Experimental & numerical simulation of soil boundary conditions under dynamic effects

Qaftan, O; Weekes, L; Toma-Sabbagh, TM; Augusthus Nelson, L

Abstract

When conducting earthquake simulation tests, one of the main concerns is the modelling of boundary effects created by artificial boundaries of a soil model container. The function of this soil container is to hold the soil in place during the excitation and to provide confinement. In reality, the soil is unbounded. However, the ideal soil container should simulate the free field soil behaviour as it exists in the prototype, by minimising the boundary effects. The key parameter in the design of the container is to satisfy the dynamic response of the adjacent soil. In this paper, the results of physical tests are compared with numerical simulation results. A cylindrical container (1 m in diameter and with 0.6 m in height of soil) with a flexible curved membrane was built and tested on shaker table. The harmonic loadings and artificial earthquake time history excitations were applied at the base of soil container. The responses of soil at different elevations were measured during the tests using accelerometers and displacement transducers.
To obtain more realistic results and understand the underlying mechanism, soil boundaries with flexible members (thin wall shell elements) was used to represent the membrane part of the soil container in FE implicit analysis. In all cases, the numerical output results were compared with measured values for different physical parameters. It was found that the soil container with specific design and dimensions has an insignificant effect on the soil response during the shaking events.

Citation

Qaftan, O., Weekes, L., Toma-Sabbagh, T., & Augusthus Nelson, L. (2018, June). Experimental & numerical simulation of soil boundary conditions under dynamic effects. Presented at 16th European Conference on Earthquake Engineering (16ECEE), Thessaloniki, Greece

• Presentation Conference Type: Other
• Conference Name: 16th European Conference on Earthquake Engineering (16ECEE)
• Conference Location: Thessaloniki, Greece
• Start Date: Jun 18, 2018
• End Date: Jun 21, 2018
• Acceptance Date: Mar 7, 2018
• Deposit Date: Apr 24, 2018
• Publicly Available Date: Jun 22, 2018
• Publisher URL: http://www.16ecee.org/
• Additional Information: Event Type : Conference