苏通长江公路大桥桥区河床抗冲性能试验研究   总被引：1，自引：0，他引：1  

洪大林 谢瑞张思和  唐存本 《海洋工程》2003,21(4):91-96

针对交通、水利工程中遇到的实际问题，采用现场原状土取样，并通过封闭管道水力试验，得到原状土起动的临界切应力及冲刷率，并通过公式换算得到原状土的起动流速，这一方法可用来确定物理模型试验中动床模型设计参数，并可为设计部门提供科学依据。  相似文献   

灌河河口河道冲淤演变及航道自然条件分析     

刘玮祎  楼飞  虞志英 《海岸工程》2006,25(3):14-21

通过对近20 a实测水文地形资料的深入分析,得到了灌河干流河道及出口水道的冲淤演变规律:干流河道在盐东控制闸建闸前,以响水为界上段冲刷下段淤积,建闸后,从多年平均来看上段明显淤积下段冲刷;近10 a来,陈家港以下的干流河道弯道凹岸处均为深槽逼岸的冲刷区,且处在持续稳定冲刷状态;自20世纪80年代以来,灌河口外岸滩冲刷强度减弱,近10 a来,河口外冲淤近于平衡状态。这些研究为灌河口码头、航道等工程建设提供科学依据。  相似文献   

泥质河口闸下冲淤特性及冲淤量的分析预报   总被引：10，自引：2，他引：10  

王宏江 《海洋工程》2002,20(4):78-84

通过泥质河口建闸工程闸下淤积特性的分析研究表明,闸下河段淤积的条件是涨潮流带入河段的泥沙数量大于落潮流从河段内带走的泥沙数量。其水动力原因是径流量减小和潮波变形。在此基础上提出了建闸工程和建闸与双导堤相结合闸下淤积和冲刷的分析预报方法,这些冲淤分析预报方法得到了相关工程的实测资料及浑水动床物模试验结果的验证。  相似文献   

基于局部冲刷研究的大型圆柱周围波浪特性分析   总被引：2，自引：0，他引：2  

周益人  陈国平  王登婷 《海洋工程》2004,22(1):98-102

波浪环境下,大型圆柱的存在改变了周围原有波浪条件,直接导致局部冲刷。利用MacCamy和Fuchs的绕射理论对相对柱径较大(0.15相似文献   

Developing empirical formulas for assessing the scour of vertical and inclined piers     

H. Omara  G. M. Abdeelaal  K. Nadaoka  A. Tawfik 《Marine Georesources & Geotechnology》2020,38(2):133-143

Abstract

Because scour is one of the main reasons for bridge failure, this study focuses on accurately predicting the maximum scour depth around different vertical and inclined piers. Scouring is an issue of concern in the bridge design process, as most existing equations for predicting local scour near bridge piers suffer from over- or underprediction issues, resulting in higher foundation costs or bridge failure and inaccurate predictions of the scour around piers. The dimensionless maximum scour depths (y_s/D) of vertical and inclined piers were investigated for seven pier shapes with different L/D ratios and four inclination angles (θ) under shallow flow conditions. The inclined pier configuration reduced the y_s/D of the piers. The maximum y_s/D was observed for a rectangular pier with an L/D of 4.5 in both vertical and inclined configurations (θ of 10, 15 and 21°, respectively). The y_s/D was significantly decreased by increasing the angle of the pier from 10 to 30°. The y_s/D of the inclined rectangular piers decreased as θ decreased from 30 to 10° and the L/D ratio increased from 1 to 4.5. The best y_s/D results were obtained for inclined rectangular piers at a θ value of 30° and an L/D ratio of 7.5 compared to other shapes and inclination angles. New equations were developed to predict the local scour depth for circular, square and rectangular bridge piers. The equations yielded excellent results for predicting the maximum clear water scour depth around vertical and inclined piers with inclination angles of 10, 15, 21 and 30°, respectively.  相似文献   

Numerical Simulation of Wave Scour Around A Large-Scale Circular Cylinder     

ZHAO  Ming 《中国海洋工程》2002,16(4):513-523

A numerical model is developed for estimation of local scour around a large circular cylinder under vvave action. The model includes wave diffraction around structures, bed shear stress calculation inside the vvave boundary layer and topo-graphical change model. The vvave model is based on the improved Boussinesq equations for varying depth. The vvave boundary layer is calculaled by solving the integrated momentum equation over the boundary layer. The bed shear stress due to streaming, an important factor affecting the sediment transport around a large-scale cylinder, is calculated. The Lagrangian drift velocity is included in calculation of the suspended sediment transport rates. The model is implemented by a finite element method and the results from the present model, which agree well with experimental data, are com-pared vvith those from other methods.  相似文献   

大型桥梁冲刷防护工程损坏特性研究   总被引：2，自引：0，他引：2       下载免费PDF全文

高正荣  杨程生  唐晓春  俞竹青 《海洋工程》2016,34(2):24-34

以苏通大桥为例,通过模型试验和冲刷防护工程及周边河床地形的长期监测开展了大型桥梁冲刷防护工程的损坏特性研究。研究结果表明,大型桥梁冲刷防护工程存在两种损坏形式:防护工程防护区面层冲刷损坏和防护工程护坦边坡坍塌损坏;防护工程的破坏主要发生在防护工程后1~2年内。提出了以"损坏率"和"稳定边坡"分别表示两种不同类型的破坏指标。同时,提出了防护工程"成型稳定工程量基准线"概念,为监测冲刷防护工程稳定性制定定量目标。研究结果还表明,在防护体稳定后,防护区呈"洪季淤积、枯季冲刷"特点,这一变化对防护体稳定影响有限。研究结果为类似工程设计、监测、维护和相关研究提供参考。  相似文献   

粉沙海床管道在联锁排防护下的冲刷试验研究     

汪求顺  康海贵  孙英伟  莫仁杰 《海洋工程》2014,32(4):58-63

采用当地海床的天然粉沙进行试验床面的设计,对海底管道在实际海床受到的极限波浪和最大水流作用进行试验,在管道上方铺设混凝土联锁排,对联锁排块体稳定性和其对管道防护的有效性进行研究。通过物理模型试验,研究了在极限波浪和最大水流作用下,管道在粉沙床面最大冲刷深度。通过不同水深中波流条件下研究了混凝土联锁排防护效果及其周围床面的冲刷变化,观测了联锁排的稳定性。试验结果表明:按半经验半理论简化公式得出的联锁排厚度能满足稳定性的要求,比水利部规范计算的联锁排厚度偏大的公式更加适合应用,试验期间混凝土联锁排的排面稳定,能有效保护管道,在该防护下管道没有冲刷,只在联锁排上下游与床面接触的来流段和尾端有冲刷,但该冲刷深度不影响联锁排整体的稳定性。  相似文献   

Bridge pier failure probabilities under combined hazard effects of scour, truck and earthquake. Part I: occurrence probabilities     

Zach Liang  George C. Lee 《地震工程与工程振动(英文版)》2013,12(2):229-240

In many regions of the world, a bridge will experience multiple extreme hazards during its expected service life. The current American Association of State Highway and Transportation Officials (AASHTO) load and resistance factor design (LRFD) specifications are formulated based on failure probabilities, which are fully calibrated for dead load and nonextreme live loads. Design against earthquake loads is established separately. Design against scour effect is also formulated separately by using the concept of capacity reduction (or increased scour depth). Furthermore, scour effect cannot be linked directly to an LRFD limit state equation, because the latter is formulated using force-based analysis. This paper (in two parts) presents a probability-based procedure to estimate the combined hazard effects on bridges due to truck, earthquake and scour, by treating the effect of scour as an equivalent load effect so that it can be included in reliability-based bridge failure calculations. In Part I of this series, the general principle of treating the scour depth as an equivalent load effect is presented. The individual and combined partial failure probabilities due to truck, earthquake and scour effects are described. To explain the method of including non-force-based natural hazards effects, two types of common scour failures are considered. In Part II, the corresponding bridge failure probability, the occurrence of scour as well as simultaneously having both truck load and equivalent scour load are quantitatively discussed.  相似文献   

感潮河段丁坝局部冲刷三维数值模拟   总被引：1，自引：1，他引：0       下载免费PDF全文

张新周  窦希萍  王向明  王惠民  赵晓冬  徐雪松 《水科学进展》2012,23(2):222-228

针对局部冲刷和一般冲刷的不同,建立了考虑垂向水流作用的局部冲刷三维紊流泥沙数学模型,并对往复流和单向流作用下的丁坝局部冲刷进行了验证计算和数值模拟。结果表明,往复流作用下丁坝局部冲刷在冲刷过程和冲淤形态上与单向流有明显不同,若采用单向流作用下的局部冲刷模型试验结果来指导往复流作用下丁坝头防护工程的设计和施工是不利的。  相似文献