中国强地面运动研究进展

简要总结了近年来我国在强地面运动资料的处理、近断层地面运动的影响因素、强地面运动的模拟和宽频带反应谱等方面的研究工作．同时，回顾与展望了我国在强地面运动研究方面的国际合作进展．      

伊朗Sarcheshmeh铜矿爆破振动研究di

地面振动是爆破产生的副效应之一，爆破中，相当一部分能量通过其产生的地面振动而被消耗，从而导致矿山产量大降，甚至影响矿山的发展．本文处理并分析了在伊朗Kerman 省Sarcheshmeh铜矿11次爆破记录到的57个三分向地震图．这些数据通过数字化地震仪PDAS-100记录得到，并使用DADISP软件加以分析．最后，重新考察了影响地面振动的爆破参数，比如炸药的重量和种类、结构物与爆破点的距离、爆破延时等，并研究了它们对峰值质点速度（vPP）的影响．在此基础上，确定了合适的爆破延时及炸药种类．通过研究这些数据，为Sarcheshmeh铜矿作出了vPP与换算距离之间的关系图．有了这样的关系图，就能够确定结构物的安全距离及相应的炸药数量．      

中国华北峰值加速度的衰减特性及与北美东部的比较

利用唐山强余震的强地面运动记录,研究了近场强地面运动水平峰值加速度的衰减特性,得到了唐山地区的衰减关系(土层、土层与基岩)．此外,还得到了北美东部的衰减关系,并将其与中国华北的衰减进行了比较,认为两者的衰减趋势是比较一致的．中国华北的衰减特性可供北美东部参考．      

任意圆弧形凸起地形中隧洞对入射平面SH波的影响

借助辅助函数的思想， 采用波函数展开法给出了圆弧形凸起地形中隧洞对入射平面SH波影响问题的一个解析解．数值结果表明，凸起地形中隧洞的存在以及隧洞大小，对凸起地形表面运动，以及凸起地形中的隧洞的动应力集中均具有显著影响．      

节理岩体地下洞室群的地震动力响应分析

节理岩体开挖后经常形成楔形体，对大型地下洞室顶拱和边墙的稳定笥构成威胁。地震的动力作用将加剧块体的运动，进而影响洞室的整体稳定性，合理地评价高烈度地区大型地下洞室的稳定性具有现实意义。节理岩体中地下结构的动力响应与稳定性分析目前研究较少。本文采用了动力离散元法分析了大型地下洞室群的动力响应，认为地下结构并不能完全免于震害，高烈度地震对于节理岩体中的地下结构有明显影响。     

1303年洪洞8级地震GIS系统与震害分布特征分析

采用GIS技术，建立了1303年洪洞地震的地理信息系统. 应用GIS平台空间分析功能研究了1303年洪洞地震的震害空间分布特征和地震等震线的特点. 通过与标准地震烈度衰减关系的对比，分析了地震烈度异常分布的空间特征及其与构造、场地条件、盆地之间的关系. 研究了震源与近源地下结构对地表地面运动的影响，探讨了这种烈度分布特征对区域地震区划、抗震设防、震害预测以及地震应急响应等方面的影响.      

深部洞室中微小温度年度变化足以造成地应变年度变化

利用轴对称线弹性模型有限元方法,计算了洞室中温度微小年变化引起的地倾斜和地应变. 结果表明,在满足地震台站建设规范的情况下(洞室内温度年变化幅度应小于等于0.5℃）,当洞室中温度年变化幅度仅为0.2℃时,仍会引起量级为10-7 rad的地倾斜和10-7的地应变,并且在洞室的尽头和拐弯处由于热汇聚和热扩散的作用引起地倾斜和地应变的变化更为突出. 因此今后在观测中,有必要进一步减小洞室内温度年变化;在台站设计建设和仪器布设中,对基线式仪器和摆式仪器都可以做一些恰当考虑,以尽量压制温度年变化带来的影响.      

台海地区的地壳运动与变形

利用福建沿海GPS网和台湾-吕宋GPS网站速度数据和两个网数据处理中共用的IGS永久站数据，实现了两个GPS网参考框架和速度场的统一．分析台海地区的速度场发现，福建沿海、台湾海峡与台湾岛北部地壳的水平运动完全一致，运动方向约为东偏南26.0，运动速率约为39 mm/a；台湾岛东部的海岸山脉地区发生了相反变化，运动方向为北偏西30.0，运动速率约为33.3 mm/a；在台湾岛的南端存在南偏西50.0方向的运动，运动速率约为13 mm/a．若以福建沿海的几何中心为参考基准，台湾岛存在一致的(岛的北端除外)北西向运动，方向北偏西约50.0，东海岸的速率最大为61 mm/a，向西逐渐减小．应变场分析表明，台海地区存在统一的应变场，主压应变方向为北西48.0，主张应变方向为北东42.0．主压应变速率，台湾岛的东海岸为3.43610－7/a，向西逐渐减小，到福建沿海减小到1.86110－8/a．菲律宾海板块在台湾岛东部与欧亚板块的碰撞俯冲是台海地区地壳运动、变形和发生大地震的主要驱动力．本区的主压应力方向约为北西55.0．      

地震震源的研究:/

简述了1999~2002年中国学者在地震震源的观测、实验和理论方面所取得的一系列成果. 他们对精确定位、地震矩张量反演和震源参数反演等方法进行了改进和发展，并利用这些方法，研究了许多重要地震事件的破裂过程，并结合地面形变测量，研究了地震破裂与区域应力场、地质构造运动的关系. 总之, 在实验和理论研究领域中，中国学者在地震成因、地震发生的应力与构造条件、地震破裂动力学、岩石断裂力学、地震破裂成核等方面取得了一系列进展.      

利用差分干涉雷达测量技术(D-InSAR)提取同震形变场h

简要介绍了合成孔径雷达干涉测量技术、差分干涉雷达测量技术，并对干涉测量精度进行了简单讨论．以西藏玛尼地区为例，通过三通差分干涉处理，获取了玛尼地震同震形变场.结果表明:形变场长200 km、宽115 km．干涉条纹以北东东向发震断层——玛尔盖茶卡断层为中心分布，且基本与发震断层平行；通过对干涉形变图进行分析，发震断层可分为3段，其中西段长约23 km，中段长约60 km，东段长约26 km，整个发震断层共长110 km；震中附近最大隆起斜距向位移量为162.4 cm，断层西侧最大沉降斜距向位移量为103.6 cm，震中最大地面水平位错为7.96 m．      

A series solution for surface motion ampli-fication due to underground group cavities: Incident P waves

Introduction In recent years some big cities in China commonly build subways in central urban areas to improve crowded surface transportation, and the subways usually are large-scale group cavities composed by two parallel cavities. Construction of large-scale group cavities will certainly affect the design ground motion near the cavities, and further affect seismic safety of the existing build-ings nearby. So it is of significance to estimate this effect on seismic design of the buildings. H…     

A series solution for surface motion amplification due to underground twin tunnels: incident SV waves

A series solution of displacement response of the ground surface in the presence of underground twin tunnels subjectcd to excitation of incident plane SV waves is derived by using Fourier-Bessel series expansion method. The numerical parametric study shows that underground twin tunnels significantly amplify the nearby surface ground motion. It is suggested that the effect of subways on ground motion should be considered when the subways are planned and designed.     

Amplification of in-plane seismic ground motion by group cavities in layered half-space (Ⅰ)

Amplification of in-plane seismic ground motion by underground group cavities in layered half-space is studied both in frequency domain and time domain by using indirect boundary element method (IBEM), and the effect of cavity interval and spectrum of incident waves on the amplification are studied by numerical examples. It is shown that there may be large interaction between cavities, and group cavities with certain intervals may have significant amplification to seismic ground motion. The amplification of PGA (peak ground acceleration) and its PRS (peak response spectrum) can be increased up to 45.2% and 84.4%, for an example site in Tianjin, under the excitation of Taft wave and El Centro wave; and group cavities may also affect the spectra of the seismic ground motion. It is suggested that the effect of underground group cavities on design seismic ground motion should be considered.     

地下空洞的面波场地效应数值模拟研究

工程中存在大量的地下空洞结构,这些空洞会影响地震波的传播从而产生场地效应.通过数值模拟方法研究分析地下空洞对面波传播的影响和场地效应.结果表明:面波在传播中遇到地下空洞会发生散射和反射,产生反方向传播的反射面波和向空间传播的转换体波,使得空洞的远源侧中部和下方能量大幅增强,远源侧地表及近地表处能量有所减弱,近源侧能量稍...     

ANALYSIS OF AMPLIFICATION CHARACTERISTICS OF GROUND MOTIONS IN THE HEAVILY DAMAGED BELT ZONE DURING THE 1995 HYOGO-KEN NANBU EARTHQUAKE

To estimate the amplification characteristics of ground motions in the heavily damaged belt zone in Kobe City during the 1995 Hyogo-ken Nanbu earthquake, 3D wave propagation analyses of a 2D deep irregular underground structure model with a vertical discontinuity were performed at an early stage as a preliminary and qualitative study. The hyperelement method was applied to the analyses for incident plane waves expected from the wavefields due to the source mechanism. The observation records at Kobe University of the rock site were used as control motions. The ground motions on the engineering bedrock (assumed to be on the free surface of the Osaka group layers having a shear velocity of 500 m/s) and at ground surface were calculated. The effects of the deep irregular underground structure and shallow surface layers on the ground motion amplification are discussed. Although there are qualifications due to the uncertain characteristics of the input rock motion and shear wave velocities of the underground structure, the analytical results show that the ground motion in the heavily damaged belt zone were amplified due to the focusing effect of the deep irregular underground structure as well as the shallow surface layers, and that the calculated peak ground acceleration (PGA) distribution coincided closely with the distributions of structural damage. © 1997 by John Wiley & Sons, Ltd.     

Effect of underground cavities on surface earthquake ground motion under SH wave propagation

A theoretical approach is presented to study the antiplane seismic response of underground structures, subjected to the incidence of both plane and cylindrical waves. The structure is assumed to be a circular inclusion embedded in a homogenous, isotropic and linear visco‐elastic halfspace. The inclusion may consist either of a cavity, with or without a ring‐shaped boundary, or it may be filled in with a linear‐elastic material, without loss of generality. The analytical solution is obtained using expansions of wave functions in terms of Bessel and Hankel functions, relying on the technique of images and the use of Graf's addition theorem to enforce the boundary conditions. The effects of underground cavities on surface earthquake ground motion are studied as a function of the size of the cavity, its embedment depth, the frequency content of the excitation, the incidence angle and the distance from the axis of symmetry of the cavity itself. A simple application of Rayleigh's method allows us to verify that the ground surface response is dominated by the fundamental vibration mode of the portion of soil between the cavity and ground surface itself, in the frequency range of interest for engineering purposes. A simple relationship to estimate the fundamental natural frequency as a function of the embedment depth of the cavity is given. Finally, amplification factors on response spectra are obtained, to provide a practical insight into the effect of an underground cavity on surface ground motion during real earthquakes. Copyright © 2009 John Wiley & Sons, Ltd.     

Detecting underground cavities using microtremor data: physical modelling and field experiment

In this paper, we study the possibilities of the use of microtremor records in the detection and delineation of near‐surface underground cavities. Three‐dimensional physical modelling data showed that the averaging amplitude spectra of a large number of microtremor records makes it possible to evaluate the frequencies and amplitudes of compressional standing waves generated by microtremor in the space between the ground surface and underground cavities. We illustrate how these parameters can be used to estimate the shape of the underground cavity horizontal projection. If the compressional wave velocity in the enclosing rock is known, it is possible to evaluate the depth to the cavity top using the frequencies of the standing waves. The results of the field experiment confirmed the possibility of underground cavities detection using microtremor data.     

地下衬砌洞室对Rayleigh波的放大作用

本文利用波函数展开法,给出了半空间中圆形衬砌洞室引起的Rayle igh波散射问题的一个级数解,并通过对求解技术的改进,获得了高频解答。论文通过入射波长、洞室直径、衬砌刚度和埋置深度等参数分析,研究了地下洞室对Rayle igh波的放大作用。数值结果表明,地下洞室情况下地表位移幅值可以达到无洞室情况的2.6倍以上;多数情况下,柔性衬砌洞室情况地表位移幅值最大,无衬砌洞室情况次之,刚性衬砌情况最小。     

Ultrasonic modelling research of earthquake response of underground lifeline engineering

Earthquake response of underground lifeline engineering is investigated by the method of ultrasonic model experiments in this paper. From general field conditions, two models of underground lifeline engineering, one for non-uniform field and the other for uniform field, are designed based on the similarity principle. Besides analysis of seismic phases, a series of analyses especially on particle vibration are carried out. The results show that: The shorter the epicentral distance, the greater are the intensity variation and the change rate of intensity variation of earthquake ground motion, so the more disadvantageous to underground pipelines. In soft covering layer, compressional waves mainly cause radial flexures deformation, but shear wave result in axial dilation deformation of the pipelines; when the thickness of the covering layer is smaller (less than seismic wave length), the rhythmic variation of the intensity of earthquake ground motion is controlled mainly by the wave length of seismic waves in the bedrock. The property of the covering layer has considerable effect on earthquake ground motion. For different covering layers, their effect on each component of earthquake ground motion is not the same. Owing to the effect of wave propagation, the ground is in different states of particle vibration at different times, and there is considerable difference in phase and intensity of particle vibration between two different covering layers near their junction line or surface. Because underground lifelines tend to vibrate with the particles of the earth around it, this results in different deformation of underground pipelines under different conditions. So, it is necessary to take corresponding anti-seismic countermeasures for pipelines according to their practical situations. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,14, 104–110, 1992. This paper is part of the research supported by Funds of Doctoral Faculty of National Education Committee.     

基于强震动记录确定的场地卓越周期

本文介绍了3种根据场地强震动记录获取场地卓越周期的方法: ① 地表记录的傅里叶谱分析法; ② 地表水平/垂直傅里叶谱比法; ③ 地表/地下傅里叶谱比法. 基于日本强震动观测台网KiK-net中两个基岩台站和两个Ⅲ类场地台站获取的数百条强震动记录, 分别使用上述3种方法确定场地的卓越周期, 并对比分析各种方法的优缺点及其适用情况. 结果表明: 对于基岩场地, 由于记录信息复杂, 局部场地条件对地震动影响较小, 地震动自身特性突出, 导致3种方法所得到的结果均比较分散; 对于土层场地, 场地条件影响比较显著, 3种方法基本都可以得到一个较为准确的数值; 但对于某些场地, 地表水平/垂直傅里叶谱比法所得结果存在不确定性, 相比之下, 地表/地下傅里叶谱比法则能给出一个更为准确的场地卓越周期值.