Master's Thesis

This thesis explores the development of a pavement health monitoring system using embedded fibre optic sensors to capture and analyze vibration data. By integrating Distributed Acoustic Sensing (DAS) technology within pavement layers, the study aims to detect early signs of structural degradation, such as cracking, delamination, or subsurface voids, through real-time vibration pattern analysis. The research focuses on correlating traffic-induced vibrations with pavement condition, employing signal processing techniques to identify anomalies indicative of wear or damage and employing a numerical pavement model for its quantification.

This project focuses on the development of evaluation methods for fibre optic vibration measurements in dynamic pile tests. The goal is to enable precise assessment of integrity, load transfer mechanisms, shaft friction, and end bearing behavior exploiting the advantageous nature of internal measurements compared to traditional sensors. The project will develop data interpretation techniques, including inverse analysis and numerical modeling, to translate fibre optic measurements into meaningful geotechnical insights.  

There are several highly specialized applications of asphalt concrete in hydraulic engineering. One of them is its use as watertight layer, lying on the water-facing side of earth- and rockfill dams. Yet, the behavior of such asphalt facings under seismic loads is not well researched. This master thesis focuses on the experimental determination of the plasticity parameters of the asphalt concrete at different temperatures and deformation rates. The final goal is to fit the parameters to a constitutive model and analyze its behavior in element tests.

This thesis aims to extend an existing constitutive model for lake sediments to incorporate viscous (time-dependent) effects, based on the results of an extensive laboratory testing campaign. The implementation of the constitutive model, as well as the parameter calibration, will be verified through numerical simulations of laboratory tests using the Finite Element Analysis software ABAQUS. In a subsequent phase, the model will be applied to boundary value problems—such as foundation or excavation scenarios—to investigate the influence of viscous effects.

Lake Zurich has experienced several well-documented subaqueous landslides, triggered either by seismic activity or human interventions. This thesis aims to enhance the understanding of the initial slope conditions and the role of hydraulic factors in failure initiation. The insights gained will contribute to improved hazard assessment and the design of mitigation measures, including coastal backfills. The study will involve numerical simulations using the Finite Element Method to analyze a combined shore collapse and subaqueous landslide event. The model will be informed by data from field investigations, laboratory tests, and historical reports of past failure.

In Switzerland, critical infrastructure is often located near lakes or on land reclaimed from them—areas underlain by soft lake sediments with low stiffness and strength. Numerous failure cases have been reported during or shortly after the construction of such infrastructure. Although it is well documented that lake sediments can fail during seismic events, as seen in various subaqueous landslides, the constitutive behavior of these sediments under seismic loading remains largely unexplored. This thesis aims to address this knowledge gap through a series of cyclic undrained triaxial tests on lake sediment samples in the laboratory. The experimental results will be used to gain deeper insight into the seismic response of lake sediments. Furthermore, documented failure cases will be re-evaluated in light of the findings, and implications for the seismic safety of existing structures will be assessed.