The Major Cause of Localization of Soil Liquefaction: Shear Banding

• Main Authors: TSAO,CHANG-CHI, 曹昌琦
• Other Authors: HSU,TSE-SHAN
• Format: Others
• Language: en_US
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/4zq542

博士 === 逢甲大學 === 土木水利工程與建設規劃博士學位學程 === 108 === Nowadays, the development of Internet has enabled people worldwide to access soil liquefaction images in earthquakes. These images clearly show that soil liquefaction only occurs locally in tectonic earthquakes. The actual soil liquefaction phenomenon can be examined to investigate whether the traditional soil liquefaction prevention methods adopted by scholars globally for a long time matches the actual needs in practice. To achieve the research purpose, this dissertation compares the definition, mechanism, factors, test methods, evaluation methods, disaster prevention methods, and design specifications of traditional soil liquefaction and localization of soil liquefaction. Then, the following observations are inferred: (1) according to the traditional definition of soil liquefaction, soil liquefaction occurs when the safety factor of soil liquefaction resistance is smaller than 1.0; (2) the traditional soil liquefaction mechanisms include flow liquefaction and cyclic mobility; (3) traditional soil liquefaction completely ignores the three essential constituent elements of localization of soil liquefaction in practice; (4) the traditional soil liquefaction potential distribution maps issued by the government show that all areas except the mountainous areas are potential areas for soil liquefaction, which accounts only for less than 1% of the total areas and therefore seriously deviates from the fact that soil liquefaction occurs only locally in the shear banding zone with brittle fracture. Based on the result-oriented feedback and improvement, it is found that the factors, test methods, evaluation methods, disaster prevention methods, and design specifications of traditional soil liquefaction only considers the secondary factors (ground vibration) of tectonic earthquakes, but excludes the main factors of tectonic earthquakes (shear banding). Therefore, all the research results are inconsistent with the actual needs of the localization of soil liquefaction. Therefore, by considering the actual needs of localization of soil liquefaction, the author proposes the factors, test methods, evaluation methods, and disaster prevention methods for localization of soil liquefaction, with a purpose of correcting the research direction to the localization of soil liquefaction and making all the results of future researches comply with the actual needs of the localization of soil liquefaction. Based on the conclusion of this dissertation, the author suggests that the government should pay attention to the fact that the traditional definition for soil liquefaction deviates from the localization of soil liquefaction, and they should redraw the distribution maps of potential areas of localization of soil liquefaction as well as revise the disaster prevention methods and design specifications of localization of soil liquefaction. Only in this way can the potential distribution maps and the soil liquefaction prevention methods meet the needs in practice.