埋设管网系统地震危险性分析方法

METHOD OF SEISMIC HAZARD ANALYSIS FOR BURIED PIPELINE NETWORK SYSTEM

埋设管网系统有如下三个特点,即:埋于地基中、在平面内延伸分布范围广、具有生命线工程的重要性,故其抗震设计与地震危险性分析方法也与一般房屋建筑不同。为此,本文提出了一种同时考虑给定地震下地震动场的空间相关性、局部场地条件及地震发生非确定性影响的地震危险性分析方法。本文建议的方法中给定地震下地震动场的确定包括四方面的工作:①确定地震动场的参数,用场内各点之间的相对运动(如相对变形)而不是单点的运动(如加速度);②在频域内确定场内单个点的地震动,以幅值谱与相位谱表示;③用若干个离散点的地震动来描述地震动场;④考虑局部场地的影响。地震动空间相关性与地震发生非确定性同时考虑之间的矛盾问题在本文方法中也得到了处理,采用这一方法的优点是在地震动场中同时考虑了震级、距离及场地的影响,本文提出的方法也可以用于在平面上分布范围较广的其它生命线网络工程。

There are three features about the buried pipeline network system, that is, buried in foundation, extented and distributed in plane in a large scale, and possessed of the importance of lifeline engineering, thus the method about it's seismic design and seismic hazard analyses are different from those for the common buildings. In view of these, for the buried pipeline network system, a systematic seismic hazard analysis method is suggested to consider the effects of spatial correlation of earthquake ground motion under given earthquake occurence, local site condition and random earthquake occurence. The determining the earthquake ground motion field under given earthquake occurence includes four parts, (1) the specificaton of the parameters describing the earthquake ground motion, the parameters should be the relative deformation among points in space for buried pipeline network system but not the peak acceleration at single point in space; (2) the determination of the earthquake ground motion at single point in space in frequancy domain, in terms of amplitude spectrum and phase spectrum; (3) the descrepton of the earthquake ground motion field by earthquake ground motions at a series of descrete points in space; and (4) the consideration of the local site effects. The contradictory problem between the consideration of the spatial correlation of earthquake ground motion field and the random earthquake occurence is solved in this method. The advantage of this method is that the effects of the earthquake magnitude, distance, site condition are simultaneously taken into account in the earthqake ground motion field. This method is also suitable for the problems of other lifeline netword system distributed in plane.