【作者】 陈荣淋；

【导师】 曾志兴； 林建华；

【作者基本信息】 华侨大学 ， 工程力学， 2006， 硕士

【摘要】 我国是世界上地震多发国家之一，全国有60％左右的地区处于高烈度区，而砂土液化是引起地震灾害的主要原因，因此砂土液化是地震工程中的重要问题。砂土液化的发生、发展是一个复杂的过程，其影响因素很多，随机性大，且各因素之间呈高度的非线性。砂土液化势评价是抗震防灾工作的重要环节，也是岩土工程勘察中的一项重要内容，所以客观、准确地评价砂土液化势，是对有可能发生液化的区域或地段进行有针对性的预防处理的前提，是关系到工程建筑的安全使用和工程建设的经济效益的重要问题。 本文在评析传统方法的基础上，将可拓学和支持向量机理论引入到砂土液化势评价工作中，为砂土液化势评价找到了新的途径。首先，阐述了基于可拓学的综合评价理论和实现方法，并在此基础上利用网络编程技术开发了基于Web平台的可拓综合评价系统，将其应用于砂土液化势的评价研究。在详细分析影响砂土液化因素的基础上，选取了震级M、地面最大加速度g_max、标准贯入击数N_63.5、比贯入阻力P_s、相对密实度D_r、平均粒径D₅₀、地下水位d_w等7个参数作为评价指标，建立了砂土液化势的可拓评价模型，并对历史数据进行仿真评价，取得了较好的应用效果；在对支持向量机的理论进行介绍后，本文建立了基于支持向量机的砂土液化势评价模型，并利用在基于支持向量机理论的Libsvm软件，对若干国内外场地的现场实测数据进行了评价，评价结果与现场表现基本上一致。研究表明，可拓评价方法和支持向量机对于砂土液化势进行评价是行之有效的。更多还原

【Abstract】 China is among the countries where earthquakes take place most frequently in the world. 60 percent of the areas have high earthquake intensity, and sand liquefaction is the main reason that causes seismic disasters, so that the sand liquefaction is an important problem in earthquake engineering. Sand liquefaction comes through a complicate process, and it involves a great deal of influence factors, which have strong radomness and reciprocal nonlinearity. Assessment of sand liquefaction potential is the important link in the works of antiknock and disater-prevention, and is an important content in reconnaissance of geotechnical engineering, so evaluating sand liquefaction objuectively and exactly is the precondition of taking preventive measures on areas where liquefaction easily occurs. It also relates closely to the safety and economic benefits of the projects.The paper analyses and assesses traditional methods, and brings forward the theory ofextenics and support vector machine to the assessment of sand liquefaction potential, so as to find out a new path in the field of assessment of sand liquefaction potential.This paper has illustrated the essential theory of assessment method based on the extenics and realization technique of the method. According to that, a web assessment system based on the extenics theory has been developed with the web program technique, and this system was applied to the assessmento of sand liquefaction potential. Through detailed analyzing some influencing factiors of sand liquefaction, seven parameters were selected as assessment indexes. They are earthquake magnitude, peak ground surface acceleration, standard penetration value, specific penetration resistance, relative compaction, average particle diameter, and water table. The extension assessment model has been established that was applied to assessment of sand liquefaction potential. The model had been trained by the historical data and has been assessed in virtue of sand liquefaction from the historical data by simulating, and got a excellent result. After introduction of the support vector machine theory, this paper established the assessment model of sand liquefaction based on the support vector machine, and assessed in sand liquefaction from virtue data of some fields in home and overseas with the tool Libsvm, which was programmed based on the support vector machine theory. And got a good coherency between the assessement results and the actual liquefaction. The research expresses that the extension assessment method and the support vector machine are useful tool in the assessment and prediction of sand liquefaction potential.更多还原