Fully Coupled Inelastic Site Response Analysis for 1986 Lotung Earthquake

Abstract

Two major earthquakes (M= 6.2 and M= 7) with different characteristics took place in the eastern coast of Taiwan in 1986 within a 4-month period. A test site at Lotung was located near the epicenters of the two quakes. The site was instrumented with three-dimensional (3D) surface and downhole accelerometer arrays and pore-pressure transducers embedded at depths from 3 to 16 m below the ground surface. Field investigation of the site, including sampling “undisturbed” soils, was carried out before the two events, and followed by a laboratory test program aimed at gaining detailed soil properties. Based on the available information, numerical analyses were performed using a fully coupled, multidirectional dynamic procedure incorporating a bounding surface hypoplasticity model. The calculated responses for the two different events showed equally reasonable agreements with the field records in both 3D acceleration and pore-pressure time histories. This paper reports the methodology of the analyses and presents the recorded data and calculated results.