Modelling the non-linear site response at the LSST down-hole accelerometer array in Lotung: Fid-Bau Portal

Modelling the non-linear site response at the LSST down-hole accelerometer array in Lotung

Elia, Gaetano / Rouainia, Mohamed / Karofyllakis, Dimitrios / Guzel, Yusuf

AbstractDown-hole array observations are extremely useful to investigate site amplification effects and to validate numerical modelling techniques for site response. In this paper the ground response of the Lotung experiment site (Taiwan), measured along a down-hole accelerometer array during a weak and a strong motion event, is simulated using different numerical techniques of increasing level of complexity: 1) a simple equivalent-linear visco-elastic procedure, 2) a total stress time-domain scheme using a pressure-dependent hyperbolic model and 3) a fully-coupled approach implementing an advanced elasto-plastic soil model. The numerical models are calibrated against resonant column data and in-situ cross-hole measurements. The two horizontal components of the input motion are applied separately at bedrock level. The results of the simple and advanced numerical simulations are compared with the down-hole motions recorded in-situ during the investigated seismic events in terms of acceleration time histories and response spectra. The comparison between in-situ measurements and predicted results highlights the well-known limitations of the frequency-domain technique. It also shows some improved predictive capabilities of the total stress time-domain scheme and demonstrates the excellent performance of the fully-coupled advanced non-linear approach.

Highlights•The seismic response of the LSST site is studied with three numerical techniques.•The models are calibrated against the same set of laboratory and in-situ data.•A good agreement with array data is obtained by fully-coupled non-linear analyses.•The natural variability in soil properties should be considered in advanced models.