CAJ | 학술논문

河口大型围垦工程围区吞吐潮量大,河口滩势条件复杂,龙口位置选择和极值流速确定是工程设计中的关键环节.以两个典型河口大型围垦工程龙口为例,从水动力分析角度提出合理的龙口平面选址和龙口渡汛时因地制宜的结构布置.在青草沙水库工程中,龙口位置的确定充分利用围区原有深槽的过流能力,以保证库区内外及时水交换,并兼顾到围堤实施顺序与工程区整体河势环境相协调,避免口门进出水引起工程河段滩地的大冲大淤,也确保了堤基安全.龙口渡汛需要面临长时间大潮汛过流考验,龙口流速大小决定了龙口结构的保护方案和后期的合龙方案,常规使用的堰流计算方法能较为准确地计算龙口流量和断面平均流速过程,数值模型能对大型龙口流速空间分布情况进行很好的模拟,是常规计算方法的重要补充.计算结果表明口门横向上中心流速大于口门两侧流速,在纵向上底坡内外两侧顶角处水流受重力作用加强,垂向断面收缩,在涨、落急时刻分别形成大流速区,是龙口结构布置时重点抗冲保护区域,需要设置抗冲性较强、自重大且联接牢固的护面材料.此外,同一潮周期内涨急流速通常大于落急流速也是其重要水动力特点.
하구대형위은공정위구탄토조량대,하구탄세조건복잡,룡구위치선택화겁치류속학정시공정설계중적관건배절.이량개전형하구대형위은공정룡구위례,종수동력분석각도제출합리적룡구평면선지화룡구도신시인지제의적결구포치.재청초사수고공정중,룡구위치적학정충분이용위구원유심조적과류능력,이보증고구내외급시수교환,병겸고도위제실시순서여공정구정체하세배경상협조,피면구문진출수인기공정하단탄지적대충대어,야학보료제기안전.룡구도신수요면림장시간대조신과류고험,룡구류속대소결정료룡구결구적보호방안화후기적합룡방안,상규사용적언류계산방법능교위준학지계산룡구류량화단면평균류속과정,수치모형능대대형룡구류속공간분포정황진행흔호적모의,시상규계산방법적중요보충.계산결과표명구문횡향상중심류속대우구문량측류속,재종향상저파내외량측정각처수류수중력작용가강,수향단면수축,재창、락급시각분별형성대류속구,시룡구결구포치시중점항충보호구역,수요설치항충성교강、자중대차련접뢰고적호면재료.차외,동일조주기내창급류속통상대우락급류속야시기중요수동력특점.
The closure gap which is characterized by high velocity and being hard to be closed is often the most concerned construction part of the whole reclamation project. Two engineering examples are introduced in this paper to describe hydrodynamics at the gap section in large-scale estuarine cases. Selection of reasonable location of the closure gap and its structural layout is also analyzed in view o f its hydrodynamics. To minimize the negative impact on the neighboring beach for the large amount of current effuse from and into the embanked area, which may cause erosion and siltation around the project area, the gap to be closed is preferred to be positioned at a relatively deep outlet where current direction conforms to the neighbouring river flow. Two and three dimensional numerical models were implemented and the results indicate obvious uneven distribution of its velocity on the gap platform, which the empirical weir theory, a familiar and predominantly used method, may not take into consideration. Furthermore, the extreme velocity at the upper corner around the two sides of the gap protection layer should be considered during the design and construction phase.