Advanced Materials Research Vols. 594-597

Abstract: Taking limit equilibrium calculation program SLIDE for the platform and establishing two-dimensional model of excavation slope. Based on unloading rock mass mechanics theory and method and considered the natural, excavation, reinforcement, water, rainfall, and other complex conditions to Study on the stability of slope during construction and operation, then using the outcome of the limit equilibrium method to give their assessment of slope stability. Analysis pointed out that : the high excavation slope basic in a stable state.

Abstract: A commercial CFD software was used to simulate and predict a centrifugal pump performance. In this paper，the influences on the numerical simulation results using different turbulence models and different leakage flow assumptions were studied. The simulations are based on RANS with the and SST turbulence models. It is found that SST turbulence is better. Also the influence of the leakage flow was studied.

Abstract: Applying the methods of stable isotopes and hydrochemistry to study the leakage from dyke is an effective way. But men only qualitatively analyzed and judged the problem. The authors attempted to perform the analysis of fuzzy clustering by applying the method of fuzzy clustering that stable isotopes and hydrochemistry values of 22 water samples were taken as index characteristic values and endued different weightings, combining some dyke. The clustering result showed that there was strong correlation in the data of stable isotopes, Cl- and TDS among the water samples of T12 borehole, gushing water 5m north of T9 borehole, river water and the effluent of drainage ditch north of T9 borehole. It is a proof to judge the leakage path that the water samples may has the same replenishment source.

Abstract: In the 10 million Kw daily peaking capacity project of a Power Station, the daily average flow is 10000 m3/s, the starting passing dam flow is 2800 m3/s, 10000m3/s and 17200 m3/s, and the maximum turbine flow velocity Q is 7200 m3/s. Based on the adjustment and operation model mentioned above, this article conducts the numerical simulation of load increment and load rejection adjustment operation of the power station, the motion law of single oblique wave caused by the turbine flow and its time-varying process at the dam upstream river.This article also analyzes motion law of non-constant wave at the dam upstream river and its influence on the navigation flow condition when the single oblique wave passes the approach channel entrance area, and then calculates relatively accurate hydrodynamic parameters.In order to meet the navigation standards,we adopt the optimization scheme in which power units are divided into two groups and operate at 5 minutes interval.The calculation results indicate that they can all meet the navigation flow condition.When the power station jointly perform the load rejection adjustment operation and ship lock single-gates filling, the wave height in approach channel exceeds the standard,so the optimization scheme of time-staggered operation of the power unit and ship lock is adopted to reduce the wave height,and the results meet the navigation standard,it is the best optimization operation scheme of power unit to guarantee the safe operation of the river.

Abstract: Dam safety based on risk analysis methodologies demands risk quantification of the earth-rock dam project, and estimation on the failure probability of earth-rock dams is a major concern in the dam safety management. Due to numerous uncertainties, structures of the reservoir are involved leading to risks that may finally cause dam failure. The risk identification was firstly investigated according to the actual project. Subsequently, method of expertise was presented to estimate odds of the presence of each link in dam failure modes quantitatively. The reservoir composed of several dams in South China was taken as a case. The failure probabilities of each dam were obtained and results showed that risk of No.5 dam was relatively higher in all the dams. The research is of great significance to the dam safety management.

Abstract: Corrosion of steel pipeline can form numerous leaks, reduce service life of pipeline, and make large losses. Use of nonmetallic pipeline can solve the problem. Glass fiber reinforced plastic pipeline is nonmetallic pipeline. It can be installed conveniently, would not corrode in electrochemistry environment, and its service life is very long. So, it is widely used in many fields such as petroleum, city water supply, waste water processing, etc. In the paper, hydraulic calculations of pipeline are researched, and frictional resistance losses of water in glass fiber reinforced plastic pipelines with different diameters are measured. Based on experimental data, errors between experimental values and calculation values of formulas for hydraulic calculation are analyzed. The formulae to calculate the frictional resistance in glass fiber reinforced plastic pipeline are recommended.

Abstract: The comprehensive evaluation of the dam-break consequences is an issue of crucial importance for defending natural disasters, protecting socio-economic and sustaining ecological development. The consequences of dam-break were analyzed, including life loss, economic loss and the social and environmental influence. The loss of life evaluation based on the improved Graham method was introduced. Depth, velocity and other hydraulic parameters of dam-break flood were obtained by the three-dimensional numerical simulation, which has proved to be a useful tool for dam-break consequences. AHP method was adopted to measure the weight of each factor. Grey fuzzy comprehensive evaluation of dam-break consequences was proposed. QING LINJING reservoir in Shenzhen was taken as a case. The results show that it will cause serious incidents once QING LINJING reservoir dam breaks.

Abstract: Closed concrete cut-off wall has been widely used in the reinforcement projects of earth-rock dam. However, the research on the cut-off wall was rare. In order to discuss the stress state of the wall under different engineering conditions, a coupled numerical model was established by considering coupled interaction, including contact between wall and dam, and coupling of stress and seepage. Taking the earth-rock dam which built on common foundation for example, the stress distribution of the wall and influencing law of different factors were mainly researched, including elastic modulus of the wall, deformation modulus of the dam filling materials, permeability coefficient of the dam foundation, etc. The conclusions had reference significance for the application and design and calculation method of concrete cut-off wall in the reinforcement projects of earth-rock dam.

Abstract: Aimed at the representative project which is protected by the downstream sediment storage dam, three dimensional flow velocity field in local scour area around the separate bridge pier via physical model test was studied. The influences of shaping the eroded pit caused by the velocities in different directions were analyzed. The distribution results of flow velocity field in local scour pit near the pier protected by the sediment storage dam, deduced from the paper, will provide references for the defensive design of bridge projects.

Abstract: Due to the shortcomings of conventional methods, the temperature control in rapid construction of Guandi dam is less effective. Then improved measures are designed and implemented based on the dynamic control method of pipe cooling, which depends on the real-time adjustment of five factors affecting pipe cooling (beginning time of cooling, lasting time of cooling, water temperature, rate of flow and direction of flow). The monitoring and feedback calculation are conducted. It is found that the newly-designed measures have obvious effect, and that there are no harmful cracks in the whole construction of Guandi dam. The conclusion is that it can effectively solve the problem of temperature control and crack prevention of high RCC dam via these measures, and provide some guide and reference to other similar projects.