PhD position at Utrecht University on understanding long term viscous and short term elastic soft soil deformation leading to land subsidence

Within the framework of the joint NWA-ORC-programme Living on Soft Soils: Subsidence & Society project of Utrecht University, TUDelft, Wageningen University and Research, Deltares Research Institute, TNO, Wageningen Environmental Research and Utrecht University, Utrecht University is seeking a motivated PhD candidate to work on this collaborative research programme.

Programme description

The threat of land subsidence, the knowledge hiatus on process-interplays causing it, and lacking mid- to long-term coping strategies, ask for an integrated research programme that addresses the issue of land subsidence in a holistic way, whereby insights about physical-chemical-biological system functioning, development, evaluation and implementation of measures as well as an assessment of their governance and legal implications co-evolve. The overall aim of our programme is to develop an integrative approach to achieve feasible, legitimate and sustainable solutions for managing the negative societal effects of land subsidence, connecting fundamental research on subsidence processes to socio-economic impact of subsidence and to governance and legal framework design.

The programme consists of four scientific work packages:

WP1: Measuring and monitoring of land subsidence

WP2: Land subsidence mechanisms and associated greenhouse gas emissions

WP3: Impact analysis of land subsidence

WP4: Measures and governance approaches to cope with land subsidence

The programme is funded by and contributes to the Dutch Research Agenda – Research along routes by consortia (NWA-ORC) aiming to stimulate research and innovation focused on the NWA routes, designed and implemented by interdisciplinary consortia spanning the entire knowledge chain, in which relevant social partners (Deltares Research Institute, TNO, Wageningen Environmental Research, NAM, Tauw BV, Sweco, Municipality of Gouda, Platform of Soft Soil Municipalities, Province of Utrecht, WDOD, HDSR, STOWA, Ministry of the Interior and Kingdom relations, Ministry of Infrastructure and Water Management) are also represented.

PhD-project WP2.2 will study coeval short term (elastic response) and long term (viscous) soft soil deformation. Existing and recent measurements show a complex time dependent volumetric behaviour of soft soils under changing conditions of e.g. groundwater level and soil moisture. In geomechanical laboratory measurements, long term slow viscous behaviour (creep) is observed. In the case of peat and very organic clays, a mechanistic explanation of this viscous behaviour is currently lacking. This PhD project aims at providing a mechanistic explanation for both long and short term geomechanical behaviour. This understanding will feed into concurrent projects that focus on the numerical modelling of land subsidence.

On a set of representative samples from the case study areas, MRI-scanning, Electron microscopy and experimental lab tests using gravitational and centrifugal force setups will be used to determine the effective pore space in different states of deformation. Also data from large scale field tests, both archived and foreseen, may be used.

This project will be executed in the Global Change Geomorphology group (Dr Erkens, Dr Stouthamer) in close cooperation with Deltares Research Institute.

Various national and international networks supporting land subsidence science exist of which the PhD candidate will be part. Interaction is foreseen with fellow researchers of the Living on Soft Soils programme; with geodesy, numerical modelling and soil biology Researchers within UU, TU Delft, WUR, WEnR, TNO – Geological Survey of The Netherlands, Deltares Research Institute.