共查询到20条相似文献，搜索用时 265 毫秒
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软基上的空心方块斜坡堤 总被引：6，自引：1，他引：5
根据实际工程需要,提出了一种适宜建造在软土地基上的新的空心方块斜坡堤型式。这种新型结构是利用各空心方块之间以及空心方块本身的空隙,降低堤身单位体积的重量以及堤身断面总重量,从而满足软土地基承载力和整体稳定的要求：结合长江口深水航道治理工程的北导堤堤头部位2．6km长的软基段,对空心方块斜坡堤的设计和试验研究情况作概要介绍。 相似文献
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悬浮物对鱼卵仔稚鱼的影响分析及其损失评估——以厦漳跨海大桥工程为例 总被引：1，自引：0，他引：1
以厦漳跨海大桥工程环境影响评价为例,分析工程施工期产生的悬浮物对鱼卵仔鱼的影响。依据2007年5月评价水域渔业资源调查资料,定量估算施工期悬浮物对九龙江口鱼卵仔稚鱼资源的损失量。结果表明,厦漳跨海大桥施工期悬浮物造成鱼卵资源损失量为14.0t;仔稚鱼资源损失量为96.8t。 相似文献
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目前在防波堤设计和施工中,较少考虑软粘土的蠕变特性对软土地基长期变形的影响.为准确预测斜坡堤软土地基的变形水平,研究采用Plaxis二维有限元程序,利用不考虑蠕变的摩尔-库仑模型和能反映土体时间效应的软土蠕变模型,模拟某斜坡堤地基软土层施工期和工后的地基变形过程,对比分析了两种不同模型的计算结果,表明由软土蠕变模型得到... 相似文献
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漫堤是天文潮、风暴潮与海浪等物理要素作用于海堤后海水翻越海堤的物理过程。本文利用天文潮-风暴潮-台风浪耦合模式(ADCIRC+SWAN)、基于非结构三角形网格和高分辨率地理数据(海堤位置和高程、岸线和水深等)构建福建沿海精细化漫堤风险等级评估系统。该系统在近岸网格分辨率最高达50m,可精确刻画福建沿海复杂地形。利用模拟的水位与海浪参数,采用波浪爬高公式计算得到各海堤堤前波浪爬高。按照总水位与波浪爬高之和与海堤高程的对比,将漫堤风险分为五个等级。对2013年的超强台风天兔过程进行后报检验。结果显示,该系统计算的漫堤情况与灾后调查的漫堤实况基本一致,结果准确,说明本研究中采用的漫堤风险评估标准和方法是可行的。在此基础上,设计了4种不同的台风强度等级,对福建沿海206条海堤进行了漫堤风险等级评估,探究台风强度对漫堤风险的影响。结果表明:波浪爬高对漫堤风险的影响高于单纯的风暴潮增水;风暴潮增水随台风强度的增强增量较小,对于漫堤的风险影响较小;福建沿海波浪爬高普遍较高,随着台风强度的增强,波浪爬高会显著增加漫堤的风险等级,且应重视台风浪对海堤造成的冲击所导致的溃堤灾害。本研究可为沿海防灾减灾提供科学依据。 相似文献
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无口门式潜堤蓄泄系统中水流属于非恒定流,其蓄泄问题以及堤后坝田内的水位问题关系到潜堤的保滩促淤效果以及堤身的结构稳定性,外海潮位的交替变化对潜堤蓄泄系统的非恒定流调节影响较大,其蓄泄特征较复杂,文中以水量平衡原理为基础,结合外海潮位特性,建立不同情况下坝田内水位变化的解析方法,通过对工程实例计算验证,分析不同的潜堤方案对坝田内水位的影响,结果表明,该方法可以合理地模拟潜堤后坝田内的水位变化过程. 相似文献
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Risk analysis and assessment relating coastal structures has been one of the hot topics in the area of coastal protection recently. In this paper, from three aspects of joint return period of multiple loads, dike failure rate and dike continuous risk prevention respectively, three new risk analysis methods concerning overtopping of sea dikes are developed. It is worth noting that the factors of storm surge which leads to overtopping are also considered in the three methods. In order to verify and estimate the effectiveness and reliability of the newly developed methods, quantified mutual information is adopted. By means of case testing, it can be found that different prior variables might be selected dividedly, according to the requirement of special engineering application or the dominance of loads. Based on the selection of prior variables, the correlating risk analysis method can be successfully applied to practical engineering. 相似文献
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A series of hydraulic model tests are carried out to investigate random wave run-up and overtopping on smooth, impermeable single slope and composite slope. Based on analysis of the influences of wave steepness, structure slope, incident wave angle, width of the berm and water depth on the berm and the wave run-up, empirical formulas for wave run-up on dike are proposed. Moreover, empirical formula on estimating the wave run-up on composite slope with multiple berms is presented for practical application of complex dike cross-section. The present study shows that the influence factors for wave overtopping are almost the same as those for wave run-up and the trend of the wave overtopping variation with main influence parameters is also similar to that for wave run-up. The trend of the wave overtopping discharge variations can be well described by two main factors, i.e. the wave run-up and the crest freeboard of the structure. A new prediction method for wave overtopping discharge is proposed for random waves. The proposed prediction formulas are applied to case study of over forty cases and the results show that the prediction methods are good enough for practical design purposes. 相似文献
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Zhou Jiabao Zhang Jiachang Senior Engineer River Harbour Department Nanjing Hydraulic Research Institute Nanjing 《中国海洋工程》1992,(1)
-The effect of wave group on wave run-up on a slope dike is mainly discussed in this paper. Two simulating methods of wave group and their applications in laboratory are introduced. Synthesizing the research results of wave run-up on a slope dike, the effect of wave group on wave run-up on a slope dike in coastal protection engineering is studied as the main point. 相似文献
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The Nampo dike, which is located at the west coast of Korea, was destroyed by wave overtopping during the storms on 30 August and 17 September in 1959. In this paper, is performed the probabilistic assessment of wave overtopping of Nampo dike by use of Owen model, Van der Meer ＆ Janssen model and Hedges ＆ Reis model for wave overtopping of seawall. Based on the available tidal and wave data for storm surges in 1989, the risk assessment of wave overtopping of the Nampo dike has been carried out by both Level Ⅱ and Level Ⅲ reliability methods. The calculated resuhs show the general agreement of failure probability between the two methods. By utilizing the rehabilitated cross section of Nampo dike, the failure probability of wave overtopping for the Nampo dike after rehabilitation will be rapidly reduced to that of initial design at crest level of 9.0 m with the improved slope from 1 ： 2 to 1 ： 4 at seaside. Since the sea level may only rise 1.0 m in the next few decades, the failure probability of Nampo dike will be still in the safe range. 相似文献
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Seok Lee Heung-Jae Lie Kyu-Min Song Cheol-Ho Cho Eun-Pyo Lim 《Journal of Oceanography》2008,64(5):763-776
This study examined tidal modification and change in tidal currents caused by the construction of the Saemangeum dike, based
on field observations and a numerical model. The Saemangeum dike was completed in April 2006, enclosing an estuarine area
along the mid-western coast of South Korea. After closure of the dike, the tidal range outside the dike decreased slightly
but significantly, while the inside tidal range decreased drastically. The numerical model results show that the dike construction
has influenced tidal energy propagation and the tidal system in the Yellow Sea. The tidal current speed near the dike decreased
abruptly following closure of the dike, except in front of the sluice gates. Since completion of the dike, outflow water discharged
from the sluice gates has longer residence times due to the weakened tidal current; the change in the tidal current field
has also caused greater northward expansion of outflow water. The sluice gates release fresher water, which spreads over the
sea surface mainly by inertial momentum near the gate; this water is then gradually mixed with sea water farther from the
gate. The less saline, possibly more contaminated outflow impacts the marine environment near the Saemangeum dike. Controlling
the discharge and gate-opening timing can partially mitigate these impacts on the marine environment. 相似文献
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海洋工程全面风险管理方法体系研究 总被引：1，自引：0，他引：1
文中将国际最新的全面风险管理理念引入到海洋工程项目中,按照风险分析、风险评价、风险决策、风险监控四个阶段,从定性与定量两方面,对风险管理常用各种方法的起源发展、涵义、适用及优缺点等进行分析比较、归纳总结,建立了客观、科学、系统、动态的海洋工程项目的全面风险管理方法体系。 相似文献
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Dike resilience against wave overtopping has gained more and more attention in recent years due to the effect of expected future climate changes. The overtopping flow velocities and flow depths on dikes have recently been studied in 2D small-scale experiments. This has led to semi-empirical formulae for the estimation of flow depths and flow velocities across a dike. The results have been coupled to the actual erosion of the landward dike slope determined by full-scale 2D tests using the so-called “Overtopping Simulator”. This paper describes the results from 96 small-scale tests carried out in a shallow water basin at Aalborg University to cover the so far unknown 3D effects from oblique long-crested and short-crested waves. Based on results from the laboratory tests, expansions are proposed to the existing 2D formulae so as to cover oblique and short-crested waves. The wave obliquity is seen to significantly reduce the overtopping flow velocities and flow depths on especially the landward slope of a sea dike. Moreover, the tests showed that the average flow directions on the dike crest from oblique long-crested and short-crested waves correspond approximately to the incident wave direction. Flow depths and the squared flow velocities on the dike are concluded to be Rayleigh-distributed in case of both long-crested and short-crested waves for all considered incident wave obliquities. Findings in the present paper are needed to obtain more realistic estimates of dike erosion caused by wave overtopping. 相似文献