珠江三角洲土坝和堤围震害初步预测

本项预测采用概率方法,即首先根据广东省水利部门提出的55座土坝和59个重点的座标(见附图),进行概率地震危险性分析,给出它们在一定预测年限T(取50年和100年)的地震烈度Ⅰ的超越概率;其次根据近年我国发生的几次强震时处于不同烈度区内的土坝和堤防的震害资料,形成表示土坝和土堤地震易损性的震害概率矩阵;然后,根据上述两方面结果用概率公式评价各土坝和堤围点在预测年限内各震害等级的超越概率,并取10％超越概率为标准,估计震害等级。结果表明,珠江三角洲土工构筑物的地震危害性南部高于北部。

Preliminary Prediction of Earthquake Hazard of Earth Dams and Embankments in Pearl River Delta

In the prediction, probabilistic methods are used. Based on the coordinate of 55 earth dams and 59 major embankments proposed by water conservancy departments in Guangdong, the first step is to carry out probability analysis of earthquake hazard to set their probability transcending earthquake intensity I in a certain period of time T (50 years and 100 years are adopted). Then, according to the earthquake hazard data of earth dams and embankments located in regions with various intensity during strong earthquakes occurring in recent years, the next step is to form a hazard probability matrix representing the seismic vulnerability of earth dams and embankments. Finally. based on the results obtained from the above two steps, transcending probability of various hazard grades for dams and embankments in prediction period can be evaluated by using probability formulas. Taking transcending probability 10% as standard, hazard grades can be estimated. The results show that vulnerability of earth structures in the Pearl River Delta is higher in south than in north.