Search | Engineering

订阅投稿

首页工程期刊工程焦点工程成就工程前沿关于我们 English

资源类型

期刊论文 24

年份

2022 2

2021 1

2020 1

2019 1

2017 3

2016 1

2015 2

2014 1

2013 1

2012 1

2011 2

2010 1

2009 1

2008 1

2006 1

2003 1

2002 1

2001 1

2000 1

展开︾

关键词

冲刷 2

三峡工程 1

冲刷坑 1

冲蚀 1

判据 1

劣化分析 1

动床模型 1

同步波动 1

多波束测深数据 1

安全保障 1

崩岸 1

弹性涂层 1

弹性边壁 1

形态要素 1

微观特性 1

抗汽蚀 1

抗磨蚀 1

数学模型 1

水下陡坎 1

展开︾

检索范围：

排序：展示方式：

3D finite element method (FEM) simulation of groundwater flow during backward erosion piping

Kristine VANDENBOER,Vera van BEEK,Adam BEZUIJEN

《结构与土木工程前沿（英文）》 2014年第8卷第2期页码 160-166 doi: 10.1007/s11709-014-0257-7

摘要： Backward erosion piping is an important failure mechanism for cohesive water retaining structures which are founded on a sandy aquifer. At present, the prediction models for safety assessment are often based on 2D assumptions. In this work, a 3D numerical approach of the groundwater flow leading to the erosion mechanism of backward erosion piping is presented and discussed. Comparison of the 2D and 3D numerical results explicitly demonstrates the inherent 3D nature of the piping phenomenon. In addition, the influence of the seepage length is investigated and discussed for both piping initiation and piping progression. The results clearly indicate the superiority of the presented 3D numerical model compared to the established 2D approach. Moreover, the 3D numerical results enable a better understanding of the complex physical mechanism involved in backward erosion piping and thus can lead to a significant improvement in the safety assessment of water retaining structures.

关键词： backward erosion piping groundwater flow 3D finite element method (FEM)

HTML PDF 收藏

Analysis of flow over backward facing step with transition

Dwarikanath RATHA,Arindam SARKAR

《结构与土木工程前沿（英文）》 2015年第9卷第1期页码 71-81 doi: 10.1007/s11709-014-0270-x

摘要： The present study deals with the study of the velocity distribution and the separation phenomenon of flow of air over a two dimensional backward facing step. The flow of air over a backward facing step has been investigated numerically using FLUENT. Flow simulation has been carried out in a backward facing step having an expansion ratio (ratio of the height before and after the step) of 1:1.94 and the results obtained are compared with the published experimental results. Comparison of flow characteristics between steps with three different transitions is made. The variation of reattachment length for all the three cases are analyzed for wide range of Reynolds number ranging from 100 to 7000 which covers the laminar, transition and turbulent flow of air. Simulation of the flow over steps with expansion ratios of 1:1.24, 1:1.38, 1:1.47, 1:1.53, 1:1.94, 1:2.20 are also carried out to examine the effect of different expansion ratios on the reattachment length. It is found that the primary reattachment length increases with increase in the expansion ratio. The primary reattachment length at the bottom wall downstream of the step is minimum for the step with round edged transition and maximum for the step with a vertical drop transition.

关键词： Reattachment length backward facing step transition flow separation k-? model

HTML PDF 收藏

Embankment dam foundation analysis for the decrease of internal erosion likelihood

Marc SMITH

《结构与土木工程前沿（英文）》 2012年第6卷第4期页码 431-436 doi: 10.1007/s11709-012-0183-5

摘要： A zoned embankment dam is founded on clay underlain by a sand deposit. Major seepage phenomena were noticed in the foundation downstream from the dam where the vertical seepage forces in the sand layer were expected to exceed the downward forces due to the overlying clay. Modern technologies were applied to delineate critical zones to help design optimal rehabilitation measures. A global electromagnetic survey was carried out to detect and map the main sources, pathways and exits of seepage. Based on these global findings, a more detailed analysis was then conducted to identify zones where thickness of the foundation clay is minimal, pore pressures in sand are higher and thus where the factor of safety against uplift is lower and internal erosion is more likely to occur. Clay thickness evaluation required the determination of land surface as well as clay-sand contact elevations. A laser airborne survey was performed to model the land surface elevation. Data concerning the clay-sand contact elevation came from the interpreted stratigraphy based on a series of boreholes and cone penetration tests. This data was combined in a geostatistical model along with the measured piezometric levels in the foundation. This resulted in a contour map showing factors of safety against uplift over the entire downstream area. The use of modern technologies, namely electromagnetic and laser surveys as well as geostatistical tools, was instrumental in defining the limits of an otherwise spread-out problem and to provide an optimal solution, in terms of costs and effectiveness, for the long-term stabilization of the foundation.

关键词： seepage detection geostatistical analysis dam monitoring internal erosion LIDAR survey

HTML PDF 收藏

conservation in China’s coal-fired power industry by installing advanced units and organized phasing out backward

Weiliang WANG, Junfu LYU, Zheng LI, Hai ZHANG, Guangxi YUE, Weidou NI

《能源前沿（英文）》 2019年第13卷第4期页码 798-807 doi: 10.1007/s11708-019-0633-z

摘要： Coal-fired power is the main power source and the biggest contributor to energy conservation in the past several decades in China. It is generally believed that advanced technology should be counted on for energy conservation. However, a review of the decline in the national average net coal consumption rate (NCCR) of China’s coal-fired power industry along with its development over the past few decades indicates that the up-gradation of the national unit capacity structure (including installing advanced production and phasing out backward production) plays a more important role. A quantitative study on the effect of the unit capacity structure up-gradation on the decline in the national average NCCR suggests that phasing out backward production is the leading factor for the decline in the NCCR in the past decade, followed by the new installation, whose sum contributes to approximately 80% of the decline in the national average NCCR. The new installation has an effective affecting period of about 8 years, during which it would gradually decline from a relatively high value. Since the effect of phasing out backward production may remain at a certain degree given a continual action of phasing out backward capacity, it is suggested that the organized action of phasing out backward production should be insisted on.

关键词： coal-fired power energy conservation net coal consumption rate new installation phasing out backward production unit capacity structure

HTML PDF 收藏

抗磨蚀材料失效过程的微观特性

王飚,王宇栋,张自华,何筱奎,诸小丽

《中国工程科学》 2001年第3卷第8期页码 82-86

摘要：

用光学显微镜、扫描电镜、电子探针和X射线衍射，对抗汽蚀较优的硼不锈钢堆焊层和抗磨蚀较优的碳化钨陶瓷堆焊层的原样、汽蚀后样和磨蚀后样进行了微观分析研究。结果表明，硼不锈钢堆焊层是较好的抗汽蚀材料，但抗磨蚀效果不理想；碳化钨对磨蚀损坏有良好的屏障作用；磨蚀坑是气泡溃灭产生的脉冲式法向负压力和脉冲式泥沙冲击切向分力联合作用的结果。

关键词：抗汽蚀抗磨蚀微观特性

HTML PDF 收藏

Effect of land use and land cover change on soil erosion and the spatio-temporal variation in Liupan

Bin QUAN, M. J. M. R?MKENS, Rui LI, Fang WANG, Jie CHEN

《环境科学与工程前沿（英文）》 2011年第5卷第4期页码 564-572 doi: 10.1007/s11783-011-0348-9

摘要： The Liupan Mountains are located in the southern Ningxia Hui Autonomous Region of China, that forms an important divide between landforms and bio-geographic regions. The populated part of the Liupan Mountain Region has suffered tremendous ecological damage over time due to population pressure, excessive demand and inappropriate use of agricultural land resources. To present the relationship between land use/cover change and spatio-temporal variation of soil erosion, data sets of land use between the late 1980s and 2000 were obtained from Landsat Thematic Mapper (TM) imagery, and spatial models were used to characterize landscape and soil erosion conditions. Also, soil erosion in response to land use and land cover change were quantified and analyzed using data from geographical information systems and remote sensing. Soil erosion by water was the dominant mode of soil loss, while soil erosion by wind was only present on a relatively small area. The degree of soil erosion was classified into five severity classes: slight, light, moderate, severe, and very severe. Soil erosion in the Liupan Mountain Region increased between the late 1980s and 2000, both in terms of acreage and severity. Moderate, severe, and very severe eroded areas accounted for 54.86% of the total land area. The lightly eroded area decreased, while the moderately eroded area increased by 368817 ha (22%) followed by severe erosion with 146552 ha (8.8%), and very severe erosion by 97067.6 ha (5.8%). Soil loss on sloping cropland increased with slope gradients. About 90% of the cropland was located on slopes less than 15°. Most of the increase in soil erosion on cropland was due to conversion of steep slopes to cropland and degradation of grassland and increased activities. Soil erosion was severe on grassland with a moderate or low grass cover and on dry land. Human activities, cultivation on steep slopes, and overgrazing of pastures were the main reasons for the increase in erosion severity.

关键词： land use/land cover change soil erosion geographical information system remote sensing Liupan Mountain Region

HTML PDF 收藏

水轮机抗磨蚀金属材料的优化设计

王飚,张自华,王宇栋

《中国工程科学》 2000年第2卷第2期页码 64-67

摘要：

对抗磨蚀金属材料的基础研究表明，在10种常用结构材料的金属中，以钨、钴、铬的抗气蚀性最佳；生产应用研究结果表明，钨系材料中的火焰喷焊WC-M硬面陶瓷材料，铬系材料中的电镀稀土铬硬面材料，钴系材料中的等离子喷焊CoCrWC硬面材料，都是抗磨蚀性能较优，成本较低，并可进入工业应用的水轮机抗磨蚀结构材料。

关键词：水轮机磨蚀材料设计

HTML PDF 收藏

水机材料的抗磨蚀性判据研究

王飚,王宇栋,张自华,叶献国

《中国工程科学》 2003年第5卷第7期页码 58-61

摘要：

为了证实水机材料的抗磨蚀和抗空蚀性能与材料的常规宏观性能之间的相依关系，选取4种具代表性的材料（碳化钨涂层、NiCr合金涂层、硼不锈钢涂层和钛），进行空蚀和磨蚀试验，并测试了它们的硬度和抗腐蚀性。试验结果表明，材料的空蚀和磨蚀抗力与硬度和抗腐蚀性有着紧密的相依关系：高硬度是抗磨蚀性优的第一判据，较强的抗腐蚀性是第二判据；高抗腐蚀性是抗空蚀性优的第一判据，较高的硬度是第二判据。

关键词：水机材料磨蚀判据

HTML PDF 收藏

Effects of alfalfa coverage on runoff, erosion and hydraulic characteristics of overland flow on loess

Shufang WU, Pute WU, Hao FENG, G. P. Merkley

《环境科学与工程前沿（英文）》 2011年第5卷第1期页码 76-83 doi: 10.1007/s11783-011-0282-x

摘要： An evaluation of the interactions between vegetation, overland and soil erosion can provide valuable insight for the conservation of soil and water. An experiment was conducted to study water infiltration, runoff generation process, rate of sediment erosion, and hydrodynamic characteristics of overland flow from a sloping hillside with different draw-off discharges from alfalfa and control plots with 20° slope. The effect of alfalfa on runoff and sediment transport reduction was quantitatively analyzed. Alfalfa was discussed for its ability to reduce the overland flow scouring force or change the runoff movement. Compared to the bare-soil plots, alfalfa plots generated a 1.77 times increase in infiltration rate. Furthermore, the down-slope water infiltration rate for the bare soil plots was higher than in the up-slope, while the opposite was found in the alfalfa plots. In addition, alfalfa had a significant effect on runoff and sediment yield. In comparison to the control, the runoff coefficient and sediment transportation rate decreased by 28.3% and 78.4% in the grass slope, respectively. The runoff generated from the alfalfa and bare-soil plots had similar trends with an initial increase and subsequent leveling to a steady-state rate. The transport of sediment reduced with time as a consequence of the depletion of loose surface materials. The maximum sediment concentration was recorded within the first few minutes of each event. The alfalfa plots had subcritical flow while the bare-soil plots had supercritical flow, which indicate that the capability of the alfalfa slope for resisting soil erosion and sediment movement was greater than for bare soil plots. Moreover, the flow resistance coefficient and roughness coefficient for the alfalfa plots were both higher than for the bare-soil plots, which indicate that overland flow in alfalfa plots had retarded and was blocked, and the flow energy along the runoff path had gradually dissipated. Finally, the ability to erode and transport sediment had decreased.

关键词： alfalfa soil erosion runoff and sedimentation soil water infiltration overland flow hydrodynamic characteristics

HTML PDF 收藏

The cavitation erosion damage process of dynamically loaded journal bearings

MA Yan-yan, CHENG Xian-hua

《机械工程前沿（英文）》 2006年第1卷第4期页码 461-464 doi: 10.1007/s11465-006-0059-2

摘要： The cavitation damage model was built using finite element analysis software MSC.Marc. This paper attempted to numerically analyze the action process based on damage mechanics when a jet created by bubble collapse acted on the bearing surface in the process of cavitation erosion. The numerical results show that the values of equivalent plastic strain and void volume fraction increase with time. The values of damage scalar are higher on the bearing surface and subsurface, and decrease when it approaches the interface of overlay and nickel layer. The strain history and damage evolvement of bearing material acted on by jet impact load can be calculated efficiently using the proposed method, which develops a new method of analyzing cavitation erosion failure of the bearing surface.

关键词： bearing fraction increase collapse process evolvement

HTML PDF 收藏

格上后向无关联性安全的验证者本地撤销群签名 Research Articles

张彦华1,刘西蒙2,胡予濮3,甘勇4,贾惠文5

《信息与电子工程前沿（英文）》 2022年第23卷第6期页码 876-892 doi: 10.1631/FITEE.2000507

摘要：

群成员可撤销的群签名中，验证者本地撤销机制似乎是一种更为灵活的选择，因为在签名验证过程中，仅需验证者获取最新的撤销信息，而不涉及签名者。与经典的数论型构造相对应，Langlois等人给出了后量子安全的首个格上验证者本地撤销群签名。然而，截至目前，所有格上验证者本地撤销群签名方案暂不满足后向无关联性，该特性可保障群成员被撤销前其对消息签名的匿名性和无关联性。本文给出了首个格上后向无关联性安全的验证者本地撤销群签名方案，从而解决了这一公开问题。新方案为群公钥和群成员签名密钥节省了O(log N)的比特大小，并且没有任何公钥加密。特别地，新方案在随机谕言机模型下是可证明安全的，其困难性可归约至两个经典格上难题假设，即小整数解难题和差错学习难题。

关键词：群签名；格密码；验证者本地撤销；后向无关联性；小整数解难题

HTML PDF 收藏

长江干流水下岸坡侵蚀自动识别 Article

颜阁, 程和琴, 姜泽宇, 滕立志, 唐明, 石天, 姜月华, 杨国强, 周权平

《工程（英文）》 2022年第19卷第12期页码 50-61 doi: 10.1016/j.eng.2021.03.027

摘要：

识别河岸侵蚀的风险是确保早期预警和预防或控制包括长江在内的河流集水区崩岸的一项重要挑战。本文引入一种基于地貌要素的算法，通过调整多波束回波探测数据的平坦度来提取河岸侵蚀信息。该算法绘制了10 个水下地貌形态要素，包括坡、坡脚、水平面、脊、顶、谷、凹陷、凸起、坑和坡肩。利用21 个平坦度值构建水下河岸侵蚀特征的识别策略。结果表明：当平坦度为10°时，作为侵蚀载体的岸坡陡坎被坡要素覆盖。平坦度为0°时，冲刷坑和河岸破损由河岸附近的坑要素和岸坡中的凹陷表示。河道水下沙波是加速河岸侵蚀的重要因素，尤其是靠近河岸坡脚的沙波；沙波的临界平坦度为3°。分析了水下地貌形
态要素的分布，并用于绘制河岸侵蚀库存图。分析结果表明，近岸区水深较大，易形成较大的冲刷坑和较长的河岸陡坎。窝崩往往发生在较长的岸坡处，以缩短其长度。经讨论陆地、海洋和河流环境中平坦度值的不同设置，得出的结论是，多样化的平坦度值能够显著识别河流水下地貌形态。因此，本研究为基于平坦度的河流水下地貌形态要素识别提供参考，增强了从大量多波束测深数据定位水下岸坡失稳迹象与风险的能力。

关键词：多波束测深数据形态要素河岸侵蚀水下陡坎冲刷坑崩岸

HTML PDF 收藏

Branch-pipe-routing approach for ships using improved genetic algorithm

Haiteng SUI,Wentie NIU

《机械工程前沿（英文）》 2016年第11卷第3期页码 316-323 doi: 10.1007/s11465-016-0384-z

摘要：

Branch-pipe routing plays fundamental and critical roles in ship-pipe design. The branch-pipe-routing problem is a complex combinatorial optimization problem and is thus difficult to solve when depending only on human experts. A modified genetic-algorithm-based approach is proposed in this paper to solve this problem. The simplified layout space is first divided into three-dimensional (3D) grids to build its mathematical model. Branch pipes in layout space are regarded as a combination of several two-point pipes, and the pipe route between two connection points is generated using an improved maze algorithm. The coding of branch pipes is then defined, and the genetic operators are devised, especially the complete crossover strategy that greatly accelerates the convergence speed. Finally, simulation tests demonstrate the performance of proposed method.

关键词： branch pipe ship industry piping system optimization algorithm

HTML PDF 收藏

Geosynthetics used to stabilize vegetated surfaces for environmental sustainability in civil engineering

Jie HAN,Jun GUO

《结构与土木工程前沿（英文）》 2017年第11卷第1期页码 56-65 doi: 10.1007/s11709-016-0380-8

摘要： Geosynthetics, factory-manufactured polymer materials, have been successfully used to solve many geotechnical problems in civil engineering. Two common applications are earth stabilization and erosion control. Geosynthetics used for earth stabilization include but are not limited to stabilized slopes, walls, embankments, and roads. Geosynthetics used for erosion control are mostly related to slopes, river channels and banks, and pond spillways. To enhance environmental sustainability, vegetation has been increasingly planted on the facing or surfaces of these earth structures. Under such a condition, geosynthetics mainly function as surficial soil stabilization while vegetation provides green appearance and erosion protection of earth surfaces. Recently, geosynthetic or geosynthetic-like material has been used to form green walls outside or inside buildings to enhance sustainability. Geosynthetics and vegetation are often integrated to provide combined benefits. The interaction between geosynthetics and vegetation is important for the sustainability of the earth and building wall surfaces. This paper provides a review of the current practice and research in the geosynthetic stabilization of vegetated earth and building surfaces for environmental sustainability in civil engineering with the emphases on geosynthetic used for erosion protection, geosynthetic-stabilized slopes, geosynthetic-stabilized unpaved shoulders and parking lots, and geosynthetic-stabilized vegetated building surfaces.

关键词： erosion geosynthetic stabilization sustainability vegetation