Retraction Note to: Adaptive neuro-fuzzy selection of the optimal parameters of protective spur dike

Natural Hazards - The Editors-in-Chief have retracted this article [1] because validity of the content of this article cannot be verified.     

Retraction Note to: Adaptive neuro-fuzzy prediction of the optimum parameters of protective spur dike

Natural Hazards - The Editors-in-Chief have retracted this article because validity of the content of this article cannot be verified.     

Consequences of dike breaches and dike overflow in a bifurcating river system

Currently, the effect of dike breaches on downstream discharge partitioning and flood risk is not addressed in flood safety assessments. In a bifurcating river system, a dike breach may cause overland flows which can change downstream flood risk and discharge partitioning. This study examines how dike breaches and overflow affect overland flow patterns and discharges of the rivers of the Rhine delta. For extreme discharges, an increase in flood risk along the river branch with the smallest discharge capacity was found, while flood risk along the other river branches was reduced. Therefore, dike breaches and resulting overland flow patterns must be included in flood safety assessments.

     

Adaptive neuro-fuzzy selection of the optimal parameters of protective spur dike

This study proposes a new approach for determining optimum dimensions of protective spur dike to mitigate scour amount around existing spur dikes. The main objective of this article was to predict the most optimum values of the protective spur dikes to reach the best performance. To predict the protective spur dike parameters for scour controlling around spur dikes, this paper constructed a process which selects the optimal protective spur dike parameters in regard to actual length of the protective spur dike, actual length of the main spur dikes, distance between the protective spur dike and the first spur dike, angle between protective spur dike and flow direction, flow intensity and median size of bed sediments with adaptive neuro-fuzzy (ANFIS) method. To build a protective spur dike with the best features, it is desirable to select and analyze factors that are truly relevant or the most influential to the spur dike. This procedure is typically called variable selection, and it corresponds to finding a subset of the full set of recorded variables that exhibits good predictive abilities. In this study, architecture for modeling complex systems in function approximation and regression was used, based on using ANFIS. Variable searching using the ANFIS network was performed to determine how the five factors affect the protective spur dike. Experimental model of the protective spur dike was used to generate training and checking data for the ANFIS network.     

Adaptive neuro-fuzzy prediction of the optimum parameters of protective spur dike

This study proposes a new approach for determining the optimum dimensions of a protective spur dike to mitigate the amount of scour around existing spur dikes. Several parameters of a protective spur dike were studied to determine their optimum values, including length, angle, and distance. Also the effect of changes of flow intensity and sediment size were examined. The main objective of this article was to predict the optimum values of protective spur dikes to attain the best performance. To predict the parameters of protective spur dikes for controlling the scour around spur dikes, we used the adaptive neuro-fuzzy inference system method to construct a process that simulates the optimal parameters of a protective spur dike, including the actual length of the protective spur dike, the actual length of the main spur dikes, the distance between the protective spur dike and the first spur dike, the angle between the protective spur dike and the direction of flow, the intensity of the flow, and median size of the bed sediments. This intelligent estimator was implemented using MATLAB/Simulink, and the performances were investigated. The simulation results presented in this paper show the effectiveness of the developed method.     

Chromiferous spinels of the elephant's head dike

Analysis by optical, X-ray diffraction and microprobe methods, of essentially unzoned, disseminated spinels within cumulus picrites and olivine gabbros reveals an unbroken range of compositions from aluminian chromite (34% Cr₂O₃) to chromian magnetite (4% Cr₂O₃). TiO₂ contents vary between 0.5 and 7.7%. Exsolution of ilmenite indicates originally higher TiO₂ contents. Quenched contact-facies rocks with abundant olivine phenocrysts contain strongly zoned spinels in which a titaniferous chromian magnetite rim (16% Cr₂O₃, 10% TiO₂) encloses cores of weakly titanian chromite (40% Cr₂O₃). Platy dendrites of exsolved spinel occur in abundance within cumulus olivines. The evidence suggests that crystallization of the disseminated spinels occurred under the influence of an increase in oxygen fugacity towards the interior of the intrusion, and that the compositional diversity has stemmed from the homogenization of originally zoned grains mantled to varying degrees by high-Ti, low-Cr rims.     

造山后脉岩组合与内生成矿作用

造山带大规模花岗质岩浆活动之后往往有一期区域性脉岩产出,被称为岩基后岩墙群。这类脉岩具有近同时形成、宽成分谱系和小体积的特点。根据太行山、燕山、东昆仑山、天山等造山带的观察,这类脉岩可以划分成煌斑岩质、玄武质、闪长质(安山质)、花岗闪长质(英安质)和花岗质(流纹质)等5组。前人大多偏重于研究其中基性部分,因而常常将其与大陆裂解相关基性岩墙群混为一谈。岩石地球化学分析表明,虽然同组脉岩不同样品之间可能存在演化关系,不同脉岩组之间很难相互演化。结合近年来有关岩浆过程速率的研究成果,推测这些脉岩是原生或近原生岩浆固结的产物。这意味着区域地温曲线在不同深度同时穿过所有相应原岩的固相线。基于岩浆起源热体制和区域岩石圈岩石学结构分析,笔者曾经指出,这样的岩浆产生条件要求造山带岩石圈拆沉作用。因此,这类岩墙群的形成是区域构造应力场由挤压向伸展转换阶段的产物,可以用来标定造山过程的结束,因而称其为造山后脉岩组合。进一步对比分析表明,这类脉岩组合分布非常普遍,是地球上业已发现的三类区域性岩墙群之一。尽管如此,基于热传递速率的分析,造山后脉岩组合的形成还应当伴随大规模流体活动。由于深部流体中成矿元素的浓度强烈依赖于压力,新的岩石成因模型意味着造山后脉岩组合与成矿作用相伴生。野外检验表明,可以基于露头观察识别成矿流体的通道和成矿元素大规模堆积的场所。因此,造山后脉岩组合不仅可以用来标定区域造山过程结束的时间,也是区域找矿预测的有效标志。     

Discussion of “Consequences of dike breaches and dike overflow in a bifurcating river system” by Anouk Bomers,Ralph M. J. Schielen and Suzanne J. M. H. Hulscher

In this discussion, the authors will point out that even if Bomers et al. (Nat Hazards 97:309–334, 2019) tackle an important problem, ignoring the uncertainties related to the roughness coefficients, Manning coefficients, the downstream boundary and most importantly the errors of the chosen software, HEC-RAS, are serious shortcomings of their study.

     

Fragility curves in operational dike reliability assessment

Operational flood prediction and flood risk assessment have become important components of flood management. One main aspect is the reliability assessment of the flood defence line during a flood event. This is generally performed by a comparison of the water level in the river to the crest height of the dikes whilst taking only hydraulic and geometric aspects into account. Additional information about material zones and material parameters are often available. However, these data are not in an appropriate shape when deriving the reliability of the flood defence line. This paper outlines how the fragility curve of a dike section is used to appropriately integrate geostatic and geohydraulic dike characteristics into operational flood management systems. Fragility curves are the result of a model-based reliability analysis and they summarise the dike performance depending on the water level. Failure modes such as piping or slope failure are included. In a case study, fragility curves for dike sections along the River Emscher (Germany) are determined. Their practical implementation in an operational flood management system shows an improvement in the operational reliability assessment due to the additional information taken into account. The use of fragility curves also supports the decision-making processes when emergency flood protection measures are required.     

柳州市静兰防洪堤工程岩溶发育特征及渗漏评价

本文论述了柳州市静兰防洪堤工程区岩溶发育特征、规律,阐明了西江船厂区地下河系、溶洞、落水洞、漏斗、洼地等的发育规模、连通性,并进行岩溶渗漏评价。结果表明采取围井、填埋等措施后,渗漏量只有0 55×104m3 d,能有效地防止岩溶水的倒灌。     

土工织物加固堤防非线性有限元分析

在进行堤防加筋设计时,土工织物的强度,加筋的长度,加筋的位置,加筋的层数等因素都是应该考虑的。利用欧洲通用的岩土工程有限元软件Plaxis,采用强度参数降低法,对某一堤防加筋的效果、机理作了分析。指出无论在任何位置加筋,土工织物都有一个最小长度。最小长度的确定,要具体问题具体分析。确定了加筋的最佳位置,并建议加两层,一层在底部,一层在中部,以抑制最危险滑弧的发展,提高整体稳定性,减少堤防变形发展。     

造山后脉岩组合的岩石成因——对岩石圈拆沉作用的约束

造山后脉岩组合是在寄主岩基冷却之后形成的，可能是造山带应力场转换的标志。昆仑造山带早中生代末期以及太行山-燕山造山带晚中生代花岗质岩基中广泛出露这种类型的脉岩，可划分为煌斑岩质，玄武质，闪长质，花岗闪长质．花岗质和富硅花岗质等5组。主元素和痕量元素分析表明它们是不同的原生岩浆固结的产物，相互之间不存在重要的分离结晶，同化混染和岩浆混合作用的关系，因而要求软流圈／岩石圈系统不同圈层的源区岩石同时达到部分熔融的条件。结合已有的高温高压实验，区域岩石圈结构和地质事件序列的分析，认为岩石圈拆沉作用是造山后脉岩组合形成的最合理触发机制。简单热模拟表明，软流圈窗顶界埋深达到一定深度时（例如昆仑造山带为82km），可以满足处于不同深度位置的中性麻粒岩，基性榴辉岩和地幔橄榄岩同时发生部分熔融。这时，岩石圈／软流圈系统可以有6～8个产生岩浆的位置。热的软流圈物质快速涌入软流圈窗，不仅触发地幔岩的减压熔融，也可能导致区域构造应力场由挤压转换为伸展，为岩浆的快速侵位创造了条件。所提供的岩石成因模型可以更合理地解释造山后脉岩组合的地质特征，主元素和痕量元素特征，也可以满足同位素体系变异所要求的条件。     

可变网格下的堤防溃口展宽二维数学模型

传统固定结构的计算网格不适于处理计算边界动态变化的问题,利用动网格技术,结合土力学中粘性土河岸的崩塌机理,建立了可变网格下的堤防溃口展宽二维数学模型,在对模型进行验证对比的基础上,对北江下游的大塘围蓄滞洪区口门处的崩塌展宽过程进行了模拟,模型计算结果表明:随着溃堤水流对堤防土体的冲蚀,堤防发生崩塌破坏,溃口洪水流量迅速增大,与实际相符,说明通过采用可变网格与土力学中粘性土河岸崩塌机理相结合的计算方法,使得模型具备准确模拟蓄滞洪区口门处横向崩塌展宽过程的优点。     

Probabilistic flood risk analysis considering morphological dynamics and dike failure

A comprehensive flood risk assessment should aim not only at quantifying uncertainties but also the variability of risk over time. In this study, an efficient modelling framework was proposed to perform probabilistic hazard and risk analysis in dike-protected river systems accounting for morphological variability and uncertainty. The modelling framework combined the use of: (1) continuous synthetic discharge forcing, (2) a stochastic dike breach model dynamically coupled to a stochastic unsteady one-dimensional hydraulic model (MIKE1D) describing river flows, (3) a catalogue of pre-run probabilistic inundation maps (MIKE SHE) and (4) a damage and loss model (CAPRA). The methodology was applied using continuous simulations to a 45-km reach of the Upper Koshi River, Nepal, to investigate the changes in breach and flood hazards and subsequent risks after 2 and 5 years of probable river bed aggradation. The study results indicated an increase in annual average loss of 4% per year driven by changes in loss distribution in the most frequent loss return periods (20–500 years). The use of continuous simulations and dike breach model also provided a more robust estimation of risk metrics as compared to traditional binary treatment of flood defence and/or the direct association of flow with loss return periods. The results were helpful to illustrate the potential impacts of dynamic river morphology, dike failure and continuous simulation and their significance when devising flood risk study methodologies.     

海堤加筋的分析测试与材料选用

人们对土工合成材料加筋在海堤软基处理中的作用与材料选用尚存在明显意见分歧,从而限制了它恰当地应用。通过某一工程实例,数值分析了筋材在包括极限稳定等各种工况下的受力性状及对提高海堤抗滑稳定性的贡献。利用改装后的位移计,对土工格栅应变进行了原位测试。根据数值分析和原位测试成果,探讨了海堤筋材的选用及其设计参数的选取,得到了海堤筋材应首选单向拉伸土工格栅、选用时应同时规定极限延伸率上下限等一些有益的结论     

丁坝回流分区机理及回流尺度流量试验研究

通过三维激光颗粒动态分析仪(3D-PDA)对玻璃水槽内丁坝回流区的流速进行测量,获得了回流区流速分布的详细资料。根据流量连续原理和回流区流速分布,对丁坝回流区进行了区域划分:沿横向划分为负流速区、正流速区和主流区;沿纵向分为回流减流区和回流增流区。在此基础上进一步研究了回流尺度和回流流量沿纵向的变化规律。结果表明,回流区正负流区流量沿纵向呈纺锤形分布,负流速区和回流区的宽度在纵向基本呈线性变化。     

Geochemical and petrological aspects of dike intrusions in the Lycian ophiolites (SW Turkey): a case study for the dike emplacement along the Tauride Belt Ophiolites

Lycian ophiolites located in the Western Taurides, are cut at all structural levels by dolerite and gabbro dikes. The dolerite dikes from this area are both pristine and metamorphosed. The non-metamorphosed dikes are observed both in the peridotites and in the metamorphic sole rocks. Accordingly, the non-metamorphosed dikes cutting the metamorphic sole were generated after cooling of the metamorphic sole rocks. The metamorphosed dolerite dikes are only observed in the peridotites. The physical conditions and timing of the metamorphism for the metamorphosed dolerite dikes are similar to those of the metamorphic sole rocks of the Lycian ophiolites suggesting that the metamorphosed dolerite dikes were metamorphosed together with the metamorphic sole rocks. Therefore, the dike injections in the western part of the Tauride Belt Ophiolites occurred before and after the generation of the metamorphic sole rocks. All metamorphosed and non-metamorphosed dikes are considered to have the same origin and all of them are subduction-related as inferred from whole-rock geochemistry and lead isotopes. Lead isotope compositions of whole rocks of both dike groups cluster in a narrow field in conventional Pb isotope diagrams (²⁰⁶Pb/²⁰⁴Pb = 18.40–18.64; ²⁰⁷Pb/²⁰⁴Pb = 15.56–15.58; ²⁰⁸Pb/²⁰⁴Pb = 38.23–38.56) indicating a derivation from an isotopically homogeneous source. On the ²⁰⁷Pb/²⁰⁴Pb versus ²⁰⁶Pb/²⁰⁴Pb diagram, isotope compositions of the dikes plot slightly below the orogen curve suggesting contributions from mantle reservoir enriched by subducted oceanic lithosphere. Such a signature is typical of island arc magmatic rocks and supports the formation of the investigated rocks in a subduction-related environment.