Applied Mechanics and Materials Vols. 166-169

Abstract: Guojuanyan gully, which lies in the center of earthquake-stricken area Dujiangyan city, is a viscous debris flow gully post Wenchuan strong earthquake. This paper made a deep analysis of the debris flow formation condition on the base of Guojuanyan valley and debris flow characteristics firstly, then conducted a calculation on the debris flow kinetic parameters, last parsed the development tendency of the Guojuanyan gully in the future and posed prevention measures based on its dangerous and objects which need to protect.

Abstract: The landslides caused serious casualties and property losses in Wenchuan earthquake, China. According to the survey data of the landslides, the landslide lithology, contribution rate of lithology, height difference and volume of the landslides were studied. The results indicated that the 13 lithologies had the larger relationship with seismic landslide development. In these lithologies, The Phyllite (Ph) had the greatest contribution rate on the landslide number, landslide area and landslide volume. The Stone soil (Ss) had the largest volume of landslide on unit landslide area. Metamorphic sandstone (Ms), Gravelly soil (Gs), Sandstone (Sa), Phyllite (Ph), Limestone (Li) had the greater combined effects on the landslide development.

Abstract: Due to frequent earthquakes in recent years, the seismic safety of large storage tank is very important. In this paper, seismic response of large liquid storage tanks is analyzed. A model for liquid storage tank is established firstly. By modality analysis, dynamic behavior of large storage tank is obtained. After the model is excitated by seismic, seismic responses are obtained. The conclusions show that, without considering liquid-solid coupling, "elephant foot" buckling phenomenon doesn’t appear. This study provides reference for seismic design and seismic performance study of large storage tank.

Abstract: By means of survey and study, various submarine seismic records were identified in the marine facies strata from Sinian Period to Ordovician Period in Tancheng-Lujiang seismic fault zone and its vicinity. These submarine seismic records are divided into two classes. According to the mode of seismic action, every class of submarine seismic records is divided into three to four types. On the basis of classification, this paper studied and summarized seismic destructive effects to the submarine rock and soil layers and diagrammatized mechanism and process of seismic destructive effects. Seismic destructive effects to soft sedimentary soil strata mainly include seismic vibratory liquefaction, vibratory thixotropic effect, seismic fold deformation, sliding deformation, tensile deformation and combined action of shaking and weight. Seismic destructive effects to submarine soil strata of semi-consolidated to un-completely consolidated sediments mainly include syn-sedimentary fault effect, crack and smashing effect, filling effect of seismic crack, etc.

Abstract: Taking steam-turbine generator foundation of 1251 MW as the example in this paper, 1:8 test model is designed. Pseudo-dynamic test is carried out under intensity 7 frequently and rarely earthquake. And earthquake response characteristics of the foundation are researched. The test result shows that the foundation has the better emergency capecity. Even if design reference period is changed into 60 years from 50 years, the foundation will satisfy the requirements of seismic design standard.

Abstract: Rubber bearing base-isolation is well-developed vibration reduction technique, and is applied in practical engineering broadly. But displacement of vibration isolating layer is large, so lead plug rubber bearing is used. It is passive control device; therefore its optimal central extent is narrow. That is isolating layer is optical in several defined kind and magnitude of earthquake waves, in the way controlled displacement and acceleration of superstructure is ideal. Magnetorheological damper has good smart performances- broad controlled band, fast response and demand a little energy. In this paper smart base isolation system, which is combined with rubber bearing and MR damper, is applied to structural vibration control, and have numerical simulation of structure employing LRB isolation and smart isolation in different kind and magnitude of earthquake waves. The result indicates smart base-isolation with MR damper can supply optimal control to these different earthquake waves, so is a good supplement and perfection for former isolation technique.

Abstract: To eliminate the drifting in recordings from Ms8.0 Wenchuan earthquake, a modified two segments baseline correction method is brought up and systematic acceptance standard is presented. The method is applied to recordings from Qingping station and Bajiao station, which are closest stations to surface rupture traces. The effect of baseline correction on acceleration time history, Fourier amplitude spectrum and 5% damped relative displacement response spectrum is analyzed.

Abstract: Earthquakes cause severe damage to structures and economic losses recently, based on which investigations are carried out on village buildings in Wenzou. Investigation results show that cavity wall structures are the most widely used by village buildings. So a typical cavity wall structure is selected for analyses in this paper. The typical structure is simulated using Sap2000. The structure was analyzed with and without structural columns and ring beams. Analyses results show that the prototype structure is inadequate to resist earthquake load. Structural columns and ring beams can enhance its seismic performance and provide it adequate seismic performance. So it is necessary to enhance village structures with structural measures.

Abstract: The cellullar seismology method has been proposed in this paper. Using this method, we select percentage of map area (33%) at first, then determine radius of trap region, and finally estimate probability of 'after' earthquake in the trap region. In four regions of different tectonic environments and seismic activity in China, we estimate probability of 'after' earthquake in the trap region respectively. Our results indicate that probability of 'after' earthquake in the trap region is greater than percentage of map area, and that future earthquakes occur frequently where past earthquakes have occurred. Therefore, it is feasible that using seismicity prediction to delineate potential locations of future earthquakes which varies for regions with different tectonic environments.

Abstract: The traditional limit equilibrium method in the analysis of slope stability not only exists some subjective empirical hypothesis that can not meet the equilibrium of force and moment, but also ignores the effects of internal stress and strain on the slope stability. Furthermore, in the stability of the slope evaluation, limit equilibrium method relies too much on experience when hypothesizing the slope slip surface. So that it makes deviation on slope analysis and stability evaluation. This paper is based on simplified Bishop method used to establish the model of slope stability analysis. And it used genetic algorithms to solve the minimum safety factor and the most dangerous slip surface of slope. It was the arithmetic which simulates organisms genetic evolutionary process and it avoided the traditional methods falling into the local extreme value point easily and error propagation leading to convergence. The algorithm had advantages of higher accuracy, quick convergence and applicability. It showed that the genetic algorithm is accurate and reliable in the analysis of slope stability.