【摘要】 随着我国城市化进程的加速,城市的地震安全问题变得越来越重要,特别是近城镇中强地震对我国众多中小城市的威胁,玉树地震和宁洱地震即是两个典型的震例.城市地震安全问题包括城区建筑以及城市基础设施两个方面.基于地震现场调查的结果,本文给出了两个县城各类结构的破坏比及震害指数.在这两次地震中未设防的民居建筑遭到严重破坏甚至倒塌,再次表明地震活跃地区房屋建筑抗震设防的重要性.城市的基础设施包括交通、通信、供水和供电等生命线系统.交通系统方面,重点调查了玉树县城周边桥梁的震害情况,道路桥梁的破坏主要集中在Ⅷ度以上地区.供电系统方面,两次地震都造成当地小水电站、电气设备、输电网络严重破坏.光缆是通信系统中相对薄弱的环节,强地震动和滑坡等常常引起光缆中断.两个县城的供水管网在地震中都几乎瘫痪,破坏的主要原因是管道老旧和管材的抗震性能差.在城市基础设施抢修恢复过程中,供水和供电系统由于抗震能力相对较弱,恢复所需的时间较长,而交通和通信恢复速度较快.更多还原

【Abstract】 With the process of urbanization in China,the urban seismic safety becomes more and more important,especially those threat of urban earthquakes on many small cities,for example,Yushu Earthquake and Ning’er Earthquake.Urban seismic safety includes the safeties of city buildings and urban infrastructure.Based on the investigation of damage site,the damage ratios and the mean damage indexes of different type structures of two cities are obtained.Those residential buildings without seismic design were badly damaged or even collapsed in Yushu Earthquake and Ning’er Earthquake.These lessons shows again that the seismic design is very importance for the buildings in seismic-active regions.Urban infrastructure includes transportation,communication,water supply and power supply system.For the transportation system,the damage of bridge is mainly located on the region with the seismic intensity larger than Ⅷ based on the investigation of bridges around Yushu city.For the power supply system,Both of the two earthquakes have caused local small hydropower stations,electrical equipment and power transmission network severely damaged.For the communication system,the cable is more easier to be damaged by the strong ground motion and landslides.Water-supply systems were almost totally damaged in theses two earthquake,because of the poor-seismic-resistant water pipe.For the recover of urban infrastructure,water and power supply systems need more time to be repaired,and the transportation and communication systems are restored quickly.更多还原