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黄河河曲段冰塞水位的分析计算 总被引:2,自引:0,他引:2
本文根据黄河河曲段6年的实测资料,分析了该冰塞河段冰期水位的变化规律,讨论了该河段冰塞水位的变化与冰塞演变的相互关系。建立了冰塞水位变化的参数关系式,基于原型的观测研究,对试验室模拟冰塞的水位进行了分析研究,研究表明:试验室模拟冰塞水位的变化规律与天然河道中冰塞水位的变化规律相同。由此,可以进行冰塞水位的计算及其预报。 相似文献
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冰塞的出现使上游水位壅高,极易诱发凌洪灾害。桥墩墩型是影响桥墩附近冰塞壅水的重要因素之一。通过模型试验,对不同墩型影响下的平衡冰塞水位增值过程进行研究,并与无桥墩条件和明流情况进行了对比。试验结果表明:在试验冰水流量比条件下,当Fr≤0.145时,无桥墩条件下平衡冰塞水位增值小于有桥墩;当Fr>0.145时,无桥墩条件下平衡冰塞水位增值大于有桥墩;桥墩墩型引起的平衡冰塞水位增值由大到小排序为长方形桥墩、尖端形桥墩、圆端形桥墩和圆柱形桥墩。易发生冰塞的河段,建造桥梁时应当尽量选用圆柱形、圆端形桥墩。 相似文献
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采用聚乙烯颗粒为天然冰模拟材料,对桥墩影响下的冰塞水位变化规律进行了探索性试验研究.试验发现,有桥墩时,冰塞演变可分为冰塞越过桥墩和未越过桥墩两种情况;冰塞动态演变过程中,桥墩附近冰塞底部存在冲刷现象,由此产生的冲刷输冰流量会引发较为复杂的冰塞水位演变过程.研究表明,有桥墩条件下,水力及来冰量条件对平衡冰塞时的水位增值影响规律与无桥墩时基本一致;水流条件和来冰流量相同条件下,当冰塞能越过桥墩达到平衡时,墩径较大时水位增值也较大,在断面阻塞程度相同条件下,双墩水位增值大于单墩. 相似文献
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万家寨水库冰塞计算方法探讨 总被引:1,自引:0,他引:1
通过对冰塞体的受力分析找出影响冰塞河段稳定流速的因素, 利用万家寨水库冰塞实测资料建立了稳定流速计算的经验关系式.稳定流速计算公式与有压管流能量方程联解求出各断面测压管水位和冰盖底部高程, 根据浮力原理求出冰塞河段的冰面高程.经实测资料验证, 结果精度较好, 达到设计要求. 相似文献
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Forecast of water level and ice jam thickness using the back propagation neural network and support vector machine methods 总被引:1,自引:1,他引:0
J. Wang Ph.D. J. Sui Ph.D. L. Guo M.Sc. B. W. Karney Ph.D. R. Jüpner Ph.D. 《International Journal of Environmental Science and Technology》2010,7(2):215-224
Ice jams can sometimes occur in high latitude rivers during winter and the resulting water level rise may generate costly and dangerous flooding such as the recent ice jam flooding in the Nechako River in downtown Prince George in Canada. Thus, the forecast of water level and ice jam thickness is of great importance. This study compares three methods to simulate and forecast water level and ice jam thickness based on field observations of river ice jams in the Quyu Reach of the Yellow River in China. More specifically, simulation results generated by the traditional multi-variant regressional method are compared to those of the back propagation neural network and the support vector machine methods. The forecast of ice jam thickness and water level under ice jammed condition have been conducted in two different approaches, 1) simulation of water level and ice jam thickness in the second half of the period of measurement using models developed based on data gained during the first half of the period of measurement, 2) simulation of water level and ice jam thickness at the downstream cross sections using models developed based on data gained at the upstream cross sections. For this reason, as the results of simulation and field observations indicated, the back propagation neural network method and the support vector machine method are superior in terms of accuracy to the multi-variant regressional method. 相似文献
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黄河流域地形地貌相差悬殊,受西伯利亚和蒙古一带冷空气的影响,冬春季干、支流有不同程度的冰情出现.由于黄河凌情来势迅猛,水位急剧壅高,易决口成灾,开展冰凌预警研究是十分必要的.黄河封河期冰盖下流凌量及冰塞体的生长状况是黄河冰凌预警的关键要素,采用地电测试技术,对冰水两相流进行视电阻率测量,绘制电测深曲线,数字化模拟冰凌参数,评估冰塞体的生长及冰块堆积状况,为防凌减灾提供预警服务.测试结果表明,平稳流凌时,测深曲线经子波分解后阈值为10Ω·m左右,当出现局部冰塞时阈值达到100Ω·m左右,数值易于区分,基于电测深曲线的差异性进行冰凌预警的方法是可行的,可为防凌减灾提供预警服务. 相似文献
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A large river ice jam and associated flooding in February 1996 on the Blackfoot and Clark Fork Rivers of western Montana
mobilized large amounts of fine-grained sediment. Metal concentrations in sediment downstream from a reservoir containing
large amounts of contaminated sediment were enriched in metals after the ice jam, while open reaches above the reservoir were
diluted by ice-jam processes. This varied response shows the importance of understanding ice jam events to sediment and metal
transport and suggests that ice jams must be considered as important agents affecting sediment metal concentrations in rivers.
Received: 4 December 1997 · Accepted: 23 February 1998 相似文献
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1997年3月29日额尔齐斯河南湾水文站发生了有记录资料(1985年12月至今)以来唯一一次特殊“武开河”解冻冰情现象,冰情极其特殊且影响后果严重,有必要全面分析其特殊冰情现象、特征及其影响因素。利用“1997·3·29”推冰前后的实测冰情、气温、水位等资料,对特殊“武开河”推冰现象、特征及其主要影响因素进行分析,结果显示:相较于其他年份解冻期气温缓慢稳定上升,这次“武开河”推冰现象发生前气温偏低;受气温转正时间短,气温偏低和冰厚较厚因素制约,“武开河”冰情发生前整个河流断面无推冰迹象,岸边无融冰,只有冰上流水现象;上游开河略早,来水量增加迅猛。“武开河”发生与最大冰厚间无必然因果关系,但上游来水量的急剧增加,水位快速上涨对于“武开河”解冻冰情现象的发生起了决定性作用。新疆阿勒泰地区发生冰凌溃坝型洪水的风险较低,对冰凌灾害的研究与预防方面应主要加强对推冰现象及过程的研究与预警方面。 相似文献
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