Vacant doctoral student position: piling

The Swedish Transport Administration and SBUF have decided to fund our research project ”Piling in soil with high boulder content: systematic study of pile refusal in different soil types”. We are therefore searching for a doctoral student for this project. Apply for the position here  during September 2021.

Piling is a frequently used foundation method, but driven piles often encounter boulders during driving in till or esker material. This can cause structural failure to the pile, which in turn can create a need to re-design the pile group, causing delays and additional costs. However, it is challenging to assess the probability of pile refusal and existing assessment tools are simplistic. Consequently, the construction industry often sees claims and disputes related to this issue. The purpose of the research project is to develop a systematic methodology for assessing the risk of pile refusal. The methodology shall be based on input from common ground investigation methods and allow assessment of this risk in different soil types and for different pile driving equipment. At the end of the project, recommendations are to be presented for how piles can be driven cost-effectively while minimizing delays and material use.

The doctoral student’s work tasks include:

1. case studies of whether the proportion of incorrectly driven piles is related to specific ground properties, boulder size and their spatial variation,
2. development of calculation models that describe how the pile is affected as it hits a boulder, using both analytical methods and numerical methods, such as the finite element method,
3. development of a probabilistic model that describes how uncertainty regarding the actual ground properties and boulder size affects the calculated risk for getting incorrectly driven piles,
4. planning of field measurements of pile behaviour during driving,
5. writing scientific articles to be published in international journals and conferences,
6. taking postgraduate level academic courses on research methodology, geotechnical engineering, and scientific writing,
7. being teaching assistant in geotechnical engineering courses on bachelor or master level.

The project will be executed in close collaboration with the Swedish construction industry. The doctoral student will have his/her main workplace on KTH’s main campus (Valhallavägen) and be supervised by Dr. Johan Spross (KTH Division of Soil and Rock Mechanics; main supervisor) and Dr. Anders Beijer Lundberg (expert in piling at ELU konsult; co-supervisor). The doctoral student will also be supported by foundation engineering experts at the construction and civil engineering company PEAB.

The project is currently funded for doctoral studies leading to a licentiate degree . We intend to apply for additional funding to cover also the remaining two years to a PhD degree, if the project outcome is satisfactory and the doctoral student wishes to continue toward the PhD degree.