摘要
施工导流是水利水电工程建设中的一项重要工程内容,它贯穿整个工程的始终,并对整个工程能否顺利进行起着举足轻重的作用。随着我国水电工程建设发展,一批病险水库需要加固或重建,对于大型重建水电工程,利用原大坝挡水是一种较为经济的导流方案,对于这种导流方案的风险分析,原来的基于新建工程的施工导流风险分析方法能否适用是一个值得研究的问题。
另外,随着全球环境的变化,极端天气事件时有发生,考虑极端天气条件下施工导流风险分析问题也是一个值得重视的问题。基于以上问题,本文主要开展了以下方面的研究:
⑴针对新建水利水电工程的施工导流,分析了影响工程建设和导流风险的各种不确定性随机因素及其分布,综合比较了多种风险计算方法,最终基于蒙特卡洛方法建立了导流风险计算模型。
⑵针对大型重建水利水电工程不同于新建工程的特点,对重建工程施工导流的风险重新定义并修改风险计算模型。
⑶由于天气变化改变全球水文循环,导致水资源的时空分布发生变化,降水的变化会影响径流形成从而导致洪水过程的改变,这对水利水电工程施工导流具有直接的影响,因此有必要分析我国未来降水的变化趋势。
⑷以一个利用原大坝作为上游围堰进行施工导流的重建工程作为实例,结合该类工程施工导流风险定义和应考虑的因素,应用本文提出的相应的导流风险分析方法,计算施工期某一导流方案的风险率并对结果做出分析。
Construction diversion is a significant part of hydraulic engineering project construction which is a key factor of whole project that carries through from beginning to end of the whole construction process. Numbers of dangerous reservoirs need to be reinforced or rebuilt as the hydraulic engineering developed rapidly in our country. Using the primary dam to retain water is an economical diversion scheme for large reconstruction hydraulic engineering project of. This topic deserves to be studied whether the risk analysis of diversion scheme in new project is suitable to that in reconstruction project.
Besides, extreme weather happens from time to time, risk analysis of construction diversion which considers the extreme weather is also desirable to be discussed.
According to the problems mentioned above, works in following aspects have been done:
⑴Analyzing the stochastic uncertainty factors that influence the construction and diversion of new projects and their distribution. Constructing the risk calculation model of diversion based on Monte-Carlo method according to comprehensive comparison of several risk calculation methods.
⑵Redefining the risk analysis of construction diversion in reconstruction project and modifying the risk analysis calculation model based on the characteristics of large reconstruction hydraulic engineering project that different from new project.
⑶Spatial and temporal distribution of water resource varies for the variation of weather that leads to the change of global hydrological cycle. Variation of precipitation influences the variation of flood by influencing the form of flow which has direct impacts on diversion in hydraulic engineering construction. Hence, it is necessary to analyze the trend of future precipitation in our country.
⑷Calculating the risk rate of diversion scheme and analyzing the results by using the risk analysis method proposed in this paper based on an example of construction diversion in hydraulic reconstruction engineering project which regard the primary dam as upstream cofferdam while considering the characteristics of diversion in this type of project.
引文
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