• Journal of the Korean Geotechnical Society
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• v.38 no.3
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• pp.5-16
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• 2022

Ground in extremely cold and hot regions can sink by various environmental factors. Ground settlement can generate the negative skin friction to pile shaft, increase the base load of pile, and cut the stability of the pile. This study proposed a member responding ground deformation which can be inserted inside the pile. The member slightly compresses according to the ground settlement to reduce the negative skin friction. As the member materials, this study considered spring and spring-dashpot. To assess the ability of the member, the present research performed model tests for piles with or without the member within settled ground. In the model tests, the base load, total shaft resistance, and horizontal earth pressure were monitored and analyzed. Experimental results show that the pile with spring member can reduce the negative skin friction under small settlement conditions whereas it acts similar to the pile without the member under large settlement conditions as the spring was no longer compressed. However, the pile with the spring-dashpot member can reduce the negative skin friction continuously upon the ground settlement as the dashpot delays the load transfer to the spring and locates friction force on the unloading path.

• Journal of Korea Water Resources Association
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• v.54 no.6
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• pp.407-418
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• 2021

In this study, the two-dimensional flow model, Nays2DH, and driftwood dynamics model were combined to analyze the flow and driftwood behavior depending on the characteristics of the inflow of driftwood and the length of the driftwood stem. In particular, the Dashpot-spring model was added to the driftwood dynamics model to simulate the collision motion of the driftwood, and the wood jam characteristics by the collision of the driftwood were compared. As a result of the simulation, the pass rate of the obstacle section, the travel distance of wood jam, and the mean position of the wood pieces were respondent sensitively by the length of the driftwood stem, but the cohort size of the driftwood supply was insignificant excepting for the pass rate. Through this study, we could understand the interaction between hydraulic structures and driftwood, and through this, it is believed that it will be helpful in establishing a durable maintenance plan for hydraulic structures by predicting the transport and jam formation phenomena of driftwood in advance.