形变台点异常事件与强震活动关系的研究

收集了我国大部分跨断层流动测量和跨断层形变台站资料,统计了阶跃、突跳、趋势转折和年变规律改变等异常变化,并与相应区域内Ms≥6．0以上地震的时空分布进行了对比分析,结果认为：(1)突出的台点形变异常和强震活动在上一个强震活动高潮期均存在由西南向华北往复迁移的特征;(2)突出的台点形变异常峰值期与强震活动高潮期存在一定的对应关系;(3)1987年以来形变异常和强震活动由西南向华北迁移的特征不明显,但地震活动在南北带上往复迁移的特征仍然存在;(4)未来一段时间内,华北发生Ms6．0以上强震的可能性不大,而南北带的北部不能排除。     

常德至张家界高速公路慈利段典型岩质边坡成生机理初探

在山区修建高速公路时,由于“高填深切”改变了自然条件下的地质营力,从而带来一系列的环境地质问题,尤以岩质边坡开花后的稳定问题突出,只有对自然岩质边坡进行深入的研究,才能更好地提出合理的人工边坡设计方案．而传统的岩质边坡分析方法多是定性的笼统地分析,对岩质边坡的成生机理难以做到具体的分析,许多地质现象无法解释．运用系统工程地质有关边坡变形渗流场的稳态坡形理论对常德至张家界高速公路慈利段的典型岩质边坡的成生机理及边坡开挖后的破坏机理进行了分析,为人工边坡的设计提供了可靠的依据．     

基于损伤模型的圆形洞室矿震分析

采用应变损伤模型对圆形洞室矿震的发生进行了解析分析,得到了发生矿震的洞室临界塑性区深度和临界作用力,得出损伤内变量k0,kc是决定圆形洞室矿震发生的重要参数.     

Geodetic measurement of the local elastic response to the changing mass of water in Lago Laja, Chile

A geodetic station (ANTC) built in bedrock in southern Chile is undergoing non-steady vertical motion within a range of nearly 50 mm. These fluctuations are dominated by the earth’s local elastic response to the changing weight of water in a reservoir located about 20 km away. There is also an annual periodic component of motion that is attributed to global and regional patterns of loading, as well as a steady tectonic signal. The local loading response constrains the average elastic structure of the area, and implies a stiffness that falls near the lower end of the range observed in rock samples.     

Non‐linear seismic response of the rail‐counterweight system in elevators in buildings

Elevators in buildings serve a very important function and are among the critical components of an essential facility. They have several mechanical and electrical components that are known to be susceptible to damage during earthquake occurrences. The counterweights, being the heaviest, are among their most vulnerable components. The ASME code has made several provisions to improve the performance of the counterweights in seismic events. To evaluate their performance under code‐mandated provisions, it is necessary that a comprehensive and realistic analytical model is used. This paper uses a detailed model of a counterweight of a traction elevator to study its in‐plane and out‐of‐plane dynamic behavior. The model incorporates the multiple support inputs and flexibilities of the counterweight guidance system along with their non‐linearities caused by the clearance limitations. The study examines the effect of changing clearances, variability of input motions, and the use of tie brackets on the system response, and evaluates the impact of some of the code provisions on the dynamic behavior of the system. Copyright © 2003 John Wiley & Sons, Ltd.     

Evaluation of site‐dependent constant‐damage design spectra for reinforced concrete structures

An investigation on the validity of the conventional design approach known as constant displacement ductility is carried out. The hysteretic behaviour described by the Modified Takeda model is taken to represent the characteristics of reinforced concrete structural systems. The results presented in the form of seismic damage spectra indicate that the conventional design approach may not be valid because cumulative damage is excessively high. The inelastic design spectra based on the constant‐damage concept are proposed in terms of simplified expressions. The expressions are derived from constant‐damage design spectra computed by non‐linear response analysis for SDOF systems subjected to ground motions recorded on rock sites, alluvium deposits, and soft‐soil sites. The proposed expressions, which are dependent on the local soil conditions, are functions of target seismic damage, displacement ductility ratio and period of vibration. The seismic damage of structures that have been designed based on this new design approach is also checked by a design‐and‐evaluation approach. The results are found to be satisfactory. Copyright © 2004 John Wiley & Sons, Ltd.     

Automatic recognition of damaged town buildings caused by earthquake using remote sensing information: Taking the 2001 Bhuj, India, earthquake and the 1976 Tangshan, China, earthquake as examples

Introduction As we well know, the hazard of earthquake is very wide especially in cities. The conventionalmethods to investigate the damage are difficult to meet the requirements in applications. In recentyears, with the rapid development of remote sensing, especially the successful launch and applica-tion of high-resolution commercial remote sensing satellite, it has become possible to recognize andextract damage information by using remote sensing. The researchers at home and abroad hav…     

The GIS and analysis of earthquake damage distribution of the 1303 Hongtong M=8 earthquake

Introduction The 1303 Hongtong earthquake is an important earthquake in the eastern China. There is a lot of information in historical documents about the earthquake and many traces destroyed by the earthquake in the southern Shanxi Province. Many scholars have studied the earthquake from dif-ferent aspects, but mainly limited the definitions of the isoseismal and three factors of the earth-quake. Owing to being limited by the analysis technique, many useful damage information of the earthqu…     

哀牢山造山带南段构造混杂岩-蛇绿岩带的发现

三台坡岩组为哀牢山断裂南段新发现的一套构造混杂岩。在剖面大理岩化灰岩中采获牙形石，经鉴定时代为早石炭世。该套岩石为位于扬子准地台与唐古拉．昌都．兰坪．思茅褶皱系两个一级大地构造单元间的哀牢山断裂带上的构造混杂岩，至少经历4期变形变质。据原岩恢复和变质残余组构，具蛇绿岩套组合特征，断裂带应为板块俯冲带(缝合线)。三台坡组的发现，为研究哀牢山造山带南段地质发展演化提供了依据，填补哀牢山断裂带南段构造演化研究空白。