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Feng Z.-J.,Changan University | Wang H.,Shaanxi Expressway Construction Group Company | Wei J.,Changan University | Gao X.,ZhongJiaoTongli Construction Co. | And 2 more authors.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2015

In order to ascertain the effect of loess gulch on the bearing capacity of bridge pile foundation, for the first time, based on the self-developed platform model test, the model tests can fully reflect the characteristics and work performance of pile foundation in loess gulch area. The change rules of vertical bearing capacity, pile axial force and lateral friction force of the pile foundation with different slopes and pile lengths are analyzed, and some engineering technical advices are given based on test results. The results show that: (1) With the increase of slope, the bearing capacity of piles with the same pile length decreases, the influence degree of bearing capacity increases gradually, and the range varies from 7% to 35%. (2) The pile bearing capacity increases with the increase of pile length to some extent; when the pile length increases to a certain length, the rate of increase becomes slow. (3) The effective pile length with the same buried depth decreases with the increase of slope. (4) The design of bridge pile foundation should fully consider the engineering technology of preventing the soil around piles being eroded in the loess gulch area. © 2015, Editorial Office of Chinese Journal of Geotechnical Engineering. All right reserved.

Zhang Z.,Xian University of Technology | Zhao Y.,Xian University of Technology | Zhao Y.,Xibei Engineering Corporation Ltd | Jia B.,Xian University of Technology | Fu M.,Xian University of Technology
Yingyong Lixue Xuebao/Chinese Journal of Applied Mechanics | Year: 2015

According to the experimental results of velocity distribution and wall resistance by Rajaranam et al., velocity distribution in hydraulic jump region, change law of maximum velocity distribution are analyzed, variation law of thickness of hydraulic jump jet in main section, wall shear stress coefficient in hydraulic jump region and Wall drag coefficient are analyzed for the first time according to the momentum integral equation of boundary layer, and the calculation methods for boundary layer thickness, local resistance coefficient, drag coefficient and average drag coefficient are proposed. Compared with experimental data of Rajaranam, formula (9) and formula (26) coincide well with the test data, formula (29) coincide well with the test data when Fr1≥5.45 and when Fr1<5.45 the deviation becomes larger. Maximum error is 3.643% for calculation of conjugate water depth of hydraulic jump with the formula (34) and formula (35). ©, 2015, Xi'an Jiaotong University. All right reserved.

Lv F.,Wuhan University | Shu N.,Wuhan University | Gong Y.,Wuhan University | Guo Q.,Wuhan University | Shang H.,Xibei Engineering Corporation Ltd
Wuhan Daxue Xuebao (Xinxi Kexue Ban)/Geomatics and Information Science of Wuhan University | Year: 2014

An improved adaptive bandwidth calculation algorithm spectral space is proposed extending Comaniciu's method of calculating the adaptive bandwidth both in spectral and spatial space. A daptive bandwidths are used in the mean shift algorithm. with the traditional fixed bandwidth MS algorithm and Comaniciu's adaptive MS algorithm, the new adaptive MS algorithm proposed by this paper achieves better segmentation results.

Zhao Y.,Xibei Engineering Corporation Ltd | Ying H.,State Grid Corporation of China | Zhou J.,Huazhong University of Science and Technology
Water Science and Technology: Water Supply | Year: 2015

The operations of reservoirs produce enormous economic and social benefits but also impact species composition and habitat distribution of the riverine ecosystem. Hence, the realization of conservation and restoration of the ecosystem calls for reservoir reoperation. It is a widespread consensus that providing suitable ecological flow (SEF) for ecosystems is a useful way to cushion adverse effects. In contrast to the conventional methods that take a minimum ecological flow as a constraint, studies have been conducted to establish multi-objective operation models with an ecological objective recently. This paper considers two cascaded reservoirs: the Three Gorges Project (TGP) and the Gezhouba Dam in the middle Yangtze River. By concentrating on urgent ecological problems such as the reproduction of four major species of Chinese carp and the propagation of Chinese sturgeon, a series of monthly SEF was synthesized. Afterward, a long-term multi-objective optimization model that maximizes power generation and minimizes the water volume that violates ecosystem water requirements was developed to study the relationship between the two objectives. The non-dominated sorting genetic algorithm II method was applied to solve the proposed model. The optimized results show that according to the present water control operating regulations, the monthly amount of released water of TGP can be sufficient for ecosystem requirements except in October. The ecological model is better in improving the river ecosystem, but at the expense of power generation loss. Moreover, this method provides a set of operational nondominated schemes between the target objectives for decision-makers to select and could be useful for water resource management of reservoirs. © 2015 IWA Publishing.

Zou J.,Xian Jiaotong University | Zou J.,Xibei Engineering Corporation Ltd | Qu L.,Xian Jiaotong University | Dai G.,Csic No 703 Research Institute | And 2 more authors.
Jixie Qiangdu/Journal of Mechanical Strength | Year: 2015

For reducing the influence of truncation error on the accuracy of time domain averaging (TDA) induced by non-integer-period sampling, an improved algorithm of TDA based on fractional delay filtering (FDF) is presented. On the basis of analyzing the disadvantages of current methods of TDA and the characteristics of FDF, a presently improved method of signal truncation was used in the method to avoid the accumulation of truncation error and obtain a delay factor on each of the truncated signals, the reconstruction and resample for the truncated signals were implemented with FDF, and finally the arithmetic mean were computed after all of the truncated signals were added. The theoretical analysis and experimental results demonstrate that the method which fully makes using of the advantages of FDF on the change of delay factor, apparently reduces the truncation error of signals with non-integer-period sampling, and could obviously improve the accuracy of TDA without key-phase signal. © 2015, Journal of Mechanical Strength. All right reserved.

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