Congratulations to Dr. Weiyuan Zhang!
Weiyuan Zhang, postdoctoral researcher in the section of Geo-Engineering, successfully defended his PhD thesis entitled “Centrifuge modelling of the behaviour of buried pipelines subjected to submarine landslides”, on 8 October 2020.
Weiyuan’s thesis presents a research effort on the investigation of the soil-pipeline interaction mechanisms of buried pipelines during subaqueous slope failures using the centrifuge modelling technique. In this research, slope failures under both drained condition and (partially) undrained conditions were simulated. The development of the soil failure mechanisms under both soil drainage conditions were visualized and analysed by the Particle Image Velocimetry technique.
For the tests under a drained condition, slope samples were made of dry sand with pipes buried at 5 different locations inside the slopes. The pipe burial position and pipe embedment ratio effects on the ultimate pressure during slope instability were studied. The results of these tests reveal that the slope angle and the pipe distance to slope crest play significant roles on the ultimate loads acting on the pipe.
For the tests under a (partially) undrained condition, very loose saturated sandy samples were made using the fluidization technique and were triggered to liquefy under monotonic loads. A novel test set-up comprised of a tilting system, a fluidization system and high speed, high resolution image capturing system was developed. A hypothesis of a static liquefaction triggering mechanism was proposed and the scaling law for pore fluid viscosity to simulate the onset of static liquefaction in the centrifuge was examined. The influence of pipe embedment ratio, pipeline structural stiffness, slope angle and shear strain rate on the pressures acting on the buried pipes during slope liquefaction was investigated.
Weiyuan’s thesis can be found here.
Weiyuan obtained his MSc degree in Geotechnical Engineering from Harbin Institute of Technology. After that, he worked at Shenzhen Investigation & Research Institute where he was responsible for the geotechnical design of slope protection structures. Thereafter, in 2015, he started his doctoral research in the section of Geo-Engineering, TU Delft. He has been working on the geotechnical design of suction foundations at SPT Offshoresince 2019. He worked as the on-site team leader and successfully installed the first wind turbine suction foundation in China. He is currently working as a (part-time) postdoctoral researcher in the Blue Piling project.