场地液化特征研究及液化影响因素评价

发布时间：2018-03-29 01:07

本文选题：液化　切入点：相关性　出处：《中国地震局工程力学研究所》2013年博士论文

【摘要】：震害调查是获取工程震害资料和经验最重要的手段,也是工程抗震理论和分析方法发展的基础。工程地震学的发展离不开历次地震考察,特别是破坏性地震震害启示。我国抗震设计技术演化历程中,河源(1962)、邢台(1966)、通海(1970)、海城(1975)、唐山(1976)和汶川(2008)等大地震深入的震害调查和现场勘测,对我国工程抗震技术的发展及抗震规范的形成起到了极大的推动作用。地震液化及震害在以往历次大地震破坏中占有相当的比重,是岩土地震工程学者及工程师密切关注的课题。目前液化研究已经取得了很大进展,但从现有的成果看,离客观需求还有很大距离,特别是以实际液化调查数据分析场地液化特征以及从实际资料出发研究影响液化的因素等方面,近些年成果尚少,一定程度阻滞了岩土地震工程和土动力学的发展,主要表现在：(1)缺乏地震现场液化宏观评价的调查方法和描述标准,使得研究人员对地震中液化程度以及所造成的震害情况不能得到全面的认识；(2)国内外历次大地震中液化资料及数据缺乏系统的整理,液化数据库建设亟待解决；(3)近期国际上大地震液化实测数据分析整理不够,对实测资料中所反映液化场地特征认识不足,对国内外液化数据的差别和联系还缺乏了解,使得我国液化判别方法现状和发展方向认识不清；(4)近期大地震获取了很多宝贵的液化场地实测新数据,可以用来分析影响液化的场地特征量与液化的相关性,得到实际动荷情况、真实埋藏条件以及现场实测土力学指标与液化相关程度的真实认识,用于检验现有的液化判别方法,但以往这方面的研究成果尚少。本论文的完成的主要工作及成果如下： 1.收集整理了国内外48次大地震的液化资料,建立了场地液化资料数据库,分析了包括土层埋藏条件(埋深、水位)、土性(密实度、粒径)和基本力学指标(标贯击数)等场地特征,剖析了大陆与其他地区场地特征的差别和联系,对土层液化得到了较为全面和客观的认识,修正了传统认识上的一些错误和偏差。 2.鉴于震害调查工作的需求和现有规范的缺欠,通过对汶川地震实际液化考察过程中遇到问题及思考,提出了宏观液化指数和宏观液化等级的概念及划分标准,并对比国内外震害资料论证了所提出标准的可行性,为震后液化调查和震害评估提供一套便于参考的指标,也为液化研究积累可靠全面的基础资料提供了必要的手段。 3.系统地整理了我国汶川Ms8.0级大地震液化震害调查资料,根据获取的汶川地震液化调查资料及现场勘探数据,采用提出的宏观液化指数和等级的划分标准,深入地剖析了汶川地震液化震害,给出了汶川地震及成都、德阳和绵阳三个主要液化区的宏观液化等级分布及震害案例分析,同时利用震害调查资料,分析了液化与非液化场地震害、宏观液化指数与地震动等之间的关系,为全面、深入了解和掌握汶川地震液化特点提供了依据。 4.收集了51个国内外地震的5103例数据,利用皮氏积距相关系数法分析了PGA、水位、埋深、标贯以及波速等几个影响液化的特征参数与液化的相关性,对比分析了在不同埋深、水位和烈度范围内各参数相关性及各参数间相互关系,得到了实际动荷情况、真实埋藏条件以及现场实测土力学指标与液化关联性的真实结果,给出了大陆、台湾、欧美和日本地震中影响液化的特征参数与液化相关性的对比结果,为深化土层与地震动特征量与液化关系的认识、检验现有液化判别方法提供了支持。 5.利用建立的液化数据库,采用液化数据实际相关性与公式推演数据相关性对比方法,对我国规范中SPT、CPT和Vs液化判别公式进行了检验,给出了三个液化判别方法的可靠性评价,指出我国规范CPT液化判别公式中砂层埋深符号定性的错误以及我国规范Vs液化判别公式中砂层埋深对液化判别贡献过小的问题。 6.收集整理了2011年2月22日新西兰Christchurch地震中液化数据,分析了液化场地的特征,并利用相关性理论研究了砂层埋深和水位、标准贯入击数和地震强度等特征参数与液化的相关性,得到新西兰地震液化较为全面和客观的认识,同时分析了新西兰地震与国内外其它地震场地特征与液化相关性的差异和联系。
[Abstract]:Earthquake damage investigation is the most important means of obtaining engineering seismic data and experience , and it is also the basis for the development of seismic theory and analysis method of engineering . The development of engineering seismology is inseparable from previous seismic exploration , especially destructive earthquake damage . In the course of seismic design technology evolution in China , there are deep seismic hazard investigation and site survey of Heyuan ( 1962 ) , Xingtai ( 1966 ) , Tonghai ( 1970 ) , Haicheng ( 1975 ) , Tangshan ( 1976 ) and Wenchuan ( 2008 ) .

Seismic liquefaction and earthquake damage have a significant proportion in previous major earthquake damage , which is a subject of close attention by scholars and engineers of geotechnical seismic engineering . However , the present research has made great progress , but from the existing results , there is still a great distance from objective demand , especially in the analysis of liquefaction characteristics of the site and factors affecting liquefaction from the actual data .
( 2 ) At home and abroad , the liquefaction data and data lack systematic arrangement , and the construction of liquefaction database needs to be solved urgently ;
( 3 ) In recent years , the data analysis of liquefaction test data in the world is not enough , the lack of understanding of the characteristics of liquefaction sites reflected in the measured data , and the lack of understanding of the differences and connections between the domestic and foreign liquefaction data , so that the present situation and the development direction of the liquefaction discrimination method in China are not clear ;
( 4 ) In recent large earthquakes , many valuable new data of liquefaction site have been acquired , which can be used to analyze the correlation between the site feature quantity and liquefaction of liquefaction , to obtain the actual dynamic load , the true burial condition and the real understanding of the soil mechanics index and liquefaction - related degree in the field , which can be used to test the existing liquefaction discrimination method , but the previous research results in this area are still few .

The main work and achievements of the thesis are as follows :

1 . The liquefaction data of 48 major earthquakes at home and abroad were collected , and a database of site liquefaction data was established . The characteristics of site characteristics such as buried depth , water level , soil ( density , particle size ) and basic mechanical index ( SPT ) were analyzed .

2 . In view of the needs of earthquake damage investigation and the lack of existing specifications , the concept and division standard of macro - liquefaction index and macro - liquefaction level are put forward through the investigation of the actual liquefaction of Wenchuan earthquake , and the feasibility of the proposed standard is demonstrated by comparing the seismic hazard data at home and abroad .

3 . The investigation data of earthquake damage of Wenchuan Ms8.0 earthquake in China is systematically collated . According to the obtained data of seismic liquefaction investigation and site exploration data of Wenchuan earthquake , the macroscopic liquefaction level distribution and earthquake damage case analysis of Wenchuan earthquake and three main liquefaction areas in Chengdu , Deyang and Mianyang are analyzed . Meanwhile , the relations between liquefaction and non - liquefaction site earthquake damage , macroscopic liquefaction index and ground motion are analyzed , which provides a basis for comprehensive and in - depth understanding and mastery of the seismic liquefaction characteristics of Wenchuan earthquake .

4 . We collected 5103 data from 51 domestic and foreign earthquakes , analyzed the correlation between the parameters of PGA , water level , burial depth , standard penetration and wave velocity , and analyzed the correlation between parameters and liquefaction in different depth , water level , burial depth , standard penetration and wave velocity .

5 . By using the established liquefaction database , using the correlation of the actual correlation of liquefaction data and the formula deduction data correlation method , the paper presents the test of SPT , CPT and Vs liquefaction discrimination formulas in our country codes , and gives the reliability evaluation of the three liquefaction discrimination methods , and points out the error of the qualitative error of the sand layer buried deep symbol in the standard CPT liquefaction discrimination formula and the problem that the burial depth of the sand layer in the standard Vs liquefaction discrimination formula contributes too little to the liquefaction discrimination .

6 . The liquefaction data in Christchurch earthquake of New Zealand on Feb . 22 , 2011 is collected , the characteristics of liquefaction site are analyzed , and the correlation between the characteristics parameters and liquefaction of sand layer depth and water level , standard penetration strike number and seismic intensity are studied by using correlation theory .

【学位授予单位】：中国地震局工程力学研究所
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU435

【参考文献】