Applied Mechanics and Materials Vols. 501-504

Abstract: After impoundment of the Three Gorges Reservoir, Jingjiang reach, in the middle of the Yangtze River, has gradually shown a series of atypical fluvial features, adversely affecting the maintenance of waterways. Citing the Laijiapu Waterway, a meandering segment in the lower Jingjiang for example, this paper compared the fluvial features of the channel before and after the impoundment, summed up its navigation-obstructing features, and proposed guarding the point bar on the convex bank and channel bar in the widening section as a key to maintaining the stability of the navigation channels.

Abstract: The mathematical model of optimal daily operation for multiple pump units with adjustable-blade in single pumping station was solved by means of decomposition-dynamic programming aggregation method and experimental optimization method while the peak-valley electricity price was taken into consideration. After taking No.4 Huaian Pumping Station as a study case, a series of optimal operation schemes under different average daily heads and water pumping loads were obtained. Based on the analysis of optimization benefits, the applicability comparison of two optimal algorithms have been carried out, by which the application scope of each algorithm was proposed.

Abstract: The power of a test is the probability that it cannot reject a null hypothesis when it is true. With interchangeably of non-parametric Mann-Kendall test, practical application is used in meteorological elements analysis. In this study, trend detection of meteorological elements data of Shapingba district in Chongqing, during 1951 to 2011, was estimated by non-parametric Mann-Kendall test. The analyzed elements are composed by mean precipitation, annual sunshine hours, annual humidity, annual mean temperature and annual mean wind speed. And the results show that inter-annual variations of precipitation and mean annual relative humidity are not significant. However, inter-annual variation of sunshine duration is significantly reduced, while inter-annual temperature and wind speed are significantly increased. At the same time, the non-parametric Mann-Kendall test also detects the trend on seasonal data. It is different from the annual data, and trends in different seasons show markedly different.

Abstract: Blasting model of ice is established by ANSYS-LSDYNA in this paper. By using LS-PREPOST, the author analyzes the broken volume or diameter of ice in different working conditions, including the buried depth of explosive, the load and the thickness of ice. ORIGN drawing software is used to analyze the most suitable blasting location with different thickness of ice. The result shows that when the thickness is between 20cm and 60cm, the best blasting coefficient of water-medium ice is K=R/ H =0.5~1. It also shows that the explosive effect will be better when it is exploded under ice layer than in the middle or at the surface of ice layer. Calculation result and field test align fairly well. By simulating blasting parameter in different working conditions, ice prevention database is built, providing references for designers to develop a series of shaped into ice equipments. It also has important practical meaning to use various equipments to prevent and treat ice disasters of the Yellow River.

Abstract: In this work, bibliometric analysis was applied to evaluate global scientific production and developing trend of the dam safety monitoring research through Science Citation Index (SCI) papers with online version published as following aspects: publication outputs, subject categories, countries, institutes, citations, authorship and co-authorship, author key words and co-words analysis. Global literature of the dam safety monitoring research has increased rapidly over the past years and has boosted in recent years. The quantity and quality of papers in P.R. China are in a leading position. There is a very important new finding from the research focus that tailings dam has been adequately studied. With the further development of the dam safety monitoring research, it is presumed that scientists might concentrate mainly on safety prediction and health monitoring instead of simple safety monitoring.

Abstract: In order to grasp the effects of maritime management accurately and improve the maritime control level in complex waters, we should evaluate the performance in maritime sectors. Directing at maritime control problems in complex waters and combining with functions of maritime sectors, this paper established a performance evaluation index system of maritime control in inland complex waters. Based on the cloud model, a synthetic evaluation method is proposed to maritime control performance in inland complex waters. Through analyzing the survey data in Jingzhou River Bridge waters, the result shows that the evaluation model is scientific and feasible. The evaluation method provides a reference for improving the maritime control performance in inland complex waters.

Abstract: China is a water resource-poor country, in recent years, rapid population growth resulting in water issues have become increasingly prominent. Taking Anhui Province as an example, using fuzzy synthetic evaluation method and combining the analytic hierarchy process evaluation analysis of water resources carrying capacity. Firstly, establishing the evaluation criteria of the index system of regional water resources carrying capacity and individual indicators, calculating evaluation index weight,establishing the weight fuzzy matrix, using Vague set and analytic hierarchy process method to determine the weight vector.Secondly, compositing a fuzzy matrix of weight values after obtaining the value of the weights of the various indicators, calculating the degree of membership, establishing the fuzzy relation matrix, fuzzy subset into a comprehensive evaluation model, and seeking the comprehensive evaluation value .Finally, determining the level of sustainable use of water resources in the specific area based on the principle of maximum degree of membership . After the evaluation are analyzed and compared in order to elaborate the evaluation method is feasible and effective.

Abstract: Considering topographic and geologic conditions, project layout and investments, concret arch dam is adopted in a hydropower plant and underground powerhouses are arranged in mountains on left and right banks. However, the minimum distance between the excavation boundary of abutment of arch dam on elevation 850m and underground powerhouse is only 110m. Abutment load created by reservoir storage, permeability and earthquake may affect general stability of underground caverns in operation period. Thus, using elasto-plastic finite difference method, three dimensional numerical simulation models of underground caverns and slope of abutment of arch dam is establised and proposed key issues are systemly studied. The calculation results show that, under reservoir storage and dam vibration subject to earthquke, abutment load has small effect on plastic zone, displacement and stress around opennings and the caverns would be stable in operation period.

Abstract: The global estuarial studies have focused on water and sediment flux into the sea and the effect of human activities on the evolution of estuarial water and sediment. In the present study, we elaborated the impact of human activities on the water-sediment relation based on the water and sediment features at Datong Station (1951-2008). The results showed that the annual runoff of several years was slightly increased in 1990s in Yangtze River (Yangtze) River estuary. The changes were not obvious in these years. The suspended sediment flux (SSF) showed a phased downward trend, which was associated with water storage of the Three Gorges reservoir, the middle-and down-stream river-lake relationship, artificial sand excavation and water drinking and regulation. The ratio average of suspended sediment less than 0.01mm and 0.05mm was increased from 1987 to 2002 than the value before 1986. The value reached the maximal in 2003, and afterwards the sediment flux ratio of these two particle sizes was decreased. After 1986, the total SSF was reduced. The SSF less than 0.01mm showed a wavy decline along with the increase of suspended sediment ratio, while the SSF less than 0.05mm was decreased along with the reduction of the total suspended sediment flux. Meanwhile, the average of median suspended sediment particle size was 0.027mm before 1986 and was 0.0094mm from 1987 to 2008. The inflexion point appearing in 1986 was consistent with the inflexion point of SSF reduction. It was directly related to water storage of the Gezhouba Dam. The median particle diameter of riverbed sand had an increase of 0.01mm/10a in average after 1977. The maximal particle diameter of riverbed sand had changed little. Both suspended sediment and bed sand became fine along the estuary and slightly became coarse in the mouth, indicating that it was functioned as the estuarial filter. The above observations would provide valuable insights for science and objective evaluation of the effect of human activities on an estuary.

Abstract: It could be seen from the past, process of the promoting progress of human society's tends to demanding for energy.With the advancement of technology development as time goes on, countries spare no effort to develop new energy sources, while also continue digging traditional industrial energy. Since the 1960`s, people in the field of shale gas exploitation has made substantial progress. For the development of new energy storage proposed higher requirements, in order to meet growing energy needs, for geotechnical engineering particularity, from the numerical simulation of hydraulic fracturing start by comparing different stress crack formation in case of carry case, at the conclusion on the basis of experimental results can be applied to specific projects put forward the basic assumptions.