Doctoral theses of the School of Engineering at Aaltodoc (external link)
Doctoral theses of the School of Engineering are available in the open access repository maintained by Aalto, Aaltodoc.
Public defence, Geoengineering, MSc Maarit Saresma
Depositional environments control the occurrence of sulphide-bearing fine-grained sediments and the variability of offshore seabed strength. Public defence from the Aalto University School of Engineering, Department of Civil Engineering
When
–
Where
Otakaari 3, Espoo, auditorium F239a
Event language(s)
English
In this event, we are committed to Aalto University’s principles for a safer space.
Title of the thesis: Characteristics, classification and engineering-geological properties of fine-grained sediments in the capital region of Finland
Thesis defender: Maarit Saresma
Opponent: Prof. Tim Länsivaara, University of Tampere and Senior Research Fellow Atko Heinsalu, TalTech, Estonia
Custos: Professor Emerita Leena Korkiala-Tanttu, Aalto University School of Engineering
Fine-grained sediments in the Baltic Sea coastal region are often sulphide-bearing and soft, making them challenging for land use and construction planning. Predicting the occurrence of these sediments is critical for enabling sustainable construction and cost-effective solutions.
While acid sulphate soils have been widely mapped, the role of depositional environments in predicting the occurrence of sulphide-bearing fine-grained sediments has received far less attention. This research created and classified paleotopographic settings and studied the statistical association between sediment environmental and material properties and the occurrence of sulphide. The findings revealed the versatile terrain characteristics of the ancient Baltic Sea basin and indicate that sulphide-bearing sediments are particularly associated with narrow depressions, in which thick layers of organic-rich fine-grained sediments have deposited after deglaciation. The study shows that geospatial analysis of the depositional environments of fine-grained sediments can significantly improve the prediction of sulphide-bearing sediments.
This research also examined methods for investigating soft seabed sediments. Due to recent developments, fast and efficient investigation techniques are needed to support the offshore construction planning. The study evaluated the applicability of the free fall cone penetrometer for estimating the in situ undrained shear strength of fine-grained sediments and identified characteristic strength profiles for different sediment units in soft seabed environments. The method proved promising for interpreting seabed strength properties, particularly when combined with geophysical surveys, thereby supporting regional-scale planning and development in offshore areas.
Key words: Fine-grained sediments, paleotopography, sulphide, free fall cone penetrometer, undrained shear strength
Thesis available for public display 7 days prior to the defence at Aalto University's public display page.
Contact information: maarit.saresma@aalto.fi, maarit.saresma@gtk.fi
Doctoral theses of the School of Engineering
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