| Summary: | 碩士 === 國立宜蘭大學 === 建築與永續規劃研究所碩士班 === 96 === When an earthquake occurs, a site containing saturated loose sand layers may induce soil liquefaction. As a consequence, ground may sustain subsidence and lateral spread, and buildings, bridges and underground pipes may suffer damage. This may result in people casualty and economy losses. Therefore, the assessment of soil liquefaction is an important topic. In this study, we evaluate methods for soil liquefaction assessment and use sites in Luodong Town, Yilan County as case studies to explain the subjects.
In this study, we divide the assessment of soil liquefaction at a site into three aspects. First, in order to quickly assess the status of liquefaction at a site, we ignore earthquake effect and evaluate the liquefaction susceptibility at a site. We divide the liquefaction susceptibility into four categories and establish rules for each category. Second, to consider earthquake effect on soil liquefaction, we define a simulated earthquake based on seismic sources that may affect the site, and estimate the peak ground acceleration at the site caused by this simulated earthquake. We then calculate the liquefaction potential index and determine the degrees of liquefaction at a site. Third, to design a building at a site, we need to assess the liquefaction potential at a site following the procedure specified in the current building code. In the building code, it is specified that the liquefaction potential at a site must be evaluated for three levels of earthquakes (small/medium earthquake, design earthquake, and maximum considered earthquake). In this study, we examine the appropriateness of the specification for small/medium earthquakes using the seismic date from earthquakes occurred in the Yilan area.
Many extended engineering systems, such as a road system and a water delivery system, are spread into a large area. For such a system, it is needed to establish a technique to assess soil liquefaction in a large area. In this study, we offer a method for mapping the liquefaction susceptibility or liquefaction potential in a large area. In this method, we first compile the boring logs data for a study area. Using these boring logs, we assess liquefaction susceptibility or liquefaction potential at the sites where boring logs are available. We then use GIS technique to generate a liquefaction microzonation map. The liquefaction microzonation map can be used as resources for engineering planning or disaster prevention planning.
|
|---|
