in underground engineering applications.

Abstract

Safe and sustainable closure of tailings storage facilities (TSFs) under extreme and variable climatic conditions demands surface covers that are both hydraulically resilient and locally adaptable. This study develops and evaluates a novel unsaturated multilayered cover system (MLCS) designed as an all-weather barrier capable of maintaining stability and hydraulic integrity under wet, dry, and extreme rainfall conditions. The cover was constructed mainly from locally available geomaterials including a 5% biochar–-tailing mixture (150 mm), gravel drainage layer (50 mm), 35% clay–-tailing mixture barrier (150 mm), integrating a thin hydrophobic tailing barrier layer (20 mm) to enhance infiltration resistance. Comprehensive laboratory column tests were conducted to determine the soil–-water retention curves (SWRCs), soil hydraulic conductivity functions (SHCFs), and infiltration responses of individual geomaterials and the temporal hydraulic response of the novel MLCS under 115 mm ponding condition corresponding to 500-year rainfall return period in Helsinki, Finland. The hydrophobic tailing layer maintained impermeable until its water entry head (WEH) of around 4.71 kPa, as measured in breakthrough head tests. Calibrated numerical models using SEEP/W successfully reproduced the transient evolution of suction, water content, and percolation. The proposed MLCS showed outstanding performance under extreme ponding. With the hydrophobic layer, no percolation occurred for 61 days, and the upper layers reached near-saturation while the underlying tailings remained unaffected. Numerical simulations further indicated that even with loss of hydrophobicity, percolation was delayed by about 4 days and subsequent rates remained low. The proposed MLCS thus represents a sustainable, cost-effective, and climate-resilient all-weather cover system, offering long-term protection and environmental safety for TSF closure applications in cold and humid mining regions.