Advanced Materials Research Vols. 255-260

Abstract: In this paper, according to the reality that there is no mature Chinese national design criterion but partial enterprise standard for rock bolt crane girder in the underground powerhouse of large hydropower station up to now. Based on the geological conditions, the rock bolt crane girder was designed by using method of rigid body equilibrium. The reinforced anchoring measures for rock bolt crane girder in undesirable geology were studied subsequently by the experience of analogous projects. The stability of rock bolt crane girder in underground powerhouse was analyzed and evaluated by Finite Element Method (FEM). Then the bearing capacity of crane beam was researched by means of bearing testing. The results show FEM is practicable to evaluate the stability of the rock bolt crane girder and to guide the rock bolt crane girder designing. The results also show the reinforced anchoring measures are appropriate to displace the undesirable surrounding rock section by using concrete. The results of bearing testing show that the design of rock bolt crane girder and its anchoring measures are rational, and crane girder can meet to the requirement of safe operation.

Abstract: In this paper, based on the experimental measured cooling curves, it was solved that the inverse problem of non-linear heat conduct equation for Steel 1045 quenched by water using finite difference method and nonlinear estimate method. The volume fraction of constituent of austenite, pearlite, bainite, martensite and the non-linear surface heat-transfer coefficients in continuous cooling during quenching were calculated and simulated by mathematical transformation. The volume fraction of phase constituents in the quenched work piece of 1045 steel was tested subsequently. Then the temperature field and thermal stress field of Steel 1045 cylinder during water quenching was simulated by ANSYS. The study results show that the 2D transient temperature field of the cylinder specimen calculated by ANSYS during quenching coincides with the practical quenching process, and the results of thermal stress field simulated by ANSYS can guide quenching process.

Abstract: For mass concrete with the admixtures of limestone powder and water quenched iron slag (shortly called double admixture concrete) in dam of Jinghong hydropower station located at the downstream of Lancang river in Yunnan province, the mineral composition of double admixture was analyzed in this paper. And it is also studied by materials testing and microscopic analysis methods such as laser particle analysis, scanning electron microscopy, energy spectrum analysis, X-ray diffraction analysis and thermo gravimetric-differential thermal analysis that the hydration, hydrated product and mechanism of hydration process in the system of cementing and double admixture material system. Then the mechanical, thermal and deformation properties and the durability of the concrete with double admixtures were also analyzed by experimental methods. 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 or normal concrete. And the properties of the double admixture concrete in Jinghong hydropower station meet all kind requirements.

Abstract: The data transfer method for fluid structure interaction analysis using compactly supported radial based function (CRBF-FSI) is studied. It builds transfer matrix for data exchange and makes fluid and structure mesh use different shape and density unrestrictedly. Example of data exchange on 3D interface is studied. The efficient and the accurate of CRBF-FSI method are analyzed and also the influence of different compactly-supported radius is studied. The results show that CRBF-FSI method is suitable for FSI data transfer on complicated interface if compactly-supported radius is properly chosen. It has a bright future in practical use such as wind-induced response analysis in Wind Engineering.

Abstract: Since there are some characteristics such as correlation, repeatability and integrity during the gravity dam design process, an automatic gravity dam assistant design system was established by adopting C sharp programming language, Visual Studio Development Suite as well as material mechanics and Technology of Parametric Drawing. The System includes four modules: 3D geological modeling, gravity dam structure modeling, dam sections analysis and database management. These modules realized different specialty cooperation and offered many-side analysis such as: 3D finite element analysis, stability analysis, stress analysis, section optimization and report export.

Abstract: In this paper, the backward-facing step flow and the sediment transport downstream step were studied experimentally. The critical incipient bed shear velocity is obtained by the results of bed shear velocity and sediment incipient probability. It was found that the critical incipient bed shear velocity depends on the flow structures under the complex flow. By using the new critical incipient bed shear obtained in this paper and calculating the Shields parameter based on instantaneous bed shear velocity, the bed load sediment transport rate downstream step was given. The time history of the bed profile downstream step was calculated by bed load sediment transport rate and compared that obtained by the digital images. Good agreement was observed.

Abstract: Chaos and support vector machine theory has opened up a new route to study complicated and changeable non-linear hydrology time series. Applying the Chaos and non-linear time series based on the support vector machine regression principle, this paper proposes a method and its characteristic and the choosing of key parameters to forecast and set up models. According to Phase Space Reconstruction theory carry on reconstruction of Phase Space to monthly surface flow course, have discussed that probed into the non-linear prediction model of time series of Chaos of the support vector machine, application in the monthly surface flow, have introduce it through to the nuclear function of the base in the course of setting up the model of support vector machine, has simplified the course of solving the non-linear problems. The instance indicates that the model can deal with the complicated hydrology data array well, and there is the good prediction precision.

Abstract: The structure, processes and dimension of the river corridor landscape ecology supplement each other, which will be influenced by the water conservancy projects and result in the destruction of river ecological system. Together with the approach of ecological runoff, RVE will be sued in evaluating the protection of water conservancy projects to the ecology by controlling the flow. Make the Yangzi River as an example of evaluation and establish a management model of river ecology not only to provide ecological basis for controlling the flow in Sanxia Reservoir but also adjust the model according to the latest ecological conservation and research result.

Abstract: Based on the consideration of the performance, disaster prevention, relief and tunnel drainage requirement, the connected aisle becomes more and more important to the shield tunnel section with the construction of large quantities of shield tunnels. The construction mechanical behavior of the connected aisle is complex and difficult to simulate with exist method sometimes. In allusion to the numerical simulation of the construction mechanical behavior of the connected aisle in the shield tunnel which is built in the sandy strata with the high hydraulic pressure, a new calculation approach is put forward. The core idea is the coupling use of the stratum structure method and the load structure method. The new method is used in the construction mechanical behavior study of the connected aisle which is built in the shield tunnel across the Yangtze River in Wuhan subway. Some conclusions are drawn and some related advices are proposed based on the analysis of the numerical simulation.

Abstract: The climatic zone is characterized by alternate wet and dry seasons along Fujian coast. The vertisols experience periodic swelling-shrinkage during alternate wet and dry seasons. 16 soil samples from different profiles (0~20cm depth, 20~40cm depth)were collected from different regions in the research area. The paper shows the swelling-shrinkage behavior along Fujian coast in terms of morphology, particle content and physical properties of vertisols, The structure of the soil profile varies with depth, while the profile horizonation is weak. Crack network is usually observed on the surface. In addition, this paper investigated the effect of wetting and drying on the expansive chatacteristics of the soil. The test results show that after each cycle, the height of the soil samples increased. This indicates that the swell-shrink behavior of vertisols is not completely reversible. The swelling-shrinkage characteristics of soils become greater with stickier texture. Compared to undisturbed soils, the swelling-shrinkage behavior of disturbed soils are greater.