| With the rapid development of the economy in China, in recent years the state has enlarged the national investment on infrastructure construction, especially the newly established high-speed railway. Since China has a vast territory, numerous and variegated rivers and developed river systems, high-speed railway is bound to spanning multitudinous rivers. The crossing bridges prove to be one of the most important river-crossing works in the railway engineering construction. In order to ensure the safety of flood-flowing, the construction project within the scope of administration of the waters have been required that the designing or construction should meet the state’s flood control standard’s requirements. To make comprehensive estimation of flood protection for a series of questions involving resisted-water, water-poured, regime stability, flood fighting and water conservancy during flood season which is caused by the projects is an important link proving feasibilities of the crossing bridges construction, which is the key to guarantee the security of flood-flowing, dyke and bridge projects and meanwhile is the key point of the department of water administration examining the construction of crossing bridges.Combining with engineering case of Xiangjiang Large Bridge in Xiangtan on Hu-Kun passenger transport line, this paper will discuss the basic problem of evaluating the impact of crossing bridges on the flood protection. Main contents and outcome of the study is presented as follows. Through the collection of the information of construction engineering design, hydrological data on the range of bridge and the knowledge of regional and river valley about Xiangjiang Large Bridge in Xiangtan on Hu-Kun passenger transport line, and on the basis of the state’s flood control standards and navigation standards, this paper analyses the effect of engineering construction on flood prevention security, from the analysis of resisted-water, water-poured on the range of bridge, analysis and estimation of hydrological and designing water level, under the condition of design flood. So as to learn affection of flood-flowing and regime stability after the bridge builds, flow fields on the range of bridge has been analyzed by adopting a two-dimensional mathematical model before and after the project construction. At last, through making adaptability analysis of the relationship and influence with now available Water Resources Planning, Standard for Flood Control and relative requirement, qualitative analysis of the influence of third party rights and construction has been undertaken. |
