Applied Mechanics and Materials Vols. 256-259

Abstract: The Smoothed Particle Hydrodynamics (SPH) method is a mesh-free Lagrangian approach which is capable of tracking the large deformations of the free surface with good accuracy. A three-dimensional SPH model was proposed to simulate the wave–structure interaction (WSI), in which a weakly compressible SPH model was introduced to investigate the wave breaking and coastal structure. To validate the SPH numerical model, three different types of wave breaking, namely, spilling, plunging and surging breaking were successfully simulated. The computations were compared with the experimental data and a good agreement was observed. The hydrodynamics model of interaction between wave and structure was established according to Navier-Stokes equations in SPH style. And the model was used in simulating the interaction between wave and a series of new type breakwaters. It is proven to be a promising tool and able to provide reliable prediction on the wave-structure interaction in coastal engineering.

Abstract: A sequential assimilation method is applied to improve the accuracy of wave simulations in the South China Sea. Typhoon Nesat was chosen to be used for the numerical experiment. The assimilation is based on Optimal Interpolation(OI) which can minimize the Root-Mean-Square error in the analysis. Using the method of OI, wave height and mean period data observed by three buoys have been assimilated into the third generation ocean wave model(SWAN). The results show that the assimilation can correct the difference between the wave model and observations, and the result of significant wave height is superior to that of mean period.

Abstract: 0# diesel is common petroleum hydrocarbon pollutant of sea and marine organisms. One goal of this study was to assess the chronic toxic effect of water-accommodated fractions（WAFS）of 0# diesel oil on Splox gene of Strongylocentyotus intermedius by PCR-SSCP. The experiment was carried out with three concentrations (5mg/L, 20mg/L and 50mg/l). The results show that with the increase of exposure concentration and time, the mutation probability of the sea urchin increased. In the four primers, single base mutation took place in coding region of the 41 of Primer A-1, with the conversion of A-G, where amino acid changed from lysine into arginine.

Abstract: The mechanism of geogrid reinforcement in an embankment widening project was investigated in this study using numerical analysis. It was found that the geogrid reinforcement mainly affects the new embankment by decreasing settlement slightly and restraining the horizontal outward displacement effectively. This effect of geogrid reinforcement on embankment deformations is due to the stress redistribution in the new embankment and in the subsoil caused by geogrid reinforcement. The inclusion of geogrid reinforcement produces a small decrease in vertical stress in the new embankment and leads to a relatively larger increase in horizontal stress in the subsoil, thereby decreasing the shear stress of the subsoil. The effect of geogrid reinforcement on the new embankment and subsoil increases with the increasing geogrid layer number.

Abstract: Total 163 survey points distributed in 104 liquefied and non-liquefied sites were selected in the Wenchuan earthquake liquefaction database, where 50 survey points were from intensity VI region. Borehole data show that pure sandy layers could hardly be identified in Wenchuan earthquake affected areas, instead gravel soil layers mingled with sand silty or pebble prevalently exist. Songbai village which suffered severe liquefaction was chosen for case study in this paper. Through MASW and high density electrical method testing, three soil layers can be distinguished from the testing cross section. The discontinuity of resistivity of the first layer by the high density electrical method indicates the location of sand ejection. The grain size distribution curves of sand ejecta were different from drilling soil samples, which explanation need further investigation.

Abstract: Through series of dynamic triaxial tests, the relationships of soil deformations under irregular seismic loading and fixed-number constant amplitude loading are analyzed. The effect of loading amplitudes on the relationships is presented. The results shows: (1) soil deformation under irregular seismic loading obviously differs from that under constant amplitude sinusoidal loading, and the strain history is mainly controlled by the performance of ground motion; (2) if 20 cycles of constant amplitude loading is employed instead of irregular seismic loading to correct residual deformation under real seismic loading, loading amplitudes have no effect on soil deformation under irregular waves and fix-number waves.

Abstract: According to the force condition of wire mesh frame wallboard under seismic action, finite element program is used to conduct the deformation simulation analysis of 12 test pieces under different working conditions, obtaining the influencing factors that affect the deformation of wire mesh frame wallboard under vertical seismic action, which offers theoretical foundation for the design of wire mesh frame wallboard.

Abstract: The earthquake responses of short span structures are usually obtained by using uniform excitations. Wave passage effects are often artificially neglected for short span structures. In this paper, a high-rise steel residence structure of 18-story is adopted to study the earthquake responses of high-rise steel structures to wave passage excitations and uniform excitations by using the software Midas/GEN. Two groups of earthquake acceleration records are chosen respectively from sites of hard soil and soft soil. Comparisons of the shear forces and the bending moments under uniform excitations and wave passage excitations shown that wave passage effects shouldn’t be neglected in the earthquake response analyses even for short span structures.

Abstract: In this paper a skyscrapers frame-core wall structure as an example in Kun Ming, using two independent software, SATWE and ETABS, analyzed the dynamic characteristics and dynamic response of structures with earthquake in linear elastic phase and the elastic-plastic phase respectively, so that could evaluate rationality of the design of the structure as a whole and seismic performance superior or not, and it could provide an idea for audit drawing or proofread their own.

Abstract: Earthquake damage prediction is a fundamental topic for working out the urban earthquake disaster prevention planning, improving earthquake emergency plans and preparedness, establishing seismic fortification criterion, and achieving the goal of earthquake preparedness and disaster reduction. It’s significant to carry out urban seismic damage prediction. To display and apply the results of damage prediction more scientifically, intuitively, integrally, objectively and fully, the technical methods and ideas of using virtual simulation technology are proposed and studied, and the system requirements, functional design and structural framework are also described in this paper. These studies will provide effective technical support for the damage prediction to serve the urban disaster reduction, improvement of people's awareness of disaster prevention and refuge and so on, and have good application prospects.