Applied Mechanics and Materials Vols. 580-583

Abstract: The impact of the flood discharge water flow from a high dam is rather great on the slab of a plunge pool, and may cause damages to the plunge pool and consequently endangers the dam body safety. Therefore, a reverse arch slab model was established on the base of a study on and a simulation of the rational scale of gaps between the plates of the plunge pool slab. The model was an arch ring containing 7 slabs. The uplift force time history of each slab was measured, and the uplift force power spectrum and probability density were analyzed. The test result shows that the uplift energy mainly centers in 0-15Hz frequency bandwidth, and mostly within 1Hz. It belongs to a low frequency and big amplitude vibration.

Abstract: An egg-shaped is consisted of four parts: One arc bottom, two side circular arc arch and one circular arc roof umbrella arch. It is complex shape. Aiming at traditional methods there are complicated and the defects of inaccurate. on the basis of summarizing the predecessors' research, Based on the normal water depth basic equation mathematical transformation of egg-shaped sections, the interrelation between dimensionless water depth and the dimensionless parameter were analyzed, We use the power function as the formula form, with minimum residual standard deviation as the goal, the coefficients of the formula can be calculated based on the theory of optimization and regression. Then, we get calculation formula for normal water depth. This formula is not a piecewise function, and need not to choose the suitable formula according to the dividing flow. The results can be directly calculated. Results of the example calculation and error analysis showed that the maximum relative error of normal water depth was 0.675% respectively in the utility range (The ratio of water depth divided by height of tunnel is from 0.05 to 0.85). Using this algorithm, above 92 % of the computation error on normal water depth was less than 0.25%. The average error of the formulas was not more than 0.118% .The hydraulic calculation formula will be widely used in engineering design and project management due to its high accuracy and simple form.

Abstract: In order to alleviate the contradictions about water resources shortage and socio-economic development in Northern Shaanxi, the water resources and their availability were studied. Through use the method of surface water resources deducte river ecological basic flow and flood discharge, calculated the surface available water resources and total available water resources of Northern Shaanxi, summarized their distribution characteristics. Study result showed that the available water resources of Northern Shaanxi is low, only 1.6 billion m³, available rate is 40%, water resources and their availability principally distribute in Yulin.

Abstract: Downstream sinking technology of flexible mattress has wide application in erosion protection、berth firm and bank protection. During sinking of flexible mattress, the distance get gradually between the landing position of the mattress and the laying mattress ship, then the suspense length and mattress’s self-weight are also increase because of the ship’s move. Therefore the tension in mattress is also change continuously, so the calculation of the tension becomes difficult. By using lumped mass method, the mattress can be separated into several lumped mass which are connected using non-mass springs, with the laying distance increase, the length and self-weight of the mattress can be increase gradually, and according to forces equilibrium equation, the tension and profile of the mattress can be obtained.

Abstract: The flow of bend reach is complicated, which is difficulty for intersection of ship,and is accident prone. According to the lower reaches of the Hanjiang River MaKou reach of ship model test results, the relationship between channel width and flow are summarized when ship navigation sail in bend reach, which indicated that at approximately the same speed, navigation width of sailing through the bend upward are much smaller than down. As velocity or flow angle increases, the ship track width is broader, and channel width is also broader. the ship control and peer safety management points are forwarded in the lower reaches of Hanjiang river bend, which can provide reference for similar engineering designand research of waterway.

Abstract: In order to improve the accuracy of river network hydraulic model, extended kalman filter was used for real-time updating model states. In a simulation example of a river network composed of 14 channels, it systematically analyzed the effects of process and measurement noises on state correction. The results show that the extended kalman filter is able to effectively carry out data assimilation of non-linear river network system, and big process noise in combination with relatively small measurement noise is recommended for state correction.

Abstract: Understanding the influences of water level on seepage stability of tailing bay is an important topics in hydraulic engineering design. The seepage stability of tailing bay under different water level was calculated with the numerical simulation software FLAC3D and the change laws of water pore pressure and saturation line in the dam was analyzed. The results show that the saturation line in the dam is a parabolic curve and the pore pressure changes in layers. With the increasing of water level, the saturation line in the heaping dam ups rather obviously while it is not obvious in the initial dam. The maximum pore pressure in the bottom of the dam increases with the relationship of water level up, the shallow of the saturation line is in the heaping dam heel.

Abstract: The temperature distribution and the flow resistance of air-cooled concrete aggregate are investigated in order to provide engineering guidance for the energy economization and design optimization. First, an aggregate bin is down-scaled and installed on an indoor experiment table, then tests are performed for different aggregate sizes and different inlet air velocity, with or without upper air duct. The results show that with the decrease of aggregate size, the temperature distribution turns more uniform, but the flow resistance increases; with the increase of wind velocity, the cooling rate is enhanced, but meanwhile the flow resistance is increased. So for different size of aggregates, an optimal wind velocity exists. Having an upper air duct not only enhances the cooling rate but also increases the cooling uniformity.

Abstract: Sensitivity analysis of model parameters is a rock fill parametric inversion analysis method to determine the unknown parameters. Traditional sensitivity analysis is basically a lot of trial or the method of single factor analysis based on a large amount of calculation, but, unable to reflect the real situation. The method of particle swarm optimization based on neural network based nonlinear mapping relationship between model parameters and displacement to finite element simulation of dam deformation. Basing on the orthogonal design, the methods of range analysis and variance analysis method were used for sensitivity analysis of the parameters of Duncan E-B model and the impact of various parameters on the dam displacement, and then it can be as the parameters of rock fill dam provide basis for determining the unknown parameters inversion.

Abstract: In order to investigate the groundwater level and quality, and study the groundwater contaminant in vertical and the dynamics relation in different aquifers, the place of sampling and monitoring need to be installed in the relevant position of the aquifers to differentiate groundwater from different aquifers. In recent years, groundwater monitoring and sampling system has made great progress, this paper focuses on the current study and development of groundwater monitoring well technology, and analyses the development and the applied direction of monitoring well technology from single-well monitoring to multi-level monitoring, which would provide scientific references for domestic related and groundwater contaminant.