ABSTRACT

This paper examines the liquefaction potential of a site at the Chang-Hwa Coastal Industrial Park. The site is on a reclaimed land that was created by hydraulic filling. The liquefied phenomenon of this site was taken place in the 1999 Chi-Chi earthquake, Taiwan. After the earthquake, dynamic compaction was performed to mitigate the liquefaction hazards at the site. After the completion of ground improvement work, additional site exploration using CPT was carried out. The in situ test data obtained from the liquefied areas before and after the ground improvement, are analyzed, and the results are reported.

INTRODUCTION

Due to the heavy population density and limited land resource, several industrial parks were developed along the west coastal area in Taiwan. Those parks are located at on the reclaimed land that was created by hydraulic filling. Taiwan is located at the seismic fire ring of the Pacific Ocean. Earthquake was frequently occurred in Taiwan. The reclaimed land is characterized with loose soil layer and high ground water level. There is a high potential of liquefaction at the reclaimed land. Soil liquefaction in an earthquake can cause enormous economic losses. Remedial measures are often conducted and treated as an important project at the high liquefaction potential site. Dynamic compaction (DC) is one of the most commonly used techniques for the ground improvement at the reclaimed land. Densification of soils by heavy tamping or dynamic compaction (DC) has long been used as a remedial measure against soil liquefaction and other geohazards (Handy 2013; Feng et al. 2015).

The Automotive Research and Testing Center (ARTC) was planned to be constructed in a site located at the Chang-Hwa Coastal Industrial Park. The Park is located in Chang-Hwa, on the west coast of central Taiwan. The site selected is at a reclaimed land that was created by hydraulic filling. Moreover, the site was susceptible to having the issue of the liquefaction and was suggested to apply the DC for the ground improvement. The main pounder used in the DC weighed 25 tons, which had a base area of 3 m2 and a drop height of 20 m. The ironing tamping after the main pounding used a smaller ponder, which weighted 12 tons and had a base area of 6 m2 and a drop height of 10 m. Before the completion of ground improvement work, a strong earthquake (Chi-Chi earthquake, Mw = 7.6) attacked central Taiwan on the September 21, 1999. The epicenter of the Chi-Chi earthquake is about 50 km away from the site in which experienced a major ground shaking from the Chi-Chi earthquake. Sand boils were observed at this site when the Chi-Chi earthquake hit. After the completion of the ground improvement, additional site exploration using CPT was conducted in the liquefied area. This paper aimed to reexamine the liquefaction potential at the liquefied area after the completion of ground improvement by the DC.

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