报告题目：Liquefaction Potential of Soils – a Fully Probabilistic Approach
《完全概率框架评估土壤液化潜能》
报告人：李坤博士
时间：2013年11月4日（周一）上午10:00-11:30
地点：安中大楼A322会议室
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摘要：
Soil liquefaction induced by an earthquake may be a major cause of damage to structures and facilities. Thus, evaluation of the liquefaction potential of a soil subjected to a given seismic loading is an important first step towards mitigating liquefaction-inducted damage. A new framework tointegrate the conditional probability of liquefaction with the variation of earthquake sources and the underlying model uncertainty, as reflected in the U.S. Geological Survey Seismic Hazard Maps, for a fully probabilistic analysis of soil liquefaction in a given time exposure is developed.
The improvement to the existing methods for assessing liquefaction potential is a contribution to the field of civil engineering. In recent years, performance-based design concepts in earthquake engineering have been receiving wider acceptance. One important aspect of performance-based design in the context of geotechnical earthquake engineering is estimating of the probability of liquefaction. Previous studies focused in the conditional probability of liquefaction for a given pair of acceleration and moment magnitude. The integration of the conditional probability of liquefaction with the variation of earthquake sources and the underlying model uncertainty is innovative and has practical implication. The fully probabilistic methodology is promising for engineering design. Applying this methodology in some earthquake-prone areas for mapping liquefaction potential in terms of annual probability of liquefaction should be pursued.
土壤液化往往是地震中造成房屋建筑结构和重要基础设施损坏的一个主要原因。评估土壤的液化潜能是进行工程抗震设计，减轻地震灾害重要的第一步。这个新的框架整合了的传统简化液化分析方法，以及由美国地质调查局绘制发布的国家地震灾害图提供地面峰值加速度和矩震级的组合作为地震参数，运用完全概率分析土壤液化潜能。
这个新框架对土木工程领域的贡献在于改善现有的液化潜能评估方法。近年来，在地震工程中基于性能的抗震设计理念已得到更广泛的接受。在岩土地震工程中，基于性能的抗震设计的一个重要方面就是分析估算土壤液化的概率。以往的研究主要集中在对给定的加速度和矩震级组合下，土壤液化的条件概率估算仅考虑了一个给定的单一的风险水平，而在基于性能的地震工程设计中，往往需要确定在给定地点的所有可能的地面运动下土壤液化的完全概率。这个新框架提出了一种方法，整合了地面峰值加速度以及地震的矩震级的联合分布和传统的土壤液化的条件概率分析。这个新框架采用完全概率分析计算土壤液化潜能，是很有前途的工程设计。在地震多发地区，应用此方法结合地震灾害图提供的震源荷载，分析计算土壤液化潜能，可以方便地绘制区域土壤液化风险地图。
Dr. Li serves as a Senior Project Geotechnical Engineer withGolder Associates, a premier global group of consulting companies, specializing in ground engineering and environmental science, founded in 1960 and now employing nearly 8,000 people, operating across 6 continents. He has more than 13 years of experience performing professional engineering services on a variety of civil, transportation, geotechnical, geo-environmental, and construction projects involving, but not limited to: subsurface investigation; hydrologic and hydrogeologic analyses;geotechnical earthquake engineering and liquefaction analysis; finite element analysis; foundations; soil/rock slopes; retaining structures; excavation support systems; preloading; in-situ soil stabilization; instrumentation monitoring; geophysical investigations; rock stabilization; pile installation; slurry walls; tunnels; bridge embankments; forensic investigations; and construction monitoring. He is a registered professional engineer in the State of New Jersey, USA.Dr. Li is a member of ASCE, Geo-institute, ASFE, ISSMFE, Chi-Epsilon, and DFI.
Dr. Li received his BS and MS degrees in Civil Engineering from Zhejiang University, and his Ph.D. in Civil Engineering from Clemson University in USA. He participated in research projects sponsored by NSF and USGS. Experiences include development of simplified procedures to evaluate liquefaction hazard and ground failure potential using CPT and SPT data, mapping liquefaction hazard. The focus of his research is aimed at improving existing methods for evaluating liquefaction of soils using probabilistic approach. A new framework that integrates the conditional probability of liquefaction with the variation of earthquake sources and the underlying model uncertainty, as reflected in the USGS Seismic Hazard Maps, for a fully probabilistic analysis of soil liquefaction in a given time exposure is developed.
李坤博士在高达集团任职高级项目岩土工程师。高达是全球首屈一指的工程咨询公司，专门从事地下工程和环境科学，拥有53年的历史和将近8000员工，业务遍布6大洲。李博士拥有超过13年专业工程经验,包括各种民用，交通，岩土，地质环境，建筑工程，从事地下调查，水文及水文地质分析，地震工程和液化分析，有限元分析，地基基础设计，土壤/岩石边坡分析，挡土结构设计，基坑支护系统，堆载预压，原位土体稳定化，工程监测，围岩稳定，桩安装，隧道，桥梁设计，法庭调查。他是美国新泽西州的注册专业工程师，也是ASCE，Geo-institute，ASFE，ISSMFE，Chi-Epsilon，DFI的会员。
求学过程中，他获得了浙江大学土木工程的学士和硕士学位，美国克莱姆森大学土木工程的博士学位。他参加了由美国国家科学基金会和美国地质调查局赞助的研究项目。经验包括开发简化方法，使用CPT和SPT数据以评估液化危害和地面破坏的潜力，绘制液化风险地图等。他的研究重点是为了改善现有的概率评估土壤液化方法。这个新框架整合了土壤液化的条件概率以及由美国地质调查局绘制发布的国家地震灾害图所反映的震源和模型的不确定性，采用新的完全概率框架分析土壤液化潜能。