The Department Mechanics of Solids, Surfaces & Systems (MS3), part of the faculty of Engineering Technology (ET) is currently seeking a PhD student in the area of modelling friction in crushed rock grains (gouge) in reservoir faults. The work will be done in the Surface Technology and Maintenance (SEM) group, where we work on topics related to surfaces and interfaces, damage and failure mechanisms, e.g. frictional failure in faults leading to earthquakes.

Earthquakes reflect the phenomenon of sudden slip when the frictional strength of faults in the Earths crust is overcome. This project seeks to understand the physical processes controlling this sudden failure through numerical modelling and lab experiments and applying the results to acquire large-scale models for earthquakes caused by gas extraction, geothermal energy production and subsurface storage. Gaining deeper knowledge of frictional mechanisms in faults at different length scales will help improve forecasting of earthquakes and other subsurface phenomena, caused by growing human intervention.

Fractures and discontinuities in rocks, i.e. faults in natural gas reservoirs are typically filled with crushed rocks grains called gouges. In a depleting gas reservoir, stresses on pre-existing faults result in fault reactivation and slip, thereby inducing seismicity. Understanding the friction between the gouge-grains in key to modelling fault slip. Frictional phenomena in individual gouge-grain contact can be experimentally simulated at the microscale as the relevant scale where physical frictional interactions take place. Using results from single grain experiments, a physical basis will be formulated for friction phenomena in microphysical and numerical granular models for fault-gouges.

The aim of the project is to develop physics-based friction models for fault contacts following a bottom-up approach and use these models to compute fault slip resulting in induced seismicity due to subsurface activities. The objectives of the PhD research, to accomplish the main aim will be:

O1. To develop friction laws for single-grain contacts in crushed fault-rock gouges using microscale sliding experiments and numerical models.

O2. To implement these micro-scale friction laws in numerical models developed to compute friction in fault-gouges (dm-scale granular-assembly).

• MSc (Masters) degree inMechanical Engineering or equivalent, preferably with a background in tribology
• Skills in granular mechanics (particle modelling) and/or experimental techniques like atomic force microscopy is an advantage
• You are an excellent researcher, eager to learn and to improve;
• You thrive in a collaborative environment;
• Your interpersonal skills as well as English language skills are excellent.

The UT provides a dynamic and international environment, combining the benefits of academic research with a topic of high industrial relevance, excellent working conditions, an exciting scientific environment, and a green and lively campus. We offer:

• A full-time 4-year PhD position;
• We provide excellent mentorship and a stimulating international research environment with excellent facilities;
• You are offered a professional and personal development program within Graduate School Twente;
• A starting salary of €2.434,- gross per month in the first year and a salary of €3.111,- in the fourth year gross per month;
• A holiday allowance of 8% of the gross annual salary and a year-end bonus of 8.3%;
• A solid pension scheme;
• Minimum of 29 holidays per year in case of fulltime employment.