Browsing by Author "Rinne, Mikael"
Now showing 1 - 20 of 230
- Results Per Page
- Sort Options
- 3D stress state change monitoring using displacement measurements
Insinööritieteiden korkeakoulu | Master's thesis(2015-08-24) Ritala, FransThe purpose of this Master’s thesis is to test stress estimation algorithm created in Tekes Green Mining Programs Dynamine project. The test were conducted in Bo-liden Kylylahti mine and included two different test sites. The test sites were first modelled using Rocscience Examine2D and Examine3D to enable comprehensive positioning of used instruments. In total 14 extensometers were installed to the mine. Prior to real data analysis the algorithm was tested using synthetic data created with Examine 2D program. This was done to ensure that the modelling selections done for this study were adequate for the algorithm to be used. The testing with synthetic data was divided into three separate parts: analysis with far field modelling, near field modelling and with shear stress. The data received from the measurements was first converted from displacements to strains. After this the rock mass response of each of the test sites were examined. Based on these examinations the amount of data was narrowed down. The actual analysis were only conducted to the 2D test site. As with synthetic data analysis, the analysis were done for both near and far field. The results from the analysis were not in realistic magnitude. For some measurements good fits were found between measured and estimated strains. To eliminate possible measurements errors also data received from Posiva’s ONKALO test was analyzed but the results were similar to results gained from Kylylahti mine. In the last part of the study reasons affecting to the results were covered. The main reasons were joints passing thru extensometers, rock mass modulus and disturbed rock mass, measurement inaccuracies caused by the used measurement equipment and inaccuracies caused by the used modelling software. Also improvements for further research were stated. - 3D-laserkeilaus ja sen hyödyntäminen kalliorakentamisessa
Insinööritieteiden ja arkkitehtuurin tiedekunta | Bachelor's thesis(2009) Malmberg, Markus - Air deck -menetelmän soveltaminen kiviaineslouhinnassa
Insinööritieteiden korkeakoulu | Master's thesis(2019-06-17) Könönen, TeroKalliolouheesta jalostettujen kiviainesten kysyntä Suomessa on lisääntynyt ja niiden ennustetaan lisääntyvän vastaisuudessakin. Lisäksi kaikkein laadukkaimpien kiviainesten tuotantoalueiden määrä on hyvin rajallinen, joten kiviainestuotannossa lopputuotteen laatu tulee maksimoida ja hukka minimoida. Louhinta on tuotantoprosessissa olennainen osa, jota tulee kehittää tulevaisuuden tarpeiden täyttämiseksi. Tavallisesti kiviaineslouhinta toteutetaan avolouhintana, täyteen panostetuilla rei’illä. Tietyissä tapauksissa kyseinen menetelmä kuitenkin rikkoo kalliota tavoiteltua enemmän, jolloin lopputuotteen laatu heikkenee ja haitallinen, joissakin tapauksissa hukaksi luokiteltu hienoainesmäärä kasvaa. Aiempi tutkimus on osoittanut, että korvaamalla osa panostilan räjähdysaineesta ilmalla, voidaan kallion ylimääräistä rikkoutumista vähentää. Tätä kutsutaan air deck -menetelmäksi. Menetelmällä porareikäpaine pienenee ja kallioon välittyy useampi kuin yksi jännitysimpulssi. Tässä tutkimuksessa toteutettiin kaksi räjäytystä panostilan keskelle sijoitetulla air deckilla, eli väli-air deckilla, täyden mittakaavan tuotanto-olosuhteissa, lujissa kivilajeissa. Tavoitteena oli selvittää, voidaanko air deck -menetelmää soveltamalla vähentää lopputuotteen hienoainesmäärää, parantaa lopputuotteen kulutus- ja iskun-kestävyyttä, kasvattaa korkealaatuisen lopputuotteen saantia ja edistää kallion lohkaroitumista. Näytteitä kerättiin sekä air deck -räjäytyksistä että vastaavasta kalliogeologiasta, air deck -räjäytyksen vierestä suoritetuista vertailuräjäytyksistä. Vertailuräjäytykset suoritettiin perinteisellä menetelmällä eli etutäytteeseen asti täyteen panostamalla. Molemmissa kohteissa hienoainesmäärä joko louheessa tai lopputuotteessa pieneni air deck -menetelmää käytettäessä. Kulutus- tai iskukestävyyteen menetelmän vaihdolla ei ollut vaikutusta. Saannit paranivat molemmissa kohteissa siirryttäessä air deck -menetelmään. Lohkaroituminen ensimmäisessä kohteessa oli lähes vastaavaa ja toisessa heikompaa kuin perinteisellä menetelmällä. Air deck -menetelmää ei suositella otettavaksi käyttöön ilman kohdekohtaisia tutkimusräjäytyksiä. Menetelmällä on potentiaalia toimia lujissa kivilajeissa, jos kallio on tiheärakoista. Harvarakoiseen, lujaan kallioon menetelmää ei suositella sovellettavaksi. - Analysis of alternatives for primary crushing and conveying at the Siilinjärvi open pit mine
Insinööritieteiden korkeakoulu | Master's thesis(2014-08-25) Camargo Nino, Fredy - Analysis of new tools for equipment scheduling in underground mining and ore safety stock management
Insinööritieteiden korkeakoulu | Master's thesis(2015-11-23) Karstila, JuhaThis Master’s thesis was carried out to test the efficiency of an equipment scheduling optimization software, developed by Song et al., in 2014 for underground mining. Another focus of this thesis is in mine inventory management. More specifically in the optimization of safety stock levels of ore supply, using a real options model, developed by Song in 2015. Both the equipment scheduling software and the safety stock optimization model were tested at Agnico Eagle Kittilä mine with real mine parameters. A literature study for both topics was conducted. The study on equipment scheduling optimization software presents the background of the software and the used algorithms. The study on safety stock optimization presents the new real options model as well as the conventional model. Other focuses of the study include the possible blending strategies used in stockpiling and inventory systems that model safety stock in other industries. The equipment scheduling optimization software was tested at Kittilä mine and the discrepancies between actual and planned (software) operations were evaluated. This thesis presents the two most significant scenarios generated by the equipment scheduling optimization software. The results obtained from the tests suggest that the equipment scheduling software can decrease the travel distance and travel time of mining machines by as much as 21% on a daily basis. Additionally the results suggest that the operating efficiency at workfaces can be increased by 5% on a daily basis. A new method was created to optimize safety stock. This method focuses on the discrepancies in ore supply and mill demand. The new method was analyzed and integrated with the real options model to optimize safety stock levels. This method was tested with parameters consistent to the parameters of Kittilä mine. The result of the test provides a foundation for the needed safety stock levels on a yearly basis. Additionally, a decision model for mine inventory management in practice has been created and is presented in the results. The methods and models presented in this thesis represent solutions towards more optimized operations. However, these methods and models have been only tested for specific circumstances and therefore should not be generalized. - Analysis of the economic and technical feasibility of crown pillar extraction at the Björkdal gold mine by comparison of underground and open pit mining
Insinööritieteiden korkeakoulu | Master's thesis(2016-12-12) Vendla, Silja - Application of critical controls for fatality prevention in mining operations
Insinööritieteiden korkeakoulu | Master's thesis(2018-04-16) Franzen, SjoerdIn this study, a new risk management approach was applied to mitigate fatal incidents through the utilization of critical controls. The aim of this study was to create a scalable, minimally invasive proof-of-concept for AngloGold Ashanti that can successfully be implemented at any of the company’s mining operations. The system was designed by adhering to organizational requirements, and ensuring that it is suitable to any mining environment. The designed Critical Control Management System was subsequently implemented at Sunrise Dam, one of AngloGold Ashanti’s Australian mining operations. To ensure that critical controls were also assessed at the operational level, a workplace inspection process was modified to generate control data. All sources of data subsequently were fed into a Business Intelligence environment enabling insight into critical control performance to all company stakeholders. Doing so informs decision-making on safety priorities company-wide, based on real-time data generated on the operational level. Two case studies were performed to assess two of the most significant hazards at Sunrise Dam. The studies showed that the effectiveness of reactive controls changes irrespective of their compliance and performance. Furthermore, the influence of human factors within risk management remains difficult to quantify. Finally, it demonstrates the potential for integration of incident data into the Critical Control Management System, thus creating both leading and lagging indicators for safety performance. The conclusion of this study is that an effective and scalable Critical Control Management System can be successfully implemented in a mining operation if the right conditions are generated. The approach of integration in existing processes demonstrates that companies can achieve greater control over fatality prevention without the need for an additional safety management system. On this basis, it is recommended that other operations are supported in creating an environment suitable for adaptation before Critical Control Management is implemented. - An Approach to Realizing Process Control for Underground Mining Operations of Mobile Machines
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2015) Song, Zhen; Schunnesson, Håkan; Rinne, Mikael; Sturgul, JohnThe excavation and production in underground mines are complicated processes which consist of many different operations. The process of underground mining is considerably constrained by the geometry and geology of the mine. The various mining operations are normally performed in series at each working face. The delay of a single operation will lead to a domino effect, thus delay the starting time for the next process and the completion time of the entire process. This paper presents a new approach to the process control for underground mining operations, e.g. drilling, bolting, mucking. This approach can estimate the working time and its probability for each operation more efficiently and objectively by improving the existing PERT (Program Evaluation and Review Technique) and CPM (Critical Path Method). If the delay of the critical operation (which is on a critical path) inevitably affects the productivity of mined ore, the approach can rapidly assign mucking machines new jobs to increase this amount at a maximum level by using a new mucking algorithm under external constraints. - Arbetssäkerhet i sprängnings- och schaktningsarbeten i Finland och Sverige 2008-2018
Insinööritieteiden korkeakoulu | Bachelor's thesis(2018-12-11) Strandström, Fanny - Assessing dependability in construction tunnelling
School of Chemical Engineering | Master's thesis(2010) Verho, Tommi - An assessment of the underlying causes for the difference between theoretical and real-world production rates of mining shovels
Insinööritieteiden korkeakoulu | Master's thesis(2022-12-12) Meijer, TimThe goal of a mining operation is to extract the maximum value from exploiting the orebody. The equipment used by these mining operations has a nominally rated performance to achieve needed annual production. However, this nominally rated performance is not achieved during operations. This study assesses the underlying causes of reduced shovel production in a mining operation. The following research questions will be answered in this study: What factors contribute to deviations from the predicted performance? What factors are the most significant? What is the effect of automated trucks on shovel productivity? Can a data-driven model be developed to predict the actual productivity of the shovel in the real world? The underlying causes of reduced shovel production are assessed through a literature review and five case studies. The case studies consisted of three data analytical desk studies, interviews with industry professionals, and a mine visit to north Africa. The literature review shows that the mining industry uses formulas to determine the theoretical production rates. The factors in the shovel production formula should be predicted with frequency distributions. Also, truck automation will increase trucking hours, impacting shovel productivity through truck exchange time. The first case study shows a sensitivity analysis of the shovel formula. This sensitivity analysis shows that the swell factor, density, bucket fill, efficiency, and cycle time have a more significant impact than truck exchange time, dumping of the first bucket, and the number of cycles. The second case study shows the underperformance of different electric rope shovel models in different mining operations. The third case study compares the theoretical shovel capacity with the total material moved for 16 years. This shovel capacity and total material ratio should be between 1-2.5 for a mining operation to be classified as above-average-in-class. The fourth case study shows the different factors influencing shovel productivity based on the interviewees’ responses. The last case study shows the effects of operational decisions on a mining operation. The literature review and case studies are used to develop a flowchart regarding the factors influencing shovel productivity. This flowchart was used to synthesise the results. The difference between theoretical and real-world production rates can be decreased when the frequency distributions are known for all the shovel production formula factors. This shovel production formula for annual production rate can be divided into three main pillars. These three pillars are the hourly production rate, use of availability, and mechanical availability. The pillars allow OEMs or mining companies to implement the correct improvement measures to improve shovel productivity. However, one solution for every mining operation will be impossible due to the uncertainty in the data and variability of each mining operation. To conclude, the factors that contribute to deviations from the predicted performance are categorised as uncontrollable (weather and geographical location), direct (density and cycle time), and indirect (fragmentation and face dimensions), which all impact shovel productivity. The most significant factors are not found during the study, but solving underperformance in the direct factors will solve most of the problems. The effect of automated trucks on shovel productivity will result in additional trucking capacity, which will need to be absorbed by the shovel. Lastly, a data-driven model can be developed with access to all the data from a mining operation. However, this data is often not available to an OEM. Therefore, it is not advisable to develop such a model. - Benchmarking of a battery loader and its impact on the Garpenberg mine
Insinööritieteiden korkeakoulu | Master's thesis(2023-12-11) Kavermann, Nils LukasThe mining sector has evolved through various industrial revolutions, each marked by technological breakthroughs that enhanced productivity. However, the contemporary mining landscape confronts pressing challenges, including declining deposit grades, rising waste volumes, and the imperative to reduce carbon emissions. These challenges have spurred the fourth industrial revolution in mining, characterized by automation, artificial intelligence, and eco-friendly approaches such as battery technology. To address these challenges, this thesis investigates battery performance, productivity, energy efficiency, and swapping procedures of battery loaders in the context of the Garpenberg underground mine in Sweden. It involves collecting machine data, analyzing various driving patterns, and simulating the maximum distances between charging points and mining faces. The study also explores different settings in simulations, estimates investment costs, and evaluates the potential impact of transitioning the entire LHD fleet to battery-powered equipment on production and the power grid. While this research presents valuable insights into the adoption of battery-electric equipment in mining, it acknowledges certain limitations due to confidentiality requirements and focuses on averaged values. The study does not delve into the impact of battery loaders on the ventilation system, operator performance, or provide a detailed cost analysis for all involved parties. Nevertheless, the findings offer guidance to mining companies considering battery-electric solutions and contribute to the design of charging infrastructure in underground mines. - Mallipohjaisen louhintaprosessin hyödyntäminen tiehankkeessa
School of Engineering | Master's thesis(2013) Vaaramaa, OlliDestia Oy has been developing a model-based rock excavation process since 2008. By development work, the company is seeking, for example, better financial profits and better methods of making quality assurance reports. The purpose of this thesis is to find out what benefits have been achieved and what can be achieved. 3D-Machine control system, which is integrated to the drilling rig, is a multidisciplinary entity. The current system in use is exploiting GNSS-positioning with a variety of methods to delineate it for the positioning of the machine. It also uses a variety of sensors for exact positioning of the tool. The user interface of the system is located in the cabin. From there you can handle drill plans and surface models. Usually drill plans are created beforehand at the office but in some cases they can be created with the 3D-system in the cabin. Examination of achieved benefits happened at Tikkurilantie's rock excavation project. Research on site was performed in order to clarify the benefits of the system in various fields of the project. In this thesis the system's influence on effectiveness of drilling, the usage of the system's output data for rock mass calculations, the possibilities of optimizing blasting fields, the reliability of data acquisition system and the system's financial impact on the project are examined. During the research, it was noticed that drilling was far more efficient than it was calculated. The system's output data in rock mass calculations were examined by comparing various rock surface models constructed by different methods. Results point out that output data are not suitable for rock mass calculations in their own right, but are an excellent tool for checking and completing mappings. The system which collects and stores performance times and quantities turned out to be unreliable. It was also found out that in model-based rock excavation methods; there is an opportunity to lower the project's costs by optimizing blasting fields. The influence on the project's finance was also examined. Research points out that about 10 % of the realized contract value was actualized due the model-based rock excavation system. - Bottleneck identification and analysis for an underground blast cycle operation
Insinööritieteiden korkeakoulu | Master's thesis(2017-10-30) Grynienko, MichalIncreasing demand for raw materials and base metals together with severe environmental regulations influence mining operations to be more economic, competitive, and sustainable. Since mining involve numerous operations which difficulty ranges from simple to very complex, each of them need proper design, performance and optimization. Mining operations including activities within blasting cycle affects productivity the most, and thereby their planning and performance is the most important from production point of view. Since blasting cycle operations include many complex activities where many inner and outer factors have an influence on operating efficiency, it is crucial to thoroughly investigate the system every time new problems arise or when looking for improvements. According to Theory of Constraints every production system has at least one bottleneck. Blast cycle operations may be treated as a system regarding production. Therefore, there is/are constraint(s) which should be solved and bottleneck(s) should be debottlenecked. It is in demand to properly identify constraints within the blasting cycle operations and subsequently take measures to improve them for enhanced production results. Due to system complexity and presence of many factors and variables it is efficient to use some techniques that will facilitate analysis. Discrete event simulation approach makes it possible to analyze underground mining operations and identify critical points where improvements could be made. In these thesis computer simulation approach, together with concepts derived from theory of constraints were used to identify bottleneck and perform its analysis. Many simulations were conducted to search for improvements and indicate those with the highest potential for development and increase of production. - Building information modelling of rock reinforcement
Insinööritieteiden korkeakoulu | Master's thesis(2018-12-10) Pihlström, MaxBuilding information modelling has been effectively around for a few years now in the field of rock engineering but the topic of creating rock reinforcement structures (rockbolts and sprayed concrete) has not been studied in this extent before. This thesis studies the process of creating rock reinforcement structures with Autodesk’s AutoCAD Civil 3D software to achieve compatible rock reinforcement structures with the present buildingSMART’s common InfraBIM YIV2015 requirements. In addition, the goal is to achieve an editable rock reinforcement structure. A further goal is to study supporting features for rock reinforcement information building models. During the making of the thesis, two real case projects are modelled and they are used to examine the set goals. Modelling of excavation surfaces is a prerequisite to enable the design and modelling of rock reinforcement structures, which is achieved. As an outcome of this thesis, the rock reinforcement structures are modelled successfully and requirements presented in the YIV2015 for rockbolts and sprayed concrete are successfully fulfilled. Modelling of rock reinforcement structures proves to be a straightforward process when working with simple excavation geometries but more challenging and laborious when applied to more demanding excavation geometries. An editable rock reinforcement structure is important to enable adaptation to the site’s changing conditions which is achieved during the making of this thesis. However, this does not quite match the author’s vision of efficiently editable rock reinforcement structure. The subjects of parametric and dynamic modelling along with supplementary add-ons and other design platforms are important, as they are the key for achieving such a structure. Supportive features are studied to offer more tools for rock engineers. The results presented in this thesis enable rock engineers to add their designs to combination models along with other design fields. It is important to maintain and develop instructions and requirements, like YIV2015. The instructions and requirements guide designers to create uniform models despite the used modelling software to enable a good method of construction in the future. - Maankäytön haasteita Päijänne-tunnelin vaikutusalueella Vantaalla
School of Engineering | Master's thesis(2012) Vahtera, EevaThe Päijänne Water Tunnel, which passes through the city of Vantaa, is a raw water tunnel providing fresh drinking water to the residents in the Greater Helsinki area and its industries. Construction in these areas is increasing rapidly. Consequently risks exist for both the builders who work in the Päijänne water tunnel's geographic region as well as in the tunnel itself. In Vantaa there are already various potential contamination sources such as the Helsinki-Vantaa Airport. Substantial documentation on the Päijänne water tunnel exists; however, these are not comprehensively collected and analysed. Pääkaupunkiseudun Vesi Oy, the administrator of the water tunnel, considers it important for the builders to have adequate information about the tunnel in all its construction and planning stages. The tunnel and its protection should be closely monitored when planning land use thus improving risk management in construction. For this study information was collected and three different cases were examined. The cases exposed some challenges in the near future regarding land use planning in the area. Some of these challenges are the traffic tunnel planning in Hakakorpi, the development of the Lavanko area and geothermal heating in the Päijänne water tunnel's target area. The analysis focused on the preliminary geological research on the water tunnel, the documentation on its construction, and the reports made from the general overhaul of the tunnel and the environmental audits. According to the research, cost of building traffic tunnel similar to Hakakorpi's increase ca. 3% due to proximity of the Päijänne Water Tunnel. While planning Vantaa Speed Center in Lavanko, environmental impact assessment would yield valuable data about projects impact on environment and also about Päijänne Water Tunnels effect on the project. Environmental effects of geothermal heating wells in groundwater catchment areas and in the Päijänne Water Tunnel target area require further study. Possibility of prohibiting deep boreholes in the bedrock within 50 meters of the Päijänne Water Tunnel should be looked into in accordance with Pääkaupunkiseudun Vesi Oy's guidelines. It is important to raise this issue about land use affected by the Päijänne water tunnel among specialists from several branches of science. Through cooperation the best compromise between land use and protection of the Päijänne water tunnel can be reached. - Characterization of hydro-mechanical properties of rock fractures using steady state flow tests
A4 Artikkeli konferenssijulkaisussa(2020-11-13) Uotinen, Lauri; Torkan, Masoud; Janiszewski, Mateusz; Baghbanan, Alireza; Nieminen, Ville; Rinne, MikaelCharacterization of Hydro-Mechanical (H-M) properties of rock fractures is the initial and important step in modeling of fully H-M coupled processes in fractured rock masses. Fluid flow in the fractured rock mass is an important aspect when evaluating the safety of geological disposal of high-level nuclear waste. Many attempts have been taken to measure and model fluid flow in rock fractures in different stress field conditions. However, still study about the scale effect of fracture properties and confinement stress on the conductivity of rough rock fractures remains a challenging topic of research. As a part of an ongoing research project about fluid flow modeling in fractured rock mass (RAKKA), and as an initial step one rock slab pair with sizes of 250 mm x 250 mm of Kuru grey granite halves was prepared. It has a horizontal mechanically induced tensile fracture. The surface roughness of the fracture was mapped using a conventional profilometer and structure-from-motion photogrammetry before each fluid flow test. The fractures were subjected to different normal stress and then fluid flow within the fractures was conducted linearly from edge to opposite edge with perpendicular edges sealed, and conductivity of the fractures under steady-state condition was measured. Then the test is repeated with all three sides open. The results show anisotropic behaviour in permeability. The diagonal components of the permeability matrix are significantly stress-dependent. Together the new fracture digitization method and the new three-way fluid flow test allow the contactless characterization of hydro-mechanical properties of rock fractures and the validation of the results. - Characterization of hydromechanical properties of a rock fracture using numerical modelling
Insinööritieteiden korkeakoulu | Master's thesis(2022-06-13) Nieminen, VilleThe hydromechanical processes of a single rock fracture are dependent on the properties of that single rock fracture as well as the properties of the rock fractures that are connected to it, and their geometry, orientation and the effective stress of the fracture walls. Hydromechanical properties of a single rock fracture are governed by several parameters such as contact area, roughness, tortuosity, aperture, channeling, matedness, sample sizes, normal stress, flow regime, and flow boundary conditions. Numerical modelling was used to compare the influences of roughness, aperture, water pressure, and different flow boundary conditions on fluid flow in an artificial granite fracture. Comprehensive fluid flow analyses were made to better understand the flow behaviour, including the streamlines, flow velocities and inner water pressure distributions. A simulation model for fluid flow in a single rough fracture was developed with the COMSOL Multiphysics finite element method software. The resulting model was numerically simulated with COMSOL using the Navier-Stokes equations. In this thesis, 20 fluid flow simulations were performed on fracture model created from photogrammetry of rock block with the size of 250 mm × 250 × 110 mm containing artificial tensile fracture. Laminar fluid flow inside the fracture was simulated with fluid flow through x- and y-axis at increasing water pressure level at normal stress conditions of 0 MPa. Simulated water pressures were from 5 kPa to 50 kPa with 5 kPa interval. The numerical model was successfully verified against experimental laboratory work. The numerical simulation results show that the relationship between water pressure gradient and the flow rate is nonlinear indicating turbulent flow behaviour. The channelling effect of the fluid flow as well as the pressure distribution along the fracture increase with the increase of water pressure. The growth of fluid flow velocity inside the fracture with the increase of water pressure is nonlinear and the growth rate of the fluid flow velocity decreases as the inlet water pressure increases. Comparison between the numerical modelling results and the experimental solution confirms that the 3D roughness geometry has a crucial role in defining the transmissivity, especially for nonlinear flow. The presented method can be used to characterize to flow properties of fractured rock and in evaluating different methods and implementation of underground rock engineering applications. - Comparison of Barton-Bandis and Mohr-Coulomb models for use in discontinuity shear stability analysis
Insinööritieteiden korkeakoulu | Master's thesis(2015-10-19) Iakovlev, DaniilFor mining and civil engineering projects rock slope stability is an essential part of safety and financial considerations. While large-scale stability can be simulated using rock mass properties, at smaller scale local variations in rock properties become significant and failure purely along discontinuities is possible. Wedging and rockfall are common occurrences at this scale. These are often prevented by bolting or shotcrete support. For temporary slopes such support measures can be costly, and an ability to simulate possible failures along discontinuity planes becomes useful for evaluation of support necessity. Traditionally the Mohr-Coulomb failure model has been used. However, a model has been developed specifically for discontinuity shear strength analysis. This Barton-Bandis model is based on basic friction of rock and joint roughness. This study aims to compare the two models in practice both for accuracy and resources required. This is accomplished by carrying out a case study on the Siilinjärvi mine site rocks. Parameters for both models were collected with laboratory and in-situ tests. These included shear box, Schmidt hammer and tilt table tests as well as joint roughness profiling. The variability of these parameters was analysed and certain parameters were selected as the most appropriate for simulation. Several failure and non-failure cases were then simulated using these parameters to check their validity. Parameters were easier to obtain for the Barton-Bandis model. Additionally, the variation in Barton-Bandis predictions for each sample was considerably smaller than the variation for Mohr-Coulomb predictions, and using the average of Mohr-Coulomb parameters would create a dangerously overconfident estimation of strength. Barton-Bandis results were easier to interpret. Parameters selected for simulation were preliminarily shown to be valid. It was found that joint continuity is a decisive factor for simulation even at small scale, and that assuming continuous joints can create disproportionately conservative strength estimates. - Comparison of constructing of an underground and open-pit parking facility within hard rock in an urban area
Insinööritieteiden korkeakoulu | Master's thesis(2024-08-19) Rathnayaka Mudiyanselage, AchinthaCities are proliferating, attracting more people, where the demand for adequate parking spaces continues to rise while diminishing the free buildable space. Underground parking facilities offer a way around this problem. Building underground can be done in two major ways, either as a parking facility in a tunnel or as an open pit version. In countries where the bedrock is at a shallow depth, even open pit excavations would include hard rock excavations. Given the impact a large excavation would have on nearby existing structures, especially considering the highly disruptive nature of rock excavation techniques, it is important to assess the rock mechanical feasibility of the two options when selecting the appropriate method. Further, it is also vital to determine the environmental impact and overall cost to identify the most favorable approach. This thesis explored a case study of a rock mechanical analysis from the Meilahti hospital area where an open-pit parking facility was proposed. A hypothetical underground tunnel version of the parking facility was developed to assess its rock mechanical viability using 3DEC numerical modeling software and compared the results with the open-pit version. Further, total CO2 emissions related to rock construction works were computed using One click LCA software, and the expected theoretical rock construction-related cost of both options were calculated and compared. Simulated displacements are compared where in the tunnel version the displacements at surrounding structures were ranging from 2…3 mm. In comparison, in the open pit version, the simulated displacements are rather high, even more than 10 mm at some locations. Higher displacements could result in severe fractures in the existing tunnel's shotcrete layer, as well as foundation settlement in surrounding structures, causing shear cracks in the walls. In terms of CO2 output, both variants emit a closer level of CO2 with a slightly low percentage difference in the tunnel version. Further, there was a considerable difference in the total rock construction-related cost where the open pit version would cost nearly 1.5 times as much as the tunnel version. These results can be used as a base guideline to determine the best alternative in densely populated urban regions for any planned underground structure