Applied Mechanics and Materials Vols. 275-277

Abstract: Firstly analyzed the stability of blocks with block theory and secondly evaluated the stability of blocks with three-dimensional limit equilibrium method and finally evaluated the whole stability of slopes. Stability analysis for the slope of Maerdang hydropower station shows that natural slopes which belong to the upstream of Hadehei ditch on the right bank will not occur wedge slide, tailrace slopes of hydropower station have not sliding slopes searched which are in potential slide, if taking some measures to reinforce the stability of man-made slopes on the face rock-fill hub, which may meet the demand of the specification.

Abstract: Based on the relationship between complex frequency and hysteresis damping coefficient, the formula of equivalent damping ratio of concrete-filled steel tubular arch bridge is deduced. Compared the calculated equivalent damping ratio by finite element model with the measured result, it is shown that the formula deduced in this paper is simple and practical, and can satisfy the engineering demand. At last, the formula given in this paper is closely related to hysteresis damping coefficient of material, with different hysteresis damping coefficient, the equivalent damping ratio will differ a lot.

Abstract: Used static finite element method to analyse the clay core rockfill dam of laojunshan reservoir whith Duncan-Chang E-B model. The results shows that the maximum of stress level is 0.78 under completion mode, and the maximum of stress level is 0.9 under normal operating condition. The stress and displacement value of the dam as well as its distribution rule is normal, and the maximum of stress level is less than 1. The possibility of occurring hydraulic split for core-wall is very small, and the dam is in a safe state.

Abstract: Seismic liquefaction is a major geological hazard of earthquakes. In the paper, the earthquake liquefaction of subway engineering in GUANGZHOU is calculated based on the standard penetration test method according to the rules of code for seismic design of buildings, specifications of earthquake resistant design for highway engineering, code for water resources and hydropower engineering geological investigation as well as the railway engineering anti-earthquake design specification. It is concluded that different code have very different result on sand liquefaction discrimination. And the data selection is a key factor when we discriminate sand liquefaction. The shortage of codes is evaluating the site liquefaction according to the data of points. The conclusions have positive role for engineering seismic liquefaction discrimination and the seismic liquefaction mechanism research.

Abstract: A 3D water contained space model for calculation of frost-heaving load on lining is presented in this paper. After the calculation and analysis some key points on characteristics of frost-heaving pressure up on lining of rock tunnel constructed in severe cold regions are concluded.

Abstract: To solve the problem of sediments on seismic response of concrete dams, pressure wave formula of saturated porous fluid-solid two-phase medium was derived from the Biot’s consolidation theory, and was determined the seismic response magnitude of sediment on concrete dam. Sediment was regarded as elastic-plasticity. And the method was applied to analyze the influence of sediments density, cohesion and friction angle on dam seismic response. Finally, a typical example is analyzed. The result shows sediments are significant on dam seismic response.

Abstract: In order to investigate the seismic behavior include hysteretic curve, skeleton curve and stiffness degradation, four masonry structures with different details are tested under pseudo-dynamic test and low cycle lateral load test. One kind of full-scale building is confined masonry with tie-column and ring-beam. Other is common brick masonry. Test results indicate that the tie-column and ring-beam play an important role for developing higher resistance and better deformability. And tie-column and ring-beam can effectively confined brick wall to improve the seismic performance of masonry structure. The stiffness degradation curves are similar. The stiffness degradation is modeled as a function of the effective stiffness and lateral displacement.

Abstract: The unstable failure of slope is frequent and the prevention is high difficult in the process of engineering construction. To provide reference for the prevention and control of slope landslide disaster, this paper take an engineer slope as the study background and make the strength stability analysis and evaluation of this slope. Through simulating different conditions by using the current comparatively mature limit equilibrium theory, analyzed and evaluated the stability of the slope under the conditions of precipitation, drainage and reinforced and master stability condition of this slope in the corresponding condition. The slope stability evaluation analysis results under different conditions showed that the landslide is more easily to take place under the conditions of natural state, heavy rainfall and earthquake. Slope stability improved in the drainage condition. At the same time, this paper combined the evaluation results of the analysis, putting forward prevention measures and suggestions for slope.

Abstract: The equivalent velocity spectrum as a new ground motion intensity measure (IM) characterization parameter is proposed in this paper. 44 far field ground motions and 20 near-field high-speed pulse seismic waves were used for single-degree-freedom (SDOF) nonlinear time history analysis, respectively. The correlations between five IMs and maximum deformation for SDOF at various periods and different yield coefficients were analyzed. The results show that for the structures with medium-to-long period, the correlation coefficient average value of the proposed equivalent speed and maximum deformation is more than 0.6, and maximum of those is more than 0.9. The correlation coefficient average value by using the proposed equivalent speed under far field ground motions is more than those under near field ground motions. The P-delta effect on the correlation coefficients between proposed IM for the structures with medium-to-short period is significant

Abstract: This paper firstly analyze the relationship between the fracture net pressure and the sand to fluid ratio (SOR), and the conclusion is that the high SOR could accumulate high net pressure to make the natural fractures open in natural fractured sandstone reservoir. Then relationship between the cumulative oil production and opening the natural fractures is analyzed by means of reservoir numerical simulation, and the conclusion is that the cumulative oil production increased apparently as the area of opening natural fractures increasing. Based on the analyses, a new method of optimizing fracture conductivity to elevate the stimulating reservoir volume (SRV) was formed: firstly, evaluate the stress field and calculate the critical net pressure of the natural fractures opening; secondly, determine the average proppant concentration according the relationship between the net pressure and proppant concentration; thirdly, calculate the fracture conductivity according to the proppant concentration; at last, optimize the fracture length. There are two key works: one is acquiring the accurate principal stress combining the indoor experiment and field test; the other one is acquiring accurate conductivity of proppant, and long term conductivity experiments are recommended.