| Summary: | 碩士 === 國立宜蘭大學 === 土木工程學系碩士班 === 95 === The 1999 Chi-Chi earthquake (with Richter magnitude 7.3) caused terrible damages in the whole island. The soil liquefaction problem is thus become a hot topic again after the earthquake inside the island and all over the world. Ilan area is located between the east and the northeastern earthquake regions of Taiwan. Langyang Plain is a sedimentary deposit from several rivers. As a result, the subsurface conditions of the Lanyang Plain generally contain several layers of loose uniform grained soils. Furthermore, the groundwater table of the whole Lanyang Plain is fairly close to the ground surface. Together with the high probability of earthquake occurrence in this area, soil liquefaction phenomena need to be carefully investigated.
This research describes the approach and the evaluated results of the potential for soil liquefaction of the Ilan area using the engineering geological data as a beginning. The evaluation of the soil liquefaction potential is based on the individual borehole data with and without considering the degree of earthquake attack. The levels of evaluating soil liquefaction potential in this research can be describes as three parts.
The first part: Since the soil condition is a very important factor for evaluating the soil liquefaction potential. It is reasonable to evaluate the soil liquefaction potential preliminarily by simply using the properties obtained from the soil investigation. This research is thus carried out for the approach of preliminary assessment without considering the effect of earthquake attack.
The second part: Establishing a maximum ground acceleration situation to calculate the soil liquefaction potential value. Besides, assuming a liquefaction potential value to back-calculate the maximum ground acceleration.
The third part: Performing simulation of soil liquefaction potential caused by possible scenario earthquakes. Taking the advantages of geographic information system (GIS), the evaluated results can be connected to each other by the spatial analysis modulus to obtain the map of soil liquefaction potential. The maps of soil liquefaction potential can be used to provide information for formulating disaster reduction strategy so that damages and losses from earthquake hazards could be mitigated.
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