Geoengineering master's theses

Author: Hannu Saarentaus
Supervisor: professor Leena Korkiala-Tanttu
Advisors: Silke Savikurki and Tiina-Liisa Toivanen (Espoo)
Funding: Espoon kaupungin geotekniikkayksikkö

http://urn.fi/URN:NBN:fi:aalto-202105236860

Abstract:

The aim of this thesis is to examine undrained shear strength in fine grain soil between two different field vane testing equipment. The research is funded by city of Espoo and its geotechnical unit. Espoo has had Nilcon type mechanical field vane test device for a long time and the other device acquired in spring of 2020 is manufactured by Geomachine. It is partly automated, electrically working and its model name is GM4W. Working with the newer device has been found more time consuming. The aim of this study is to investigate how the results from different apparatus can be compared. In addition, working time with the newer device is studied and effects on measured shear strength is investigated whether the process is made faster. Field vane testings were performed in four different locations in Espoo between October and December of 2020. Testing sites were Finnoonpuro, Kalajärvi, Monikonaukea and Tapiola sports park. Factors affecting the choice of investigation areas were depth and extent of the clay layer and origin of the area.

From two to three investigation pairs were conducted in each area with both equipment. A total of 216 results for undrained shear strength were obtained from 21 different test holes. Previously gathered investigation data from city of Espoo’s database were used in two investigations. In addition to the field vane testing, undisturbed soil samples were also taken from the sites and total of 70 samples were investigated in laboratory. Soil type based on grain size distribution, water content, porosity, unit weight and humus content were determined. Fall cone tests to determinate shear strength were also performed to those samples which it was possible.

It was observed that the results with Nilcon device were higher in most cases compared to GM4W. The difference between undrained shear strengths were 0,1…23,9 kPa. Highest differences in shear strength might be explained by heterogeneous feature of soil, but some differences were also observed in performing the investigations. With Nilcon it is not possible to fully follow the instructions defined to execute field vane testing. One of the major factors is rotation rate of the vane. It is difficult to keep constant and it easily gets higher than instructed. Also, with existing Nilcon setup the use of protective casing around the rods to prevents friction from the soil is not possible.

As a testing equipment the GM4W was found more reliable because the measurements could be repeated more reliably and the guidelines for field vane testing could be followed. After initial settings the test results are already in electronic form at GM4W and easy to use. They don’t need interpretation after measurement like the results when using Nilcon.

Author: Jonas Heinzler
Supervisor: Prof. Mikael Rinne
Advisor: Dr. Martin Held and Evan Hagenlock (Austin Powders)

http://urn.fi/URN:NBN:fi:aalto-202105236859

Author: Heidi Kaukinen
Supervisor: Jussi Leveinen
Advisor: Ari Huomo
Funding:  Väylävirasto

http://urn.fi/URN:NBN:fi:aalto-202105236881

Abstact

Project part calculation is a calculation method which is used in the early phases of infrastructure projects. This calculation method tries to predict the cost estimates of infrastructure projects, while the raw data is insufficient and uncertain. Project part calculation can be described as a tool to set cost target and to manage the expenses. Project part calculation method models the costs according to extent, circumstances and target quality level of infrastructure projects.

This research answers which needs project part calculation meets, what raw data can be used in project part calculation and can infra modelling be used in project part calculation. This research approaches part calculation in transport infrastructure projects’ point of view, more accurately road and rail projects’ point of view. However, road projects’ point of view is highlighted more.

This research used interviews as the research method. Various skilled experts in the infrastructure field were interviewed. It is important to identity all the raw data nevertheless raw data is insufficient and uncertain. Dividing infrastructure projects into parts should be done systematically and according the standards. It is important to highlight solutions, which are the most lucrative in the end.

Author: Fanny Strandström
Supervisor: Mikael Rinne
Advisor: Miika Kalliokari
Collaborative partner: Kalliosuunnittelu Rockplan Oy ltd

http://urn.fi/URN:NBN:fi:aalto-202105236886

Abstract
Sealing the tunnels against water inflow is an important step in tunnel construction projects. Finland and Sweden have similar geologies, that is why it is interesting to observe that the grouting design approaches differ from each other significantly. This thesis is a comparative study where the differences in grouting design and execution of grouting in Finland and Sweden are mapped. A case study is also conducted in this thesis.  

In Finnish civil projects the grouting design is based on experiences and empirical knowledge, while in Sweden, a much more theoretical approach is applied when drafting the grouting design. The reasons behind these differences are discussed throughout the thesis. The view in Finland is that the geology is difficult to precisely predict as the rock’s properties measured in the pre-investigation phase are point specific. For this reason, a design that can be self-adjusting and adapted to the actual site conditions is important. This is obtained by  conducting measurements at probe-holes and grouting holes prior to the actual grouting activity and based on the results of the on-site measurements, the design parameters are updated and evaluated by the designer. In Sweden, the view is that the best grouting results are obtained by adapting analytical equations to the design. The expected apertures are calculated analytically based on the measured transmissivities and conductivities in the pre-investigation phase. Then, the penetration lengths and the necessary grouting times are calculated with the equations presented in chapter 3. The different design approaches lead to very different grouting parameters in regards of both pressure and pumped volumes.

In the case study the extensions of the capitol city subway lines in Finland and Sweden are compared and the grouting of the nuclear repositories’ test tunnels in ONKALO, Posiva and the TASS tunnel in Äspö are compared.  

The differences in the grouting design and execution of the grouting design in the West metro subway extension in Finland and Blue Line project in Sweden were significant. In the West metro project higher pressures were used and the maximum allowed grouting volumes were up to 26 times larger compared to the Blue line project. It was also interesting to see that more pre-investigations were done in the West metro project compared to the Blue line project, even though the Blue line project used the theoretical approach in the grouting design.  

The repositories differences in grouting design were minor. In Finland freshwater grouting is conducted prior to the actual grouting to clean the fractures while in Sweden, it is unknown if this additional step is being taken.

Keywords: Grouting, Länsimetro, West metro, Blue line, Repository, Posiva, SKB, Tunnelling, Hydrogeology  

Author: Mia Roslund
Supervisor: Mikael Rinne
Advisor: Jari Heikkilä

http://urn.fi/URN:NBN:fi:aalto-202105236913

Abstract

Underground wastewater treatment plants (WWTP) are becoming more popular especially in urban environments.  Going underground does not only resolve the need for space but also removes the harmful side-effects of them  for the neighbors by making them out of sight. In countries such as Finland where the bedrock level is high  building underground usually means they are excavated into rock. These have been built for several decades, but not widely studied.  The objective of this study was to make the future design easier, more efficient, and more  straightforward. This objective was achieved by finding which are the boundaries for the design and what are the  effects of these boundaries on the design process. This was done by literature research and case studies.

Based on the literature it was found that functional boundaries for design of an underground WWTP are water state and level in receiving water course, wastewater quality and quantity. The water state in receiving water  course together with the wastewater quality and quantity define the treatment goal. The geotechnical boundaries for a design found in literature are required rock pillar and roof thickness, predicted weakness zones, most critical plant geometries, geological surveys, laboratory results, and rock mechanical simulations. Boundaries not specified for either but having influences on both are influent and effluent tunnel alignments and above ground  circumstances.

The boundaries found in the literature were studied in two case studies, Blominmäki and Sulkavuori WWTP design projects in Finland. The studied cases confirmed that the listed functional and geotechnical boundaries applied in the design of these WWTPs. These boundaries for design were the ones that either gave out important information or once found were variables that are unable to be changed. In their own way each of these
boundaries gave the design a direction and helped to find what is inevitable and needs to find a solution for.

Keywords: Underground wastewater treatment plant, rock design, WWTP design, design boundaries

Author: Markus Prittinen
Supervisor: Jussi Leveinen
Advisor: Dr Mateusz Janiszewski
Funding: none

http://urn.fi/URN:NBN:fi:aalto-202105236935

Abstract

It is important to have good data for making safe tunnel designs. An understanding of the prevailing discontinuities is crucial to evaluate the quality of the rock mass and reinforcement needs. Photogrammetry using Structure-from-Motion is a 3D-scanning technique from which one can make 3D representations of real-life objects using 2D-photos. The 3D-models allows for more automated and faster discontinuities mapping than traditional compass methods. The research location is the Underground Research Laboratory of Aalto University (URLA), which is a tunnel complex located in underneath Otaniemi campus at Aalto University in Espoo Southern Finland.

The research questions are: What are the challenges in tunnel photogrammetry? What are the most efficient methods in capturing tunnel environments? Are 360- and action cameras a viable alternative to more traditional photogrammetry methods using DSLR cameras? Do the methods used produce 3D-models good enough for identifying rock futures and for doing measurements and discontinuity mapping?
In this thesis different cameras are compared for Structure-from-Motion photogrammetry, a DSLR camera, a 360-camera, and a GoPro rig that was developed during the research. The GoPro rig combines four GoPro action cameras using a plastic frame and 3D-printed parts and can be used both handheld and on a tripod. An experiment is done using constraints for how close to an unsupported walls work can be done, to simulate a tunnel under construction. The accuracy, speed and resolution of each method is measured. The geometric accuracy is compared with measurements from a laser measurement tool. Traditional compass measurements of discontinuity sets are compared with measurements from 3D-models gathered, including semi-automated measurements of discontinuities in Discontinuity Set Extractor. The results show that out of the methods compared the DSLR method is most accurate and the 360-camera least accurate, yet each method produces a point cloud accurate enough for automatic discontinuity set measurements. Out of the methods tested the GoPro rig was proven to be both the fastest and cheapest method in acquiring images for photogrammetry.

Author: Ying-Ching Lin
Supervisor:  Solowski Wojciech   
Advisors: Lauri Savolainen (Ramboll Finland Oy) and Taavi Dettenborn  (Ramboll Finland Oy)
Funding: Foundation for Aalto university science and technology

http://urn.fi/URN:NBN:fi:aalto-202106207504

Abstract: 

Railway embankment design plays an important role in ensuring comfort, safety and timely operation of railways, which are the three greatest concerns for railway passengers and operators. When adopting a material in railway embankments, which is Leca LWA in this thesis, it is necessary to evaluate it from geotechnical design perspectives.

To demonstrate the use of Leca LWA in railway structures, this thesis aimed to determine the suitable cover and the optimal location for Leca LWA in railway embankments, as well as to evaluate the effect of high cycle train loads on Leca LWA. These were done by analyzing three key aspects in railway geotechnical design including bearing capacity, embankment stability and the displacement induced by cyclic loading. Numerous combinations of different thicknesses of railway substructure layers with multiple subgrade options were adopted for these analyses to serve the purpose of determining the most advantageous depth and location for Leca LWA.

The bearing capacity was verified by using the Odemark method. The embankment stability of railway embankments was computed by using Plaxis. The displacement induced by cyclic loading was analyzed by using Plaxis SSC model, which accumulated the plastic strain over time. The analysis results were further used to validate the HCA model established by Wichtmann et al., (2005). This HCA model was used to replicate the result of cyclic compression tests on Leca LWA, which the plastic strain was accumulated due to high cycle loads. Consequently, this thesis achieved to estimate the magnitude of plastic displacements under high cycle train loads by correlating the time provided by Plaxis simulations and the number of cycles given by the HCA model.

This thesis could benefit the designers who are interested in using Leca LWA as a railway embankmentmaterial. Additionally, this thesis brought the opportunity of using the HCA model and Plaxis SSC model to simulate the accumulated plastic strain due to high cycle train loads. 

Author: Jyri Liukko
Supervisor: Mikael Rinne
Thesis advisor: Visa Myllymäki

http://urn.fi/URN:NBN:fi:aalto-202106207529

Abstract:

The aim of this master’s thesis was to define the carbon footprint of a rock construction
project, when traditional drill & blast -method is being used.

What is the amount of emissions released into the atmosphere? One of the most important elements in the thesis was to define the quantity of greenhouse gas emissions produced in a certain sector of rock construction project, would the production mechanism be altered and are there known methods that could be applied to minimize these emissions.

What are the mechanisms responsible for the majority of emissions? In the thesis the mechanisms were defined, and a model of the emissions was built to be applied in the process of emission calculations during the project development and contract calculations. The final product of the emission model is a One Click LCA summary,  which generates an estimate of the total emissions of the project.

What are the characteristics of the project affecting the quantity of the emissions and how? The research was done with a focus on underground spaces excavated for vehicle parking purposes and the results gained were used in a comparison with parking garages with concrete framework constructed aboveground.

The result of the study was founded on standardized method of life cycle assessment and lead to the conclusion that the excavation of a fictive tunnel would release an allocated emission of 18 kg CO2-eq/m3. Calculation was done by hand by using values acquired from environmental product declarations (EPD). Quantities used were then exported to web-based One Click LCA tool for reliability evaluation, which lead to the identical conclusion regarding the amount of emissions. Finally, post calculation data and quantities from an underground parking cavern and aboveground parking garage were analyzed and the amount of emissions from both cases was acquired. Result of the comparison made stated that allocated emissions released from underground parking cavern are slightly higher than from aboveground parking facility with corresponding capacity when the excavation phase and the construction phase are compared. The amount of emissions released during the complete life cycle of both cases will offer the solution to which of the parking systems is absolutely releasing less emissions.

Keywords rock construction, rock engineering, carbon footprint, underground blasting, emissions, sustainability in rock engineering

Author: Iikka Kronqvist
Supervisor: Leena Korkiala-Tanttu
Advisor: Zhongsen Li
Funding: Sitowise Oy ja Helsingin kaupunki

Short abstract:

Tässä työssä tutkittiin Helsingin Malmin lentokenttäalueelta otetuista häiriintymättömistä ja stabiloiduista savinäytteistä Bender element -mittausmenetelmällä määritettyä pienten muodonmuutosten leikkausmoduulia. Työssä selvitettiin eri sideaineiden vaikutusta pienten muodonmuutosten leikkausmoduuliin sekä häiriintymättömien savinäytteiden säilömisen vaikutusta. Lisäksi työssä olennaisena osana oli saatujen mittaustulosten pohjalta kehittää ja parantaa Bender element -mittausjärjestelyjä luotettavampien tulosten saamiseksi.