Geoengineering master's theses

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

Abstract:

Tässä diplomityössä tutkitaan kahdella eri siipikairauslaitteistolla mitattuja hienorakeisten maalajien suljettuja leikkauslujuuksia. Tutkimuksen rahoitti Espoon kaupungin geotekniikkayksikkö. Vertailtavina laitteina ovat Espoossa pitkään käytössä ollut Nilcon-mallinen mekaaninen siipikairauslaitteisto sekä keväällä 2020 hankittu uudempi ja osin automatisoitu sähköinen siipikairauslaitteisto Geomachine GM4W. Siipikairauksia on tutkimusta varten tehty Espoossa neljällä eri alueella loka-joulukuussa vuonna 2020. Alueet olivat Finnoonpuro, Kalajärvi, Monikonaukea sekä Tapiolan urheilupuisto. Alueiden valintaan vaikuttivat savikon paksuus, laajuus ja syntyhistoria.

Kullekin alueelle tehtiin kahdesta kolmeen vertailevaa tutkimusparia, joissa siipikairaus suoritettiin kummallakin laitteella. Siipikairauksilla tehtiin tutkimuksen yhteydessä yhteensä 216 havaintoa leikkauslujuudesta kaikkiaan 21 eri pisteessä. Kahdessa tutkimuspisteessä vertailuun käytettiin Espoon pohjatutkimusrekisterissä olevia, aiemmin tehtyjä siipikairaustuloksia. Siipikairausten lisäksi tutkimuspaikoilta otettiin häiriintymättömiä maanäytteitä ja tutkittiin laboratoriossa 70 maanäytettä. Näistä pyrittiin määrittämään maalaji rakeisuuden perusteella, vesipitoisuus, huokoisuus, tilavuuspaino ja humuspitoisuus. Lisäksi määritettiin leikkauslujuus kartiokokeella niistä näytteistä, joista se oli mahdollista.

Vertailussa havaittiin, että Nilcon-laitteella mitatut leikkauslujuudet olivat useammin suurempia, kuin GM4W:llä mitatut leikkauslujuudet. Leikkauslujuuksien ero vaihteli välillä 0,1…23,9 kPa. Suurimmat vaihtelut selittynevät maaperän heterogeenisuudella, mutta myös kairaustyön suorittamisessa ilmeni eroja. Lisäksi nykyisen Nilcon-laitteiston käyttö ei mahdollista siipikairausohjeiden täysimääräistä noudattamista. Yhtenä suurimmista tekijöistä on siiven pyöritysnopeus ja sen vakiona pitäminen mittauksen aikana. Nykyisellä Nilcon-laitteistolla ei myöskään voi käyttää suojaputkia kairaustankojen ympärillä, jotka poistaisivat maaperän aiheuttaman tankokitkan.

GM4W:n todettiin olevan mittauslaitteena luotettavampi, koska mittaukset ovat toistettavampia ja ohjeiden mukainen mittaustilanne helpommin saavutettavissa. Alkuasetusten määrittämisen jälkeen mittaustulokset saadaan GM4W:stä suoraan sähköisessä muodossa eikä niitä tarvitse erikseen tulkita, kuten Nilconia käytettäessä.

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

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

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

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

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

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.