Vulnerability of Kuwait coast to sea level rise     

Mohammad M. M. Alsahli  Ahmed M. AlHasem 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2016,116(1):56-70

Assessing coastal vulnerability to sea level rise (SLR) at local and regional scales is a fundamental step for designing successful long-term coastal management plans. This study was thus designed to assess Kuwait coastal vulnerability to SLR at four scenarios (.5, 1, 1.5 and 2 m). Potential inundated areas and the number of people at risk were estimated based on these SLR scenarios. A coastal vulnerability index (CVI) map of Kuwait was then computed based on the lowest scenario using eight parameters: elevation, coastal slope, geomorphology, distance to 20-m isobath, population, land use, cultural heritage and transportation. The geographic distribution of inundated areas at an SLR of .5 m revealed that the northern islands of Kuwait and coastal areas along Kuwait Bay would be highly impacted, whereas the coastal area near Shuaibah Port was the most influenced among the southern coasts. Most of the coastal area exhibited a moderate vulnerability to SLR, especially the northern islands. This study presented an initial vulnerability assessment for Kuwait coasts to SLR, which can be extended with more variables. The integrated remote sensing and geographic information system methodology demonstrated in this study can be applied in similar studies elsewhere.  相似文献   

Diagnosis of earth-fill dams by synthesised approach of sounding and surface wave method     

Shin-ichi Nishimura  Toshifumi Shibata  Takayuki Shuku 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2016,10(4):312-319

The spatial distribution of the strength inside the earth-fill is identified by the sounding tests. In this research, the Swedish weight sounding (SWS) is employed, and the spatial high-density test is performed to identify the spatial correlation structure. Furthermore, the synthesised approach of the SWS and surface wave method, which is one of the geophysical method, is proposed to compensate the shortage of each approach. Consequently, the correlation structure of an earth-fill could be identified accurately, and the high resolution of the spatial distribution could be visualised based on the survey results.  相似文献   

Applying disk-based discontinuous deformation analysis (DDA) to simulate Donghekou landslide triggered by the Wenchuan earthquake   总被引：1，自引：0，他引：1  

S. Amir Reza Beyabanaki  Amvrossios C. Bagtzoglou  Lanbo Liu 《Geomechanics and Geoengineering》2016,11(3):177-188

In this paper, for the first time, disk-based discontinuous deformation analysis (DDA) is applied to simulate a real landslide triggered by an earthquake. For this purpose, the kinematic behaviour of the Donghekou landslide triggered by the Wenchuan earthquake is simulated and the results obtained using disk-based DDA are compared with actual data. The comparisons show that there is a good agreement between the results obtained using disk-based DDA and observed data. The simulation results provided an understanding of the failure behaviour and temporal evolution of the landslide. This study shows that disk-based DDA is a practical numerical tool that can be used to simulate the post-failure behaviour of landslides triggered by an earthquake.  相似文献   

Prediction of Seaward Slope Recession in Berm Breakwaters Using M5' Machine Learning Approach     

Alireza Sadat Hosseini  Mehdi Shafieefar 《海洋工程》2016,(1):19-32

In the design process of berm breakwaters, their front slope recession has an inevitable rule in large number of model tests, and this parameter being studied. This research draws its data from Moghim’s and Shekari’s experiment results. These experiments consist of two different 2D model tests in two wave flumes, in which the berm recession to different sea state and structural parameters have been studied. Irregular waves with a JONSWAP spectrum were used in both test series. A total of 412 test results were used to cover the impact of sea state conditions such as wave height, wave period, storm duration and water depth at the toe of the structure, and structural parameters such as berm elevation from still water level, berm width and stone diameter on berm recession parameters. In this paper, a new set of equations for berm recession is derived using the M5'' model tree as a machine learning approach. A comparison is made between the estimations by the new formula and the formulae recently given by other researchers to show the preference of new M5'' approach.  相似文献   

应用两次展开法求解系泊柱体慢漂运动方程     

金瑞佳  滕斌  吕林 《海洋工程》2016,34(5):11-19

在深海中系泊的海洋平台,如Spar平台,水下部分为带有系泊的圆柱结构,其水平方向运动响应往往具有较低的自振频率,容易在低频波浪力(源于非线性的差频效应)作用下发生共振响应,使结构发生大幅水平慢漂。当浮体的瞬时位置大幅偏离初始位置时,基于初始平衡位置的摄动展开法会存在较大误差。针对这一问题,采用两次展开方法,对大幅慢漂运动开展时域模拟研究。对双色波作用下自由漂浮圆柱的大幅运动响应问题进行数值分析,并与采用基于初始平衡位置的摄动展开法的计算结果进行了对比。结果表明,采用新的两次展开法可以计算出波浪遭遇频率的变化和波浪漂移阻尼,而这无法从基于初始平衡位置的常规摄动展开法中得到,体现了两次展开法在分析大幅慢漂问题上的优势。  相似文献   

脐带缆在潜器下放过程中的运动建模与仿真   总被引：1，自引：0，他引：1  

李霄霄  马宁  刘晗  顾解忡 《海洋工程》2016,34(2):47-55

潜器在下放布置过程中需要考虑变长度的脐带缆对其运动的影响,在考虑流的情况下,对脐带缆的有限差分模型进行了改进,并采用最小二乘方法求解由时间和空间上的中心差分格式离散后的非线性方程组。为了验证模型改进的有效性,将潜器在均匀定常流中水平匀速直航时的数值解与该特殊情况下的解析解进行比较,两组解的吻合不仅证实了模型改进的有效性,而且表明上述数值计算方法是可靠且有效的。在潜器下放布置运动给定的情况下,脐带缆的运动仿真结果表明,潜器姿态角的调整会对拖曳点处的缆绳张力大小和变化趋势产生显著的影响,流在改变缆绳空间形状的同时引起了缆绳对潜器作用力和力矩的非线性和时变性,脐带缆总是阻止潜器自身动力对运动速度和姿态角的改变,且对纵荡运动的影响最大。  相似文献   

Hybrid N-order Lagrangian Interpolation Eulerian?Lagrangian Method for Salinity Calculation     

吴炎成  朱首贤  周林  游小宝  张文静 《海洋工程》2016,(2):283-295

The Eulerian?Lagrangian method (ELM) has been used by many ocean models as the solution of the advection equation, but the numerical error caused by interpolation imposes restriction on its accuracy. In the present study, hybrid N-order Lagrangian interpolation ELM (LiELM) is put forward in which the N-order Lagrangian interpolation is used at first, then the lower order Lagrangian interpolation is applied in the points where the interpolation results are abnormally higher or lower. The calculation results of a step-shaped salinity advection model are analyzed, which show that higher order (N=3?8) LiELM can reduce the mean numerical error of salinity calculation, but the numerical oscillation error is still significant. Even number order LiELM makes larger numerical oscillation error than its adjacent odd number order LiELM. Hybrid N-order LiELM can remove numerical oscillation, and it significantly reduces the mean numerical error when N is even and the current is in fixed direction, while it makes less effect on mean numerical error when N is odd or the current direction changes periodically. Hybrid odd number order LiELM makes less mean numerical error than its adjacent even number order LiELM when the current is in the fixed direction, while the mean numerical error decreases as N increases when the current direction changes periodically, so odd number of N may be better for application. Among various types of Hybrid N-order LiELM, the scheme reducing N-order directly to 1st-order may be the optimal for synthetic selection of accuracy and computational efficiency.  相似文献   

Rotation Center and Horizontal Bearing Capacity of the Bucket Foundation in Soft Ground     

Xiaowei Tang  Xiwen Zhang  Qi Shao  Zhenqing Li 《Marine Georesources & Geotechnology》2016,34(6):594-601

In the last 20 years, the bucket foundation has been developed as a new type of offshore platform structure. Because of its short period of application to engineering practices, the theoretical decision on the rotation center and horizontal bearing capacity of the bucket foundation has yet to be agreed. A limit analysis method is used to determine the updated rotation center position and horizontal bearing capacity to evaluate the failure mechanisms of the bucket foundations. The results are compared with numerical simulation and experiments, and also with other theoretical methods. The proposed method can satisfactorily consider the engineering conditions and the result is accurate in determining the rotation center and horizontal bearing capacity.  相似文献   

Field Evaluation of the Vertical Bearing Capacity of a Screw Pretensioned Spun High-Strength Concrete Pile     

Yongkyu Choi  Dong-Chul Kim  Tae-Hyung Kim 《Marine Georesources & Geotechnology》2016,34(5):474-485

This study has evaluated the vertical bearing capacity by conducting static load tests for noise-free and vibration-free screw pretensioned spun high-strength concrete (PHC) piles installed using two different methods (end-squirting shoe and pre-boring methods). Vertical bearing capacity differences seem to occur due to the displacement of soils near the external circumference of a pile, depending on the installation method. A method by which to evaluate the bearing capacity of screw concrete piles is suggested by considering the equations that already have been used to calculate the bearing capacity of piles. Based on static load tests and analysis, the pile installed using the end-squirting shoe method was assumed to be a bored pile and it was reasonable to use the equation proposed by the Japanese Geotechnical Society. At the same time, the pile installed using the pre-boring method was deemed a low soil displacement pile and so it was reasonable to apply the equations proposed for calculating the bearing capacity of the driven pile suggested by the Architectural Institute of Japan.  相似文献   

Seismic Stability of Gravity Retaining Structures by Pseudo-Dynamic Method     

Rui Huang  Tang-Dai Xia 《Marine Georesources & Geotechnology》2016,34(1):1-9

An analytical expression of a gravity retaining wall's seismic stability against sliding and overturning is proposed in this article. The derivation, aiming at the cohesionless soil with inclined backfill surface and nonvertical wall back, is based on limit equilibrium analysis and the pseudo-dynamic method. The variations of the sliding and overturning stability safe factors with the horizontal seismic acceleration are investigated for different seismic amplification factors, soil friction angles, wall friction angles, vertical seismic acceleration coefficients, wall back inclination angles, and backfill surface inclination angles. The results indicate that the soil friction and horizontal seismic action significantly impact the seismic stability. The increase of vertical earthquake action changes the curvature of stability factor curves. The wall friction and back inclination strengthen the gravity retaining wall's resistance to sliding and overturning failure while the backfill surface inclination plays a negative role in the seismic stability. We also found that the seismic stability safe factors calculated by the proposed method are larger but more reasonable than those by the Mononobe-Okabe method.  相似文献