Dynamic Simulation of the Reinforced Slope Failure at Chi-Nan University During the 1999 Chi-Chi Earthquake - Reinforced Soil Engineering: Advances in Research and Practice - page 458

Figure 4 Failure of the reinforced slope during construction in 1995.

3 CHARACTERISTICS OF THE CHI-CHI EARTHQUAKE

The Chi-Chi earthquake with a record high of 989 gal in acceleration (E-W
direction) hit the central part of Taiwan on September 21, 1999. Seismic
information recorded at the Nan-Kuan elementary school, which is the closest
seismograph station to the site, in Pu-Li shows that the peak accelerations for
north-south east-west, and vertical directions are 368.4, 585.94, and 270.18 gal,
respectively. The time history recorded at this station is shown in Fig. 5 .

4 GEOLOGICAL CONDITIONS AT THE SITE

The site is around the rim of Pu-Li basin, a geographic center in Taiwan. The
geology at the site is composed of a thick layer of gravel mixed with soil
underlain by sandstone embedded with shale. The gravel stratum, however, is
embedded with a thin layer of hard clay at a given depth based on the boring
investigation. The geological profile at the site of the reinforced slope is shown in
Fig. 6 . Descriptions and engineering properties of the geological deposits at the
site up to a depth of 80 m are as follows:

1. Top soil: brown; tens of centimeters of 2m in thickness.