华北近十年来水平运动动态与地震活动危险区的讨论     

周晓燕  杨国华  韩月萍 《华北地震科学》2002,20(4):28-33

根据华北地区1999年和2001年两期高精度GPS观测结果，通过与1992，1995，1996年和1999年这几期资料的比较，发现近两年的运动与前有所不同，主要表现为：（1）阴山单元和鄂尔多斯单元之间显示为压性运动的性质，但比较微弱，它们之间的边界带上似乎有左旋走滑运动，但从整体上看并不显著。（2）晋冀鲁单元和燕山单元的整体活动性不如以前，各单元内部存在着较明显的差异运动，并山单元和晋冀鲁单元的北部存在着比较显著的东西向挤压，北京地区则表现为南北向挤压。（3）晋冀鲁单元南部与胶辽鲁苏单元的南部的趋势活动呈张性，优势运动方向为东南，这样的结果可能表明，华北目前存在着应力扰动行为，大同与天津之间的区域是受其影响最大的地区，该区有可能成为未来几年中强地震活动的一个主体地区。  相似文献   

Spatial variation of seismic motion induced by propagation of body waves     

D. Zendagui  M. K. Berrah 《Soil Dynamics and Earthquake Engineering》2002,22(9-12):805-811

Spatial variation of earthquake ground motion is an important phenomenon that cannot be ignored in the design and safety of strategic structures. Several models have been developed to describe this variation using statistical, mathematical or physical approaches. The latter approach is not specific to an event. A recent contribution, which uses such an approach and called complete stochastic deamplification approach (CSDA), was developed [1]. The aim of this paper is to analyze the spatial variation of earthquake motion induced by the propagation of body waves using the CSDA. Coherency functions are evaluated for the cases of SH–SV–P waves propagating through stratified soil. Results obtained show that the variation of the coherency function is not the same for vertical and horizontal components and that the motion is more coherent at depth than at the free surface. In fact, we found that the rate of decrease with frequency and distance is not the same if P–SV waves propagate through stratified soil.  相似文献   

桥梁限位器抗震设计方法研究   总被引：4，自引：0，他引：4  

戴福洪  翟桐 《地震工程与工程振动》2002,22(2):73-79

本文建立了两跨简支梁桥和五跨多跨刚架桥两结构模型，针对限位器的种类、刚度、强度、安装位置，输入地震动等进行了大量工况下的数值模拟研究。研究表明限位器与柱（框架）的刚度比在0.5-2之间较优。将现有的限位器设计方法应用于两算例结构，对现有限位器设计方法进行了比较研究。  相似文献   

依据剖面资料求解断层的水平位移     

安晓文  李世成  周瑞琦  俞维贤  陈宇军 《地震研究》2002,25(4):369-373

提出依据开挖剖面中的楔形体在受到断层作用时其厚度的变化量求解断层水平位移的方法。分析表明断层水平位移量S与楔形体在断层两侧厚度变化量Δh满足关系式S＝Δh/ρsinβ。式中ρ为楔形体在断层走向上的尖灭系数，β为断层的倾角，该关系式不仅能满足纯走滑运动的断层，而且也满足一般斜滑断层，同时提出了在剖面上判断断层水平运动性质的方法。  相似文献   

Recent developments in seismically isolated buildings in Japan     

Shin Okamoto  Nagahide Kani  Masahiko Higashino  Norihide Koshika  Masayuki Kimizuka  Mitsumasa Midorikawa  Masanori Iiba 《地震工程与工程振动(英文版)》2002,1(2):213-225

The Building Standard Law of Japan and related Enforcement Order and Notifications have been substantially revised since the year 2000 to introduce a performance-based regulatory and deregulation system for building control systems. Up to then, time-history analyses were mandatory for isolated buildings and had to be specially approved by the Minster of the Ministry of Construction (MOC). Simplified design procedures based on the equivalent linear method for seismically isolated buildings have been issued as “Notification 2009 — Structural calculation procedure for buildings with seismic isolation” from MOC, and are now integrated into the Ministry of Land, Infrastructure, and Transportation (MLIT). Along with Notification 2009, “Notification 1446 of year 2000 — Standard for specifications and test methods for seismic isolation devices” was also issued. Buildings with heights equal to or less than 60m and that are designed according to these Notifications, including base isolated buildings, only need approval from local building officials, and no longer require the special approval of the Minister of MLIT. This paper summarizes: 1) some statistics related to buildings with seismic isolation completed up to the end of 2001; 2) simplified design procedures required by Notification 2009 of year 2000; and 3) performance of seismic isolation devices required by Notification 1446 of year 2000.  相似文献   

位移监测在滑坡时空运动研究中的应用   总被引：5，自引：0，他引：5  

靳晓光  王兰生  李晓红 《山地学报》2002,20(5):632-635

滑坡时空运动特征是滑坡地质体在内因和外因共同作用下，自一种状态向另一种状态转化的地质过程。滑坡位移监测是研究滑坡变形影响因素、动态规律及预测预报的主要途径，特别是滑坡深部位移监测，又为研究滑坡体的时空运动过程提供了重要信息。本文结合几个滑坡的深部位移监测实践，综合分析位移监测信息，研究滑坡体的时空运动特征及发展趋势，为滑坡时空运动系统研究及稳定性预测提供依据。  相似文献   

Geographies of Displacement: The Karenni and The Shan Across The Myanmar-Thailand Border   总被引：1，自引：0，他引：1  

Carl Grundy-Warr  & Elaine Wong Siew Yin 《Singapore journal of tropical geography》2002,23(1):93-122

First, central to our analysis is the argument that human movement within and across borders fundamentally challenges the view of geopolitics based upon fixed territorial states, inter-state relations, national identities and citizenship; indeed the whole idea of "national geographic". Using the examples of the Karen and Shan peoples, we explore the processes and patterns of forced relocation, displacement and migration in the border regions of Myanmar and Thailand. Our main concern is with forced displacement as a result of political and ethnic conflict; specifically, how the Burmese military regime's desire for "national unity" within Myanmar's "national space" has influenced the militarily inspired displacements of hundreds of thousands of villagers and civilians within the border zones inhabited mostly by so-called "national minorities". We examine the particular problems of the so-called "internally displaced persons" within "national" boundaries compared with the "refugees" and "undocumented migrants" who make it across "international" space into Thailand. We illustrate the ways displaced people are represented by state agencies and the media as "threats" and "transgressors". We consider some of the "long term" aspects of the displacement problem along the Myanmar-Thai border and the vital contribution geographers can make to the study of displacement.  相似文献   

挠曲线复位的微分方程解法求梁的位移   总被引：5，自引：0，他引：5  

喻晓今 《华东地质学院学报》2003,26(3):271-273

梁位移求解的方法主要有两种：积分法和叠加法。积分法的困难是当多个荷载同时作用时，要按控制面分段列弯矩方程，这样，两次积分时带来的积分常数较多，导致依边界条件、连续条件定这些常数时要解多个联立方程，计算繁杂。梁位移求解的叠加法是借用典型荷载下梁已知积分结果来进行对应位置位移的叠加，具体是查转角方程、挠曲线方程表格。从表中知，梁任一位置处的位移方程大多是多次多项式，很难记忆，故离开表格便无法采用。本文找到了一种新的方法求梁的位移，通过设置比拟梁，使比拟梁的挠曲线复位于原梁，从而建立了相应的微分方程，求解此方程后便可得梁的位移，避开了分段多次积分或查表的弱点。  相似文献   

郯庐断裂带的平移运动与成因   总被引：61，自引：4，他引：61  

朱光刘国生  牛漫兰宋传中 王道轩 《地质通报》2003,22(3):200-207

在华北、华南板块碰撞期间，郯庐断裂带究竟是何种边界仍是没有解决的重大地学问题，许多学者对此提出了不同的构造解释模式。关于郯庐断裂的平移距离仍存在着较大的分歧与有待深入研究之处。在华北、华南板块拼合之后，郯庐断裂带发生了一次大规模的左行平移，其糜棱岩的^40Ar／^39Ar年龄为132～119Ma，指示为早白垩世的平移活动，平移活动中伴生了强烈的岩浆活动。这期左行平移标志着中国东部构造的重大转折，是滨太平洋构造对前期古特提斯构造的叠加，其动力学机制为太平洋区伊侨奈岐板块突然出现的高速斜向俯冲。  相似文献   

扁铲侧胀试验判别液化的研究和实践   总被引：8，自引：0，他引：8  

陈国民  李隽毅  汤智青 《上海国土资源》2003,(1):20-24

通过对扁铲侧胀试验判别液化的研究和实践，提出了在上海地区采用扁铲侧胀试验判别液化的公式，扁铲侧胀试验判别液化与标准贯入和静力触探试验判别液化的方法对比，具有相对较好的结果，是一种有前途的液化判别方法。  相似文献