The Chi-chi Earthquake of 1999, with a Richter magnitude of 7.3, was the most damaging earthquake of the century that had occurred in inland Taiwan. Significant liquefactions were evident in many places on the west plain of the
island as a result of the shaking, in which the alluvial deposits of the Chou-swei River Fan had been suffered the most.
The current study was initiated by collecting geological information of the area, including Changhua and Yunlin Counties. A total of 1100 effective borehole logs was collected and setup in a database. Three liquefaction
analysis methods were employed, which included Modified Seed’s Method (Seed 和Idriss 1971；Youd et al. 2001), Tokimatsu & Yoshimi’s Method (1983), and the new version of Japan Railroad Association’s Method (NJRA 1996). The study adopted the peak ground acceleration (PGA) data recorded in several locations on the alluvial plain during the Chi-chi earthquake. Liquefaction potentials were evaluated based on a weighing procedure proposed by Iwasaki (
1982). The post-shaking settlements were also estimated based on the method of Ishihara (1993). For comparison of the accuracy and suitability of the simplified methods adopted in the current study, a cyclic triaxial test program was conducted on Shelby tube samples collected from Tounan Town, Yunlin, a site where serious liquefactions had occurred during the 1999 shaking. The aim of this study was to evaluate the liquefaction resistance of a local sand from Tzo-sui River, injected by a cement and sodium silicate solution to simulate the effect of a low-pressured grouting. A series of
cyclic triaxial testing was performed.
