Applied Mechanics and Materials Vols. 170-173

Abstract: The working principle of concrete pumping hydraulic system was analyzed. And base on the AMESim software, the complete simulation model of concrete pumping hydraulic system was built. A simulation was made to get the dynamic characteristics curve of hydraulic cylinder velocity and displacement at some specific conditions. The simulation results indicate that the model is reasonable. Comparative simulations of the pumping hydraulic system with different positions of buffer structure were carried out to study the relationship between buffer effect and the buffer position which can be used to provide theory basis for deeper study of the hydraulic shock.

Abstract: The finite element analysis model of Zhuziqing tailings pond is established by using the finite element method (FEM) analysis software ANSYS based on hydrological conditions, engineering geological conditions, tailings silt dynamic triaxial test results and the foundation rock-soil wave velocity tests results. Then it was studied that the dynamic characteristics and dynamic response of Zhuziqing tailings dam under seismic loads. Results show that dynamic shear modulus of tailings silt increase as dynamic shear strain decreasing and increase as the increasing of confining pressure or consolidation ratio under the condition of isotropic or anisotropic consolidation. But the variation law on damping ratio of tailings silt is just opposite to that of dynamic shear modulus. Results also show that under the dynamic peak acceleration 0.2g of seismic wave, response acceleration of Zhuziqing tailings embankment reached the peak at the time of 2.58s, and the response peak acceleration is 5.24m/s2 at the top of this tailings embankment.

Abstract: As the support structures of building for crossing river, piers of bridge and/or aqueduct are generally arranged in tandem along the river direction, the fluid dynamic forces are main lateral loads acting on the Piers. Two-dimensional fluid computations have been performed using LES model to investigate the flows around three circular piers in tandem arrangements at a supercritical Reynolds number, Re =8.76×10⁶. Both center-to-center spaces are L/D=2.6. The flows and fluid-dynamic forces obtained from the simulations are analyzed. The results can provide the basis for the dynamic design of the supporting structures of the aqueducts.

Abstract: Reservoir landslide is a severe geological hazard which is caused by the hydrodynamic change due to rainfall and fluctuation of reservoir level. The hydrodynamic change and its influence on landslide stability of Qianjiangping landslide before and after impoundment of the Three Gorges Reservoir are studied combining with its hydrogeological structure. There are two relatively independent hydrogeological units on both sides of the slipband. Before impoundment, the outlet of groundwater under slipband is above the river level, the supply and discharge of groundwater is in equilibrium, and the excess pore water pressure at the bottom of slipband is smaller or not exists. After impounding, the outlet of groundwater is under reservoir level and the discharge of groundwater is hindered, so the excess pore water pressure at the bottom of slipband will rises and the safety factor of the landslide will decreases. Combing with other factors, the stability of the landslide will further decreases and lead to landslide failure finally.

Abstract: Now human error has caused lots of dam-break accidents home and abroad, but there is few studies about the human error in dam-break accidents. So more than 3500 dam-break accidents from 1954 to 2010 were researched and three of them were exactly analyzed in the paper to find out the real pattern and connection, in order to reduce and prevent similar mistakes happening again and meanwhile provide some positive reference.

Abstract: Karl Valley Quarry is the main quarry for the construction of the Pubugou Hydropower Project. With its developed faults ,veins ,dense joint-relief zones, deep pressure-relief zones and fissure, the slope has the possibility of integral and partial instability in the densely blasting and excavating process).Based on the rock elastic-plastic equivalent constitutive relations of joint-anchoring, by using the elastic-plastic element finite element method, the slope excavation and reinforcement as well as the stability is numerically simulated and analyzed. In addition, the reasonability of the initially drafted schemes for construction sequences and anchoring are evaluated and some valuable and instructive suggestions have been proposed to the engineering construction relevantly.

Abstract: Abstract. In order to generate mesh for arch dam abutment slip block automatically, virtual grid method is proposed based on grid-based automatic generation algorithm. The proposed algorithm avoids generating initial grid in one time, but intersects the model with a series of plane sections firstly. Then form initial grid by using vector intersection method for adjacent sections. By modifying initial grid, a layer of mesh is formed. The algorithm proposed can better adapt to complex topography and generates hexahedral meshes for the block of arch dam abutment automatically. The method can present data for limit equilibrium analysis and numerical calculation method such as finite element method. Based on original topography and structural plane data, the automatic identification, generation and meshing of arch dam abutment block is accomplished.

Abstract: According to the convenient using principle of cloud computation, the control equation and boundary condition of point source with free water surface are considered, the basic analyzing solution is obtained, the Green function representation is discussed., the discrete calculation expression and calculation procedure are proposed, two-dimensional graphics of the Green function’s real and imaginary part are plotted.

Abstract: Deep crack of high slope in the deep-cutting canyon region is a special geological phenomenon which exists in hydropower engineering in the west of China. High steep rock slopes are usually chosen as action sites of dam abutment. However, many deep cracks are often discovered in the depth of these high slopes. And irrefutably deep cracks greatly influence the stability of the engineering. By taking the deep cracks of left bank in Jinping I hydropower station as an example, formation mechanism of deep crack in high slope is partially revealed in this paper. Deep cracks were result of release of high geo-stress including body stress and tectonic stress when external environmental condition changed (such as river valley deep-cutting). Geometry and mechanics characteristics of discontinuous are internal factors result in the formation of deep cracks; deep cracks maybe have stepped-up process when combination of discontinuous is unfavorable; and intense release of high geo-stress caused by valley deep-cutting is external factor. In this paper, different combination of discontinuous was analyzed, and the formation process of deep cracks was simulated by DDA method. It concludes that the formation of deep cracks go through a series of complex process including river valley stress concentration caused by intense unloading - the high slope tension crack caused by horizontal stress release- part of the tension crack rock mass generates shear-tension crack downward along the slope under gravity”, etc. Research on this subject is a theory support for excavation and reinforcement of high slope where deep cracks exist.

Abstract: This paper mainly introduces how to use the software of Marc to calculate the displacement and stress of the sluice. The finite element model which concludes the sluice, piles and foundation was structured for calculation and analysis using the contact analysis function provided by the program. the displacement and stress of the massive structure was worked out to estimate its whole stability and evaluate workability state of the sluice under different structures. The example shows that the results of 3D finite element analysis can be used to accurately reflect the state of the buildings overall strength and displacement. The integral floor structure of contrary arch floor sluice is better than the separated floor structure to adapt to the foundation uneven settlement, but the separated floor structure of contrary arch floor sluice makes stress form more reasonable.