摘要
我国是世界上大陆地震发生最多的国家之一,20世纪全球2次死亡人数大于20万的地震都发生在中国。震害的发生受到场地条件和基岩条件的共同影响,而迄今为此,对场地影响的考虑相对比较成熟,对基岩的影响则相对考虑较少。大陆地震的发生是由活断层的活动而致,而地下岩体快速破裂错动传播是导致地震的直接原因,通过地下基岩能量、位移和破裂概率等指标的数值计算,可以进一步分析其对地震动的影响。基于基岩破裂指标的分布,应用人工神经网络方法,确定了基岩破裂指标与地震影响系数之间的关系,得到了地震影响系数计算模型,进而计算得到唐山市地震影响系数分布。根据计算结果,对城市规划和工程建设提出了几点建议。
China is the country with land earthquake taking place frequently. All the two big earthquakes during 20 century in the world,which caused more than 200 000 lives lost,took place in China. Land earthquake is mainly caused by fault activity and quick transmission of earthquake waves in land. Earthquake disaster is controlled by two main factors,site condition and base rock condition. The consideration of site condition is usually made in earthquake disaster prediction,but less attention is paid to base rock condition. As densely populated area with highly developed civilization,city shows obvious fragility to natural disasters. Tangshan,as a heavy industry city with six million populations,is located in the north east of Heibei province,China,and has been frequently suffered from natural disasters such as earthquake,karst collapse and ground collapse. The Big Earthquake in 1976 of Tangshan still remained freshly in peoples memory,which caused 240 000 lives lost,and especial attention has been paid to disaster resistance. Earthquake affecting coefficient is one of the most important factors for earthquake security evaluation,but it is very difficult to determine earthquake affecting coefficient accurately because of the influence of underground rock conditions. Traditional methods couldn抰 analyse well earthquake resistance in city and engineering construction. Based on numerical calculating results of energy,and cracking probality in undeground base rock,the influences of these factors on earthquake affecting conefficient are analyzed. According to the base rock condition parameters,neural network method is applied,and the relation among earthquake affecting coefficient,energy,displacement and cracking probablity of undergroud rock is determined. The calculating model of earthquake affecting coefficient is constructed and the distribution of earthquake affecting coefficient in Tangshan city is calculated. From the calculating results,it is found that the earthquake affecting conefficient in southeast of Tangshan city is bigger than 0.48,even more than 0.64 somewhere,which means that the intensity of earthquake disaster is 10 degree. At last,some suggestions for city planning and engineering construction are given.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2004年第10期1765-1769,共5页
Chinese Journal of Rock Mechanics and Engineering
基金
国家计委重点科技项目(攻关)计划(98-01-02)
河北省科学技术研究项目(03276901)资助项目。
关键词
唐山市
基岩
破裂
数值模拟
神经网络
地震影响系数
earthquake,cracking,earthquake affecting coefficient,base rock,numerical simulation,neural network,Tangshan city
