Hydraulic model tests for propagation of flow and sediment in floods due to breaking of a natural landslide dam during a mountainous torrent     

Takahiro Itoh  Akihiko Ikeda  Takahiko Nagayama  Takahisa Mizuyama 《国际泥沙研究》2018,33(2):107-116

During mountain torrents, large-magnitude floods may result from heavy rainfall and cause the breakage of landslide dams naturally formed by heavy rainfall, earthquakes, and so on. The characteristics of longitudinal spreading of clear water discharge and changes in flow depth must be clarified because the changes in peak depth have not yet been examined in steep-slope torrents and because there are few data on spreading of flash floods and related sedimentation in mountainous torrents. In the present study, experimental data were collected through hydraulic model tests over a rigid bed, and the spreading of water, fine sediment, bed load, and large boulders due to flooding are discussed assuming that flash flooding/debris flows occur in the upstream reach. The effects of changes in flow width, such as expansions and contractions in the flow width, as well as changes in meandering channels, sediment transportation, and spreading flow depth resulting from bores are examined using flume data for a steep-slope torrent. The data obtained in the present study reveal that fine sediment components are transported to the downstream reach if large-magnitude floods occur and that the spreading rate and peak lags of the fine sediment and water level indicate the occurrence of a flood in the upstream reach.  相似文献   

水运工程多波束测深作业要求的研究     

毛世伟  黄永军  付兴武 《海洋测绘》2011,31(3):44-47

对水运工程多波束测深作业要求中一系列的技术问题进行了深入研究.以满足波束脚印无缝衔接和探寻水底目标物为约束,分别给出了测船最大限速的计算式.通过数值分析探讨了目前几种常用多波束仪器测线布设的理论宽深比和实际宽深比.对影响多波束测深精度的五个重要参数:横摇偏角、纵摇偏角、艏摇偏角、时延、声速剖面等分别做了详细介绍,并且给...  相似文献   

地下掩埋管道及其地下建筑物压覆矿产边界的确定          下载免费PDF全文

巩庆伟  李进喜  吉恒召 《山东国土资源》2009,25(3)

地下掩埋管道及其地下建筑物压覆矿产边界，是由建设工程本身抗破坏能力、工程重要性以及矿体特征、开采方式、工程与矿体的相对位置等因素决定的。对于地下矿体，按围护带宽度、上覆各岩层移动角确定压覆矿产边界；对于地表非爆破性采矿，按围护带宽度和地表岩层移动角确定压覆矿产边界；对于地表爆破性采矿，安全爆破距离一般取50m。  相似文献   

风浪频谱的成长模型Ⅰ.谱参量随风区的增长关系          下载免费PDF全文

王鑫  侯一筠 《海洋与湖沼》2008,39(5):433-438

为得到谱参量随风区的变化关系,从而更细致地刻画风浪频谱的成长方式.在动力学方程的控制下,基于三参量风浪频谱,利用动力-统计学相结合的方法导出了谱参量(谱宽度B、谱的零阶矩～m0、谱的峰频率～ω0)随风场要素(风区)的成长关系分别为:B=5.68×10-3～X9.482×10-1-4.66×10-2ln-x;～m0=1.356×10-8～x2.367-1.097×10-1ln～x;～ω=4.082×101～X-7.623×10-1+3.71×10-2ln～x.同时得到了简化形式的波陡δ、波龄β与谱宽度之间的关系为:δ=2.14×10-2B-1.05-4.26×10-1lnB,β=1.26B1.28+1.97×10-1ln(B).此外,还得出了受风场要素控制的,谱的零阶矩与谱的峰频率之间新关系为:{ω0=a1～m0-0.33 a1=1.034×10-1～X1.872×10-2+8.50×10-4ln～x,从而阐明了先前的各种经验关系是新关系在取不同风区值时的特例.可见,将动力学原理引入风浪频谱的研究,所建立的谱参量随风区的变化关系与先前的经验公式相比更加合理,且普适性更强.  相似文献