Abstract:A physics-based infiltration capacity distribution curve, which was calculated using the soil and rainfall data, was introduced into the Green-Ampt rainfall-runoff model to improve its performance. The improved Green-Ampt model was compared with the traditional Green-Ampt model and the Xin’anjiang model in two semi-arid basins in China and US, and then, the performance and applicability of the improved model in semi-arid regions were evaluated. The results show that in two semi-arid basins, the improved Green-Ampt model performs better than the traditional Green-Ampt model and the Xin’anjiang model. The added physics-based infiltration capacity distribution curve effectively reflects the changing of infiltration capacity with time and rainfall for the whole basin, and the results of infiltration and runoff generation calculated by the improved infiltration curve are more accurate. The flood in semi-arid region is mainly caused by the short-term and heavy rainfall, and the runoff is dominated by the infiltrated-excess surface runoff. Rainfall observation accuracy and rainfall intensity have great influence on the simulation accuracy of hydrological models. The improved Green-Ampt rainfall-runoff model can play an important role for the flood forecasts in semi-arid regions.

Abstract:The characteristics of hydro-logical cycle and hydro-chemical evolution of Nalenggele River Catchment were summarized and the programs of the regional water resources exploration and diversion were comprehensively proposed. Results show that the spatial-temporal difference of the hydro-logical cycle is distinct in the Nalenggele River. The runoff is mainly concentrated in the mountain area and varies greatly throughout the year. Besides, the dynamic inter annual or seasonal fluctuation of groundwater level is larger than ordinary arid basin and exhibits an increasing trend in wet season, which means that the water circulation conditions are ideal and water resources are abundant in wet season. More typically, both the surface water and groundwater contain unusual enriched elements of B, Li and K in the middle and lower reaches of the basin. The enriched elements are of continuous deep-source supply with annual runoff of at least several thousand tons, and the total amount of groundwater about 150 m in the alluvial fan is beyond 100-thousand tons. The conclusion can be deduced that the water transfer from the upper tributaries can not only increase the total amount of dissolved mineral elements such as B, Li and K, but also ensure the safety of the Qinghai-Tibet line for the leakage water from lakes in the source area. Finally, it is of great strategic significance to maintain dynamic water resource balance in the Nalenggele River.

Abstract:To analyze the effect of sponge measures on the reduction of rainwater runoff at the watershed scale, this study presented an optimal combination mode for the construction of sponge city system. An integrated flooding and water-logging model for the Macao River was established based on the Infoworks ICM model and following the code for the design of storm water management and harvest engineering to quantitatively evaluate the storage effect of storage ponds, hollow grassland and the permeable pavement sponge combination mode. The results show that the sponge combination measures have better effect on the reduction of rainfall runoff, flood peak discharge and flood peak time in the low-recurring period of less than 10 years. In comparison while the return period of rainfall reaches 10 years and above, the reduction ratio of runoff and flood peak discharge decrease to different extents, and the flood peak discharge reduction and flood peak time delay significantly decrease. After the implementation of the sponge measures, the annual runoff of the basin was reduced by an average of 39%, when all controlled blocks meet the control standards. Current design standards for rainwater can help support the pilot construction of sponge cities.

Abstract:Based on the concept and connotation of water-related eco-environmental carrying capacity, in this study the index system framework was constructed, which included the water(soil)resource subsystem, the water-related eco-environmental subsystem and the socioeconomic subsystem. According to the indicator selection principle, the analytic hierarchy process combining with the actual water resources situation, water-related eco-environmental problems and socioeconomic development characteristics of Changxing County, the water-related eco-environmental carrying capacity evaluation index system was constructed, which included two water resource indicators, ten water-related eco-environmental indicators and seven socio-economic indicators. Based on the built index system, the evaluation results show that the water resources surplus and deficiency level estimating index was 0. 711 9, the water-related eco-environmental quality estimating index was 0. 880 8, socioeconomic level estimating index was 0. 850 6 and the comprehensive estimating index was 0. 820 7 by using the carrying status comprehensive evaluation model for the Changxing County in 2014. These results indicate that the water-related eco-environmental carrying status in Changxing County in 2014 was generally in a good carrying status, in line with the actual situation.

Abstract:In order to study the hydraulic characteristics of bifurcated pipes in pumped storage power station when different units are pumped at the same time, combined with the shape and design parameters of bifurcated pipes in a pumped storage power station, the hydraulic characteristics of bifurcated pipes in the same unit with the same pumping and discharge were numerically simulated by using the hydrodynamic model. The results show that, within the scope of the study, the return flow and low pressure zone will occur in the bifurcated section of the same pumping operation, and the maximum head loss coefficient is 0. 5. Meanwhile, the flow pattern in the bifurcated pipe will deteriorate and the head loss will increase when the same hydraulic unit operates with the same pumping flow, but it is feasible from the hydraulic point of view.

Abstract:To make the prediction result of dam safety more accurate with support vector machine(SVM), a genetic algorithm-support vector machine(GA-SVM)dam safety prediction model was proposed based on the genetic algorithm optimization. With the minimum error of k-CV verification as the optimization target, the genetic algorithm was introduced to optimize the penalty parameter c and kernel function parameter g of SVM. The model took the influence factor as the input and the effect quantity as the output. Then the training sample data were used to train the support vector machine, and the trained model was used to predict the effect quantity. According to the 3σ criterion in the probability and statistics theory, the three-grade index and discriminant criterion of dam safety were established. Taking an actual large-reservoir dam as the case, the GA-SVM model of this dam was established and compared with the SVM model and stepwise regression model. The prediction results show that the predicted value of GA-SVM model is closest to the measured value, and its prediction accuracy is about three times higher than both SVM model and stepwise regression model. Therefore, the GA-SVM prediction model has a good prediction precision and can be used for the dam safety prediction.

Abstract:This paper proposed a grouting power time series prediction model, based on fuzzy information granulation(FIG)and grey wolf optimized support vector machine(GWO-SVM). The model establishment consisted of three major steps. First, the granular computing method was introduced to decompose the original numerical time series into a series of information granules for reducing the scale of the data. Second, based on the theory of fuzzy sets, the fuzzy set operator was used to carry out the fuzzy calculation for each information granular, so that the obtained fuzzy information granular can reasonably represent the original numerical point set. Finally, the support vector machine was used as a predictive tool, optimized by the grey wolf optimizer algorithm, and the information granules can be predicted quickly, accurately and robustly. Taking an actual project as an example, this model was used to predict the fluctuation range and trend of grouting power time series during the grouting process. After the performance evaluation and comparative analysis, the feasibility and effectiveness of the prediction model were verified.

Abstract:In order to solve the problem that the static model is often used in seepage safety evaluation with neglecting the dynamic change characteristics of index data, the functional data analysis theory is introduced into the scalable evaluation model where the discrete index data is transformed into the continuous function. A comprehensive index system of seepage safety was established including the basic index and the derivative index. Matter element analysis and correlation function construction method suitable for the functional data were proposed, and a dynamic and scalable evaluation model of dam seepage safety was established based on functional data analysis theory. In addition, the combination of analytic hierarchy process(AHP)and entropy weight method was used to determine the index weight. The time weights reflecting the importance of different time in dynamic evaluation were established. The seepage safety monitoring data of a concrete gravity dam in China was analyzed. The results show that the seepage safety state fluctuates from grade II to grade III, which is basically consistent with reality, indicating the effectiveness of proposed model.

Abstract:To investigate main influencing factors of repair efficacy for the fatigue crack of FRP-repaired damaged steel members, the finite element method was employed to conduct the parametric analyses of the stress intensity factor(K)for FRP-repaired central-cracked steel plate. The results show that the increase of the FRP cross-sectional stiffness, FRP width and FRP length can decrease the factor K. The values of factor K will not change any more when the FRP length exceeds a certain value. The K can be reduced by decreasing the adhesive thickness and increasing the adhesive shear modulus. The local debond leads to an increase of K value. K values of the single-sided repair are much higher than those of the double-sided repair. Moreover, the increase of the FRP thickness in the single-sided repair cannot effectively reduce K values.

Abstract:To investigate the effects of soil on the seismic energy response of the equipment-structure system, the shaking table test and the real-time substructure shaking table test of an equipment-structure-soil system were carried out in this study. The energy response of the equipment-structure system in the case of rigid ground was compared with those of considering the effects of soil. The input energy of the equipment-structure system was found to decrease significantly due to the effects of soil. Furthermore, the effect of soil led to a change in the time distribution characteristics of total energy input. Additionally, the energy response of the original equipment-structure system was also deduced based on the similitude scale factors, which resulted in significant errors compared with those of considering the effects of soil. Therefore, it is imperative to pay an attention to the effects of soil in the design of equipment-structure systems.

Abstract:To promote the engineering application of the new spread hollow slab bridge system, a calculation method for lateral load distribution factors was proposed. The beam spacing, span length, bridge width and beam depth were selected as key parameters affecting the lateral load distribution behavior of bridge structures. Finite element models for bridge configurations with different parameter combinations were established using the ABAQUS software, from which moment and shear distribution factors were determined for one-lane and multi-lane loaded cases and effects of aforementioned parameters were analyzed. Furthermore, design formulas of moment and shear distribution factors were obtained via the nonlinear regression analysis method. Comparisons with test results of a practical bridge indicate that proposed formulas are reliable and applicable for structural designs of spread hollow slab bridges in the engineering practice.

Abstract:In order to reveal the influence of different inclination angles of tip winglets on the efficiency of horizontal axis wind turbine blades, five kinds of tip winglets with different inclination angles were designed. The aerodynamic performance of tip winglets with different inclination angles was analyzed by the structured grid technique and the Computational Fluid Dynamics(CFD)method. Thereafter, the results by analyzing and comparing their aerodynamic performance show that the output power and rotor power coefficient of five kinds of wind turbines are all significantly improved with winglet, and the maximum output power increases by 16. 73%, while the rotor power coefficient increases by 4. 41%. Winglets with larger inclination angle can more increase pressure difference between the upper and lower airfoil section of the blade and the bend moment of the root of winglet is smaller. Besides, winglets with large inclination angle can significantly improve the tip flow around the blade, break up the strong vorticity dragged at the tip of blade, and reduce the loss of energy at the blade tip.

Abstract:This paper proposed a ratio consensus control method based on the Hamiltonian energy theory. By adjusting the rotation speed of flywheel energy storage unit, the ratio consensus control of the system was achieved, and the internal power of the flywheel energy storage system (FESS) is reasonably distributed. First, the portcontrolled Hamilton (PCH) model of the flywheel energy storage unit was established, and the portcontrolled Hamiltonian model with dissipation (PCH-D) was obtained by using the feedback stabilization principle of the PCH system. Then, the problem of ratio consensus control of the flywheel energy storage system was investigated. The speed regulation of the flywheel energy storage unit was realized by using the Hamilton energy forming control strategy to ensure that all the flywheel energy storage units could store and release energy under the same ratio and realize the reasonable distribution of power. Finally, the effectiveness of the proposed control strategy was verified by simulation.

Abstract:In order to seek a more optimal control system, this study built a DC-DC buck converter and conducted the system modelling according to its parameters, based on which three controllers were designed, including a state-space controller with non-overshooting and non-undershooting(NOUS)algorithm, a NOUS controller with observer and a proportional-integral-derivative(PID)controller. The step responses and transient responses of the converter with 3 different control systems when load changes were shown by an oscilloscope, so that their control performances could be compared. The results indicate that the state-space controller based on NOUS algorithm has better transient response and control precision, while PID controller has advantage in robustness. NOUS controller with observer preserves the advantage of fast convergence, but will lead to amplifying the errors in the system modelling and cause worse control results.