Applied Mechanics and Materials Vols. 90-93

Abstract: The triangular taper penetrating frame is always used at the flood and bank protection. It is given that the tendency of longitudinal and lateral water surface profile and change of velocity near the triangular taper penetrating frame by the flume generalized model experiment and compared with the flow structure near the triangular taper penetrating frame with beach protection construction or not. It points out the triangular taper penetrating frame can protect the beach better.

Abstract: According to the investigation and supervision on current water quality in Hefang Reservoir, the single factor and eutrophication evaluation on the current water environment is given. Total phosphorus (TP) in most water areas is above the Ⅲ grade, total nitrogen (TN) is betweenⅡ~Ⅲ grade, and the TP is obviously beyond the standard, keeping at the stage of change from mesotrophic to eutrophication. By calculating the COD, TP and TN water environment capacity, the employed environment capacity of TP has already exceeded the carrying capacity of the reservoir. At last, the protecting measures of the water resources in reservoir are put forward, including engineering measures (such as the rural sewage interception project, vegetation renovation project and aquaculture control) and non-engineering measures.

Abstract: For roller compacted concrete (RCC in abbreviation) with the admixtures of limestone powder and water quenched iron slag in dam of Jinghong hydropower station located at the downstream of Lancang River in Yunnan province, the raw materials and mix proportion of the RCC with limestone powder and water quenched iron slag admixtures were studied by materials testing and X-ray diffraction analysis method. Then the mechanical properties, thermal properties, deformation properties and the durability of this RCC were also analyzed by experimental methods. The elastic modulus and creep degree of this RCC were studied specially by the method of experiment and nolinear fitting. The study results show it was theoretically feasible that adopting the double admixtures as the admixture of the mass hydraulic concrete which can be roller compacted concrete. And the properties of this RCC in Jinghong hydropower station meet all kind requirements.

Abstract: Aiming at the pivotal project is decorated jointly by sluice and pumping station, thus the relationship between each other is more complex. By using 3-D finite element software ABAQUS, the structure of pumping station was studied. Two methods were used when modeling and analyzing. For the method 1, only the model of pumping station was built and the check sluice was taken as a side load when calculating. For the method 2, the whole model of the joint hub of sluice and pumping station was built. The displacements and strength of the structure of pumping station can meet the requirements according to the calculated results. There is little difference between the calculated results of the two kinds of methods by comparison, but for the method 1, the calculations about displacements are all unsafe and it should be given enough attention, thereby the reliability and security of the design of similar projects will be guaranteed.

Abstract: After substituting with ordinary Portland cement for geological defaults in resistance rock-masses of the dam abutments in Xiaowan hydroelectric station, it was necessary to make unsubstituted sections be reinforced by means of high pressure consolidation grouting. So it was before grouting and reinforcing that several productive experiments on high pressure consolidation grouting were carried out in the representatively and typically geological sections chosen in situ. Results indicated that desired effects for geological defaults in the dam abutments could be gotten after grouting when the distances to orifice and grouting pressures were 2m, 3m, 5~7m and 3.0MPa, 5.0MPa, 5.0MPa on the first section, the second one and the following ones of the orifice, respectively. And the grouting manners which were orifice enclosed and grout cycled in holes were adopted. Eventually, all of the grouting parameters could be used in much larger districts in projects to consolidate better.

Abstract: The flow characteristics of an aerator inserted on the chute with a concave surface is more complex than that of on the straight chute. The area of the air intake of the aerator is a very important factor which influences the cavity size of jet flow after the aerator, the air pressure in the cavity and air concentrations in high-speed flows along the chute. The present project focused on the air intake of an aerator inserted on a model chute with a concave surface. How the area of the air intake of the aerator and the radius of chute arc affect flow characteristics are investigated. The air pressure in the cavity was indirectly derived from the jet trajectory equation. It is demonstrated that the cavity length increases with, and the air pressure in it decreases with the increasing of the air intake area at first, and then it remains unchangeable for a discharge even though the air intake area continues to increase.

Abstract: The Catanchor Coefficient Method is widely adopted because of its simplicity and convenience. However, how to determine the value of catanchor coefficient is still a problem. In this paper, four typical large prestressed piers were analyzed via Finite Element Method (FEM) and the relationship between the catanchor coefficient and the tensile stress occurring inside the controlling part was studied. The results we obtained indicate that the tensile stress decreases nonlinearly when the catanchor coefficient increases. Moreover, it changes quickly when the catanchor coefficient is within the range from 1.10 to 2.00 but slowly when that is from 2.00 to 3.00 in contrast. Based on our conclusions, the range from 1.50 to 2.00 of catanchor coefficient is advised with the data of related prestressed piers.

Abstract: Division of flood seasonal phases for reservoir can achieve reasonable adjustments in the flood control levels,and the purpose of improving water use efficiency. This paper refers the recent developments of the division of flood seasonal phases for reservoir research results, applications currently used three kinds of quantitative analysis method for reservoir flood phases. Tanghe Reservoir in Liaoning Province as an application example of the flood seasonal phases. The comprehensive analysis of 3 kinds of theoretical and computational methods based on the results obtained for the optimization of Tanghe Reservoir flood season program.

Abstract: Beizhangdian watershed is a typical semi-dry and semi-humid region, where human activities have little effect on the hydrological cycle. Based on a 30-year hydrological observation data, the precipitation, runoff, and rainfall-runoff relationship were researched by the hydrology statistics analysis methods. The results indicated that the inter-annual change of rainfall-runoff of the watershed is remarkable, the annual distribution of rainfall-runoff is extremely uneven, and rainfall-runoff mainly occurred in flood season (June ~ September). There is a good uniformity between the variation tendency of annual rainfall and annual runoff in time and amount, the correlation coefficient of rainfall and runoff is 0.74, the value of the F-test is 4.23.

Abstract: After the excavation of abutment slope, the stress redistributed and the rock mass quality degradation damaged. According to fore-and-aft change of stresses for excavation, the authors divided excavation area and chose suitable mechanical parameters of rock mass for different excavation area. We used theory and methods of unloading rock mass mechanics and used elastic-plastic viscous damage mechanics model to give 2-D finite element analysis of stress and strain for typical profiles. And then we analyzed the changes of stress and deformation of the slope at nature and unloading conditions, analyzed deformation and stability at different reinforcement areas of the slope to choose reasonable reinforcement area. Strengthening plans of rock mass are analyzed and compared to choose reasonable reinforcement plan. The research results herein can offer beneficial reference for the design and the construction engineers.