中美抗震设计规范主要地震动参数的对比研究

通过对中美抗震规范中抗震设防标准、建筑物类别、场地类别、用于结构设计的地面运动取值及特征周期等参数的对比分析,表明由于中美规范抗震设计理念的差异,在确定抗震设防的基准地震及用于结构设计的地面运动取值时具有不同的地震危险性特征,同时给出中美规范建筑物类别、场地类别划分的差异及对应关系,比较了中美规范确定特征周期的相关影响参数,提出中美规范主要地震动参数的相互转换方法,可为今后海外项目抗震设计提供参考。     

水闸闸室抗震动力分析及措施

在水闸闸室抗震设计中,为充分考虑闸室结构空间振动的耦联影响,建立了能反映闸室结构实际情况的空间三维计算模型,采用振型分解反应谱法对闸室结构进行了抗震动力计算,并以嶂山闸闸室为例,结合闸室结构地震作用效应的分析结果,提出了有针对性的抗震措施,达到了减小地震作用效应、增强闸室抗震性能的目的。     

某泄洪水闸上部结构动力响应分析

大量震害表明水闸上部结构是地震作用下易发破坏部位,然而规范并未对其抗震性能作专门要求,众多水闸设计中并未将上部结构与主体结构作为整体分析。以西北某水闸为例,采用动力时程法分别计算了水闸整体结构、下部主体及上部结构的动力响应,对比分析了各个结构的动力响应,探讨了上部结构与下部结构之间的相互作用。结果表明,相比于单独承受地震作用,上部结构和下部结构作为一个整体时,水闸会出现显著的鞭梢效应,且下部结构的地震能量会向上部转移。建议水闸设计时考虑上部结构的影响。     

水闸抗震性能评价模型研究

为进一步研究水闸抗震性能评价方法,首先根据规范和设计标准建立水闸抗震性能评价指标体系,然后分别借助改进群组G2法和独立信息数据波动法计算主客观指标权重,使用最小鉴别信息原理进行权重融合,获得较为科学合理的评价指标融合权重值,在此基础上,构建评价水闸抗震性能的可拓物元模型,最后利用该模型评价实际水闸工程的抗震性能。结果表明,模型计算的水闸抗震性能评价结果与实际相吻合,验证了该模型的可行性。     

紫坪铺“5.12”震害对面板堆石坝抗震措施的若干启示

结合面板堆石坝设计规范的修编工作,总结分析了"5.12"汶川地震中紫坪铺面板堆石坝的震害特征,获得了关于面板堆石坝抗震措施的若干启示,包括坝顶及其附近坝坡的防护、面板垂直缝的抗挤压措施和水平施工缝的抗震设计、面板堆石坝的地震变形控制及基于抗震计算和工程经验确定抗震措施的重要性等,对做好面板堆石坝抗震措施具有重要意义。     

中孟基本风速及地震动主要参数对比

通过对中孟规范基本风速定义中的地面粗糙度类别、标准高度、重现期、时距等要素进行逐一对比分析,得出两国规范中基本风速定义的异同,并进一步探讨了两国规范间基本风速的转换方法。另外通过对中孟规范中的地面峰值加速度、地震超越概率、抗震设防目标等进行对比,进而提出了在孟加拉项目中如何将孟加拉规范的地震动参数转换为中国规范进行设计的建议。可为今后孟加拉项目的风荷载和地震荷载设计提供参考。     

基于任意滑动面的糯扎渡堆石坝稳定验算

以西部强震区糯扎渡高心墙堆石坝为例,采用拟静力抗震安全系数和Newmark刚塑体滑移量验算了动力稳定性,基于工程实际确定由若干变量控制的任意滑动面,采用Morgenstern-Price法计算安全系数,并结合和声优化算法搜索坝坡在地震荷载作用下的临界滑动面度相应安全系数,依据Newmark滑移法确定滑动体的地震滑移量.分析结果表明,该坝滑移量超过标准,建议坝顶部位应采取加固措施.     

核电站常规岛主厂房结构抗震性能设计

核电站常规岛主厂房结构布置受限于工艺流程,含较多的错层、跃层,使结构的刚度与质量分布严重不均匀,往往超过了规范的适用条件,地震期间若出现功能中断或设备受损都将造成巨大的损失。基于性能的抗震设计应用于主厂房结构的抗震设计与评估中,在承载力和变形能力两个方面量化其抗震水平,确保主厂房的抗震能力满足预期设防目标。承载力依据现行抗震规范设计,变形能力的评估细化到构件的层次进行,在此基础上选取了5条地震波记录对典型常规岛主厂房结构进行弹塑性分析。结果表明:核电站常规岛主厂房结构能够在地震作用下保持不倒塌,结构具有较大冗余度,能保证核岛安全。     

长江河口段潮位预报及实时校正模型

针对长江河口段潮位周期性变化规律,采用调和分析法建立了潮汐预报模型,根据对分析期若干年潮位推算揭示了误差与上游径流闻关系,并建立了以上游大通水文站实测流量为输入的实时校正模型.潮汐预报模型与实时校正模型相结合,既可提前预知长江河口段的水情,又能根据动态掌握的大通流量信息对前期预报结果实时校正以提高预报精度,对类似河段的潮位预报具有参考价值.     

鲁皂水库重力坝地震动力响应分析

为分析软弱地基上溢流坝的抗震安全性能,以贵州省兴仁县鲁皂水库重力坝为例,基于流固耦合理论,考虑地震作用下库水和大坝之间的相互作用,建立了溢流坝段有限元模型,采用时程法进行地震动力分析,获得了坝体动应力、动位移和加速度的分布规律,并将水工建筑物抗震规范中的振型分解反应谱法与时程法的计算结果进行对比。结果表明,该工程具有良好的抗震安全性能。     

平原感潮河网地区边界水闸流量计算方法

鉴于平原感潮河网地区边界水闸流量计算方法的重要性,介绍了在线监测、水文水动力学模型、水力学及多元回归法过流公式3种水闸流量计算方法,并通过计算上海市浦东新区典型闸门流量过程,提出了应根据闸门重要性、监测仪器安装条件、投入预算、流域数据信息掌握程度、技术人员能力级别等因素来选取最优的水闸流量计算方法。     

某水闸地基桩基础与沉井基础方案优化选择

针对深基础水闸结构地基处理方案的比选未能考虑结构间相互作用的问题,以江苏省沿海某挡潮闸为例,利用ANSYS软件分别建立了考虑闸室、基础和地基的三维有限元整体模型,分别对钻孔灌注桩基础和沉井基础两种地基处理方案的水闸整体结构进行了计算分析,推荐沉井基础方案为最优方案。建议在实际工程设计中采用三维空间有限元法进行深基础水闸结构地基处理方案的比选。     

徐楼闸深厚粉细砂闸基防渗防冲方法及处理效果

鉴于徐楼闸老闸因闸基渗透、上下游冲刷而损坏,移址改建的徐楼闸新闸必须解决闸基深厚粉细砂层渗透能力强、不耐冲刷的问题,采用闸基换填水泥土、闸基设置截渗墙、下游消力池末端设置防冲墙等加固补强措施,就可有效减弱粉细砂的渗透问题,并可有效提高闸基的抗冲能力,从而确保闸基稳定安全运行。     

低水头多孔闸调度水力冲淤模型试验研究

双台子河闸位于辽河下游感潮河段,枢纽工程中的新建浅孔闸为低水头高淹没度的拦潮闸。由于受到海潮的影响,在涨潮时,海水携带大量的泥沙并沉积在闸下,导致拦潮闸下游处于淤积的状态,下游河床由于淤沙的沉积而不断抬升。为有效解决河道抬升及淤沙问题,在水工模型试验的基础上,通过多种闸门调度运行方案并结合定床和动床调度试验,测量和分析了不同闸门开启方式下的流速、流态等水力要素及动床冲刷情况,得到科学合理的闸门调度方案,即隔孔开启,可有效改善双台子河闸闸下淤沙问题。     

Experimental investigation on the relationship between sluice caisson shape of tidal power plant and the water discharge capability

The change of water discharge capability of the sluice caisson of tidal power plant according to the change of geometrical shape of the sluice caisson was investigated by performing laboratory experiments. The major design parameters that constitute general shape of the sluice caisson were deduced and a total of 32 different shapes of sluice caisson models were subjected to the hydraulic experiments. For every sluice caisson model, the water discharge capability was estimated with five different flow rates and three different water level conditions. The experiments were carried out in an open channel flume with a great care to measure flow rate and water level accurately, which are key physical quantities in estimating the water discharge capability of the sluice caisson models. By analyzing the experimental results, influence of the respective design parameters on the performance of the sluice caisson was examined and the general guidelines to enhance the water discharge capability were suggested. The discharge coefficient of the best sluice caisson model ranged from 2.3 to 3.1 depending on the experimental conditions, which is far higher than the values that were adopted in the past feasibility studies in Korea.     

广州市芳村片感潮河网水体交换规律数值分析

为改善广州市芳村片河网水质质量并研究城市内河涌与外江之间的水体交换规律,基于Saint Venant方程组和对流扩散方程,建立了感潮河网一维水流水质数值模型,并对模型进行了率定。针对实测水质数据普遍较少的问题,引入了基于污染物相对浓度的水体交换指标,发展了一种简便有效的水环境调控评判方法,计算分析了河涌连通、水闸调度、水闸建设等措施对河网水体交换的影响,提出了芳村片引清调水的优化方案。模拟结果表明,该方法可用以制定、优化调水方案并为区域水系规划和建设提供依据。     

Optimization modelling of the impacts of a Severn Barrage for a two-way generation scheme using a Continental Shelf model

The Severn Estuary has the world's second largest tide range and a barrage across the estuary, located just seawards of Cardiff in Wales and Weston in the South West England, has been proposed for over half a century, with the objective of extracting large amounts of tidal energy. A Severn Barrage, as previously proposed by the Severn Tidal Power Group (STPG), would be the largest renewable energy project for tidal power generation in the world, if built as proposed, and would generate approximately 5% of the UK's electricity needs. However, concerns have been raised over the environmental impacts of such a barrage, including potential increase in flood risk, loss of intertidal habitats etc. In addressing the challenges of maximizing the energy output and minimizing the environmental impacts of such a barrage, this research study has focused on using a Continental Shelf model, based on the modified Environmental Fluid Dynamics Code (EFDC) with a barrage operation module (EFDC_B), to investigate both the far and near field hydrodynamic impacts of a barrage for different operating scenarios. Three scenarios have been considered to simulate the Severn Barrage, operating via two-way generation and using different combinations of turbines and sluices. The first scenario consisted of 216 turbines and 166 sluices installed along the barrage; the second consisted of 382 turbines with no sluices; and the third consisted of 764 turbines and no sluices. The specification of the sluice gates and turbines are the same for all scenarios. The model results indicate that the third scenario has the best mitigating effects for the far-field and near-field flood risks caused by a barrage and produces the most similar results of minimum water depth and maximum velocity distributions to those obtained from simulating the natural conditions of the estuary, i.e. the current conditions. The results also show that the flow patterns around the barrage are closest to those for the existing natural conditions with minimal slight changes in the estuary. Thus, the results clearly indicate that the environmental impacts of a Severn Barrage can be minimized if the barrage is operated for two-way generation and under the third scenario. Although it appears that the energy output for the third scenario is less than that obtained for the other two scenarios, if very low head (VLH) turbines are used, then the third scenario could generate more energy as more turbines could be cited along the barrage structure. Therefore, the study shows that a Severn Barrage, operating in two-way generation and with 764 turbines (ideally VLH turbines), would be the best option to meet the needs of maximizing the energy output, but having a minimal impact on environmental changes in the estuary and far-field.     

Three-dimensional experiment and numerical simulation of the discharge performance of sluice passageway for tidal power plant

In this study, the discharge performance of the sluice passageway of tidal power plants was investigated based on the experiments conducted in a planar open channel and three-dimensional numerical simulations. By conducting the experiments in a planar channel, it was possible to reproduce the three-dimensional flow field around the sluice passageways similar to the field condition. The discharge capability of the passageway was estimated under various flow conditions with five different channel bathymetries. The estimates of the discharge coefficient generally ranged from 1.3 to 1.45, which are significantly smaller than the values obtained from the previous study based on the two-dimensional experiment. In addition, the experimental results showed a considerable difference in the discharge coefficient among the test cases, demonstrating an apparent influence of channel bed topography on the discharge performance. Based on an intensive parametric study carried out using the numerical simulations, an optimal configuration of the width, slope, and bottom length of the apron section was suggested for maximizing the discharge capability of the sluice passageway.