Earthquake Induced Soil Liquefaction: Influence of Temperature and Dissolved Gas

地震诱发土壤液化：温度和溶解气体的影响[j]：教授，博士，体育，土木工程。本研究的目的是确定温度和溶解气体如何影响：1)地震诱发液化的最大距离、严重程度和时间；2)诱发液化的循环应力比（CSR）。研究将包括详细的文献检索、统计分析、实验室测试程序和理论建模，以确定温度和溶解气体对地震诱发液化和液化后触发反应的影响。在液化层之上，地基开裂、沉降、横向扩散和地基破坏是常见的现象。一些研究人员使用了大量的液化历史案例和实验室测试，以1)预测离断层带的距离上限，以及2)CSR诱发液化。然而，文献中报道的研究都没有将地温作为一个变量。大多数关于液化的实验室研究都是在室温（约20摄氏度）下进行的，而据报道，地震引起的液化的估计地面温度低至约2摄氏度（阿拉斯加），高至27摄氏度（印度、委内瑞拉和墨西哥）。已知液态水的几种物理性质在这个温度范围内会发生变化。P.I.对全球50多次地震进行的有限统计分析表明，温暖地区报告的最大液化距离是寒冷地区报告距离的两到三倍。文献还表明，地震引起的液化产生了更高、更有能量的沙和水，形成了更大的沙吹坑，在温暖的气候条件下比在寒冷的气候条件下逸出更多的气体。更广泛的影响：该研究旨在增加对液化的科学理解，并通过将地温和溶解气体作为变量来改进当前岩土工程液化分析和预测的最新技术。研究结果应有助于公共安全，提高工程设计和施工的经济性，并教育学生进行地震研究和分析。这些结果也可能影响地震学家（另一个研究领域）进行的地震学研究，他们调查古液化在地震风险研究和桩基础横向扩散和相关侧压力的工程研究中的应用。研究结果的发表可能会引发大量的现场、实验室和离心机测试和理论建模，以更好地理解这些影响。该提案将培养地震工程领域的研究生，并鼓励本科生和代表性不足的学生参加。智力优势：在评估液化时考虑了许多参数，但温度或溶解气体不在其中。pi的初步分析表明，在其他条件相同的情况下，液化可能在温暖的气候中更为普遍。正因为如此，无论是从理解这一过程的知识价值，还是从经济和公共安全的角度来看，温度依赖的概念都值得研究。

Earthquake Induced Soil Liquefaction: Influence of Temperature and Dissolved GasP.I.: Professor Wayne A. Charlie, PhD, PE, Civil Eng. Dept., Colorado State UniversityRESEARCH ABSTRACT The objectives of this research are to determine how temperature and dissolved gas influence 1) the maximum distance, severity, and timing of earthquake-induced liquefaction, and 2) the cyclic stress ratio, CSR, inducing liquefaction. The research will include a detailed literature search, statistical analysis, laboratory testing program, and theoretical modeling to determine the influence of temperature and dissolved gases on earthquake-induced liquefaction and post-triggering response of liquefied sandy soil. Ground cracking, ground settlement, lateral spreads and foundation failures commonly occur above liquefied layers. Several investigators have used extensive case histories of liquefaction and laboratory tests to 1) predict upper limits of distance from the zone of faulting, and 2) the CSR inducing liquefaction. However, none of the studies reported in the literature has included ground temperature as a variable. Most laboratory studies of liquefaction have been conducted at room temperature (about 20 degrees C) while earthquake-induced liquefaction has been reported where estimated ground temperatures are as low as about 2 degrees C (Alaska) to as high as 27 degrees C (India, Venezuela and Mexico). Several physical properties of liquid water are known to vary over this temperature range. Limited statistical analysis conducted by the P.I. on over 50 worldwide earthquakes indicates that warmer regions have maximum distances of reported liquefaction two to three times the distances reported in cooler regions. The literature also suggests that earthquake-induced liquefaction produces sand and water blows which are much higher and more energetic, larger sand blow craters, and gases which escapes in larger quantities in warmer climates than in cooler climates. Broader Impacts: The research is designed to increase the scientific understanding of liquefaction and to improve the current Geotechnical Engineering state-of-the-art of liquefaction analysis and prediction by including ground temperature and dissolved gas as variables. The results should contribute to public safety, improvement in economy of engineering design and construction, and educate students in earthquake research and analysis. The results may also impact seismological studies conducted by seismologists (a different field of research) who investigate the use of paleoliquefaction for seismic risk studies and engineering studies of lateral spread and associated lateral pressures on pile foundations. Publication of the research results may trigger substantial field, lab, and centrifuge testing and theoretical modeling to better understand these effects. The proposal will train graduate students in the area of earthquake engineering and undergraduate and underrepresented students will be encouraged to participate. Intellectual Merit: Many parameters have been considered in evaluating liquefaction, but temperature or dissolved gas have not been among them. Preliminary analysis by the P.I. suggests that, other things being equal, liquefaction may be more widespread in warmer climes. Because of this, the idea of temperature dependence is worth pursuing both from an intellectual merit to understand the process and from economic and public safety standpoints.