Per Gunnvard

Per Gunnvard is a Civil Engineer with an MSc in Soil and Rock Mechanics from Luleå University of Technology in Luleå, Sweden. He is now a PhD student at the Division of Mining and Geotechnical Engineering at Luleå University of Technology. His research includes physical, numerical and analytical modelling based on physical data from field measurements, with a focus on piled embankments, timber piles and geogrids.

The doctoral study has been financed by the Swedish Transport Administration via the Swedish joint-research group Branschsamverkan i grunden (BIG) within the framework of the projects below. The Swedish Transport Administration introduced in TK Geo 13 a recommendation for light bank piling with wooden piles of untreated timber (also called Norrlandspålning) as an alternative to the typical bank piling. Wooden piling is not only more environmentally friendly than concrete and steel piling, but also usually cheaper and thus a more sustainable solution. However, the dimensioning requirements still involve relatively large resource consumption, hence the question of an optimization of the method was raised.

Research project 1: B2015-21 Optimal timber piling design

• Objective: clarify the load distribution in timber-piled road embankments as well as evaluate and optimize the current recommendation for timber-piled road embankments with a focus on the pile group.
• A theoretical analysis of the structure's function was carried out through 3D finite element analyses. Comparison with well-established analytical models.
• The project has clarified much of the load distribution that was not previously known for timber-piled embankments. The final report provides a detailed example of both numerical and analytical calculations for the design of timber-piled embankments.

Research project 2: A2020-17 The Use of Geosynthetic Reinforcement in Light Embankment Piling

• Continuation of research project B2015-21 Optimal timber piling design.
• Objective: optimize the use of geosynthetics in timber-piled embankments.
• Instrumentation of timber-piled road section (E4 Råneå, Norrbotten) and 3D finite element analyses.
• The instrumentation along the route means that real data has been analyzed and evaluated. The data has, among other things, contributed to increased knowledge and the possibility of calibration in element modelling. The results of the simulations give strong indications of an object-adapted design that is more flexible and resource-efficient than the current standard.

Group of timber piles and geogrid-reinforced embankment filling. Photo: Daniel Hugh