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He Z.,Zhejiang University | He Z.,State Key Laboratory of Satellite Ocean Environment Dynamics | Wu T.,Zhejiang University | Weng H.,Zhejiang University | And 4 more authors.
International Journal of Sediment Research | Year: 2017

Existing numerical investigations of dam-break flows rarely consider the effects of vegetation. This paper presents a depth-averaged two-dimensional model for dam-break flows over mobile and vegetated beds. In the model, both the consequences of reducing space for storing mass and momentum by the existence of vegetation and dragging the flow are considered: the former is considered by introducing a factor (1−c) to the flow depth, where c is the vegetation density; the later is considered by including an additional sink term in the momentum equations. The new governing equations are discretized by the finite volume method; and an existing second-order central-upwind scheme embedded with the hydrostatic reconstruction method for water depth, is used to estimate the fluxes; the source terms are estimated by either explicit or semi-explicit methods fulfilling the stability requirement. Laboratory experiments of dam-break flows or quasi-steady flows with/without vegetation effects/sediment transport are simulated. The good agreements between the measurements and the numerical simulations demonstrate a satisfactory performance of the model in reproducing the flow depth, velocity and bed deformation depth. Numerical case studies of six scenarios of dam-break flows over a mobile and vegetated bed are conducted. It is shown that when the area of the vegetation zone, the vegetation density, and the pattern of the vegetation distribution are varied, the resulted bed morphological change differs greatly, suggesting a great influence of vegetation on the dam-break flow evolution. Specifically, the vegetation may divert the direction of the main flow, hindering the flow and thus result in increased deposition upstream of the vegetation. © 2015 International Research and Training Centre on Erosion and Sedimentation / the World Association for Sedimentation and Erosion Research

Wang X.-F.,Zhejiang Guangchuan Engineering Consulting Co.
Electronic Journal of Geotechnical Engineering | Year: 2013

In situ monitoring plays an important role in the construction organization as one part of the information on construction. In the study reported in this paper we used three different methods namely the hyperbolic method, exponent method and Asaoka method. These methods are used to analyze the effect of the foundation treatment to forecast the final settlement and calculate the average degree of consolidation of the foundation through the in situ observation of foundation treatment. The study was done as part of an airport expansion project. At the same time this paper proposed one simplified calculation model based on the measured settlement and the stage loading method by Zeng Guoxi then calculated the degree of consolidation. Finally this paper made comparison with the result of the modeling calculation and the average degree of consolidation. The results showed this modeling method is reasonably accurate and feasible. © 2013, EJGE.

Chang X.,Zhejiang Water Conservancy and Hydropower College | Chengfa D.,Zhejiang Guangchuan Engineering Consulting Co.
Proceedings - 2nd IEEE International Conference on Advanced Computer Control, ICACC 2010 | Year: 2010

This paper deals with the application of least squares support vector regression (LS-SVR) with radial basis function (RBF) kernel in dam crack forecasting. In the process of LS-SVR, we performed the standard grid search and particle swarm optimization (PSO) to tune hyperparameters of LS-SVR. The results demonstrate that our PSO approach can identify optimal or near optimal parameters faster than the exhaustive grid search. Comparison with results from stepwise regression was also included, to evaluate the reliability of applying such a PSO method which avoids doing an exhaustive grid search. We found that our LS-SVR approach is promising in dam crack forecasting, however it cannot be used to extract the crack contributed by water pressure, temperature variation, and aging effect, respectively. © 2010 IEEE.

Shen Z.W.,Zhejiang Institute of Hydraulics and Estuary | Wang X.H.,Zhejiang Guangchuan Engineering Consulting Co. | Jin W.L.,Zhejiang Institute of Hydraulics and Estuary
Hydraulic Engineering II - Proceedings of the 2nd SREE Conference on Hydraulic Engineering, CHE 2013 | Year: 2014

In China, most of the offshore platform lied in the bohai sea, yellow sea and east China sea and south China sea, which is earthquake-prone area. Earthquake is devastating and unpredictable. It is important to assess the reliability of offshore jacket platforms subjected to seismic action. This paper presents the approach to calibrate of reliability of offshore jacket platform subjected to seismic action. The combination of loads are mainly investigated. The reliability of offshore jacket platform of QK18-1 in Bohai Bay related to 25-year reference period is 1.304, which is close to the conclusion of some existing researches. The results could provide significant reference for the design of offshore jacket platforms. © 2014 Taylor & Francis Group, London.

Shen Z.W.,Zhejiang Institute of Hydraulics and Estuary | Jin W.L.,Zhejiang University | Wang X.H.,Zhejiang Guangchuan Engineering Consulting Co.
Applied Mechanics and Materials | Year: 2013

Offshore jacket platforms under complicated and changeful ocean environments are subjected to various stochastic actions such as actions of wave, current, wind, ice, earthquake and their combinations. This paper presented the approach to calibrate of the reliability of the offshore jacket platform, and suggested all kinds of associated load cases. The combination of loads were mainly investigated. As an example, the reliability of offshore jacket platform of QK18-1 in Bohai Bay was verified. The result shows that the reliability of the offshore jacket platform related to 25-year reference period is between 2.7 and 3.39, which is close to the conclusion of some existing researches. This method would be used more widely for the design of offshore jacket platforms. © (2013) Trans Tech Publications, Switzerland.

Huang L.G.,Zhejiang Institute of Hydraulics and Estuary | Wang X.H.,Zhejiang guang chuan engineering consulting co. | Shen Z.W.,Zhejiang guang chuan engineering consulting co. | Zhang X.,Zhejiang guang chuan engineering consulting co. | Zhang L.P.,Zhejiang University
Advanced Materials Research | Year: 2014

Soil sampling was carried out on the experimental plot, and comprehensive analysis of characteristics of soil nutrient and physical and chemical environment based on the soil and water conservation monitoring site topography and vegetation etc., on the basis of present situation investigation. The plant selection analysis of different experiment plot was carried out combined with experiment village construction planning, and the plants by nature, on the basis of the different soil and water conservation monitoring sites have in common in Zhejiang province. Targeted put forward of the construction of the proposed plant and soil improvement measures, for each monitoring site experiment plot of provide the scientific basis for the establishment of soil and water conservation measures. © (2014) Trans Tech Publications, Switzerland.

Shen Z.W.,Zhejiang Institute of Hydraulics and Estuary | Wang X.H.,Zhejiang guang chuan engineering consulting co.
Advanced Materials Research | Year: 2014

Today to estimate the size of the rainfall on soil erosion comprehensive index is rainfall erosion force.This paper, by using routine weather stations rainfall data, such as the daily rainfall data of rainfall erosion force simplified model is set up, estimate rainfall erosion force, on the soil erosion quantitative forecast and science develop soil and water conservation measures is particularly important. © (2014) Trans Tech Publications, Switzerland.

Li X.,Zhejiang Institute of Hydraulics and Estuary | Li X.,Zhejiang Provincial Key Laboratory of Hydraulics Disaster Prevention and Mitigation | Li H.,Zhejiang Institute of Hydraulics and Estuary | Li H.,Zhejiang Guangchuan Engineering Consulting Co. | And 2 more authors.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2015

Crushing of the slag from Qincun Reservoir and the gravel-cobble from Yuxi Reservoir was studied by large-scale direct shear tests, and discarding parameters were introduced to investigate laws of breakage development from stratification planes of fractions and granular soil as a whole respectively. The results show that the relationship between discarding ratio Rk and nominal stress σ is linear for different fractions of the tested coarse-grained soils with σ varying in the research range. And difference of crushing of the two tested soils, which is mainly reflected in the grains from larger fractions, tends to disappear as grain size decreases. For coarse-grained soil as a whole, when σ varies in the range of 0-300 kPa, the breakage degrees of two soils are rather close. However, once σ varies in the range of 300-1 200 kPa, crushing of slags from Qincun Reservoir is more significant than gravel-cobble from Yuxi Reservoir. Besides, breakages of the two coarse-grained soils tend to be more remarkable as σ increases. ©, 2015, Academia Sinica. All right reserved.

Shen Z.-W.,Zhejiang Institute of Hydraulics and Estuary | Wang X.-H.,Zhejiang Guangchuan Engineering Consulting Co. | Jin W.-L.,Zhejiang University
Advanced Materials Research | Year: 2014

When more than one loads act on a structure, the combination of stochastic loads is generally considered in the design of the structure, Based on the theoretical derivation and numerical calculation analysis to the process of two common loads in Poisson square wave and Poisson impulse this paper presents the combination method of loads.i.e. The maximum intensity function of load combination is expressed by the cumulative distribution function in the limit state design. In addition, the result calculated during the limit state design is compared with those calculated by Turkstra and Monte Carlo methods and the analytical results show that the method proposed in this paper is feasible in the calculation of load combination. © (2014) Trans Tech Publications, Switzerland.

Hu D.-C.,Changjiang River Scientific Research Institute | Chi L.-Z.,Zhejiang Guangchuan Engineering Consulting Co. | Yang Q.,Zhejiang Institute of Hydraulics and Estuary | Wang M.,Changjiang River Scientific Research Institute
Zhejiang Daxue Xuebao (Gongxue Ban)/Journal of Zhejiang University (Engineering Science) | Year: 2015

To illuminate the development mechanics of a reservoir scouring funnel, the sediment deposition before a dam was simulated using a 3D numerical model. The 3D model used an unstructured, sigma grid, which fitted well complex boundaries of real rivers. The θ semi-implicit method, Eulerian-Lagrangian method were combined to discretize the governing equations, which made the computation stable. The parameters of the 3D model were determined by comparing the simulated results of the 1D and 3D models. The sedimentation process before the orifices of a reservoir was then simulated by the 3D model with calibrated parameters. The process of 20-year sediment transport and deposition before the dam of the Pakistan Karot reservoir was simulated, and the distributions of the flows, sediment concentration and deposition were obtained. The results indicate that: (1) in a reservoir, the sediment is transported and deposits in the main channel, at two sides of which intensive depositions of refraction sediment-carrying flows occur along the horizontal circulation before orifices; (2) with the aging of the reservoir, the high floodplain and deep channel are gradually advanced towards the orifices, the scouring funnel is then formed between the above intensive depositions and before the orifices. ©, 2015, Zhejiang University. All right reserved.

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