Applied Mechanics and Materials Vols. 477-478

Abstract: The stress drop during a earthquake is deal with by many papers, but has not been estimated very well yet at present. In order to study its influence on synthesized motion, the motions at two rock sites where records were obtained during the Wenchuan earthquake are synthesized by a hybrid source model from two stress drop values, 30 bar and 85 bars respectively. The result shows that the acceleration time histories, response spectra and mean peak values of motions from 85 bar are comparable to the records, but those of motions from 30 bar are much smaller than the records. It means that the way to inverse the regional parameters simultaneously from regional small quake records is acceptable.

Abstract: The ground motions at two rock stations where motions were recorded during the great Wenchuan earthquae are randomly synthsized for 10 times. The mean response spectrum and mean PGA of each synthesis and the general mean spectrum and PGA after each synthesis are calculated. The result shows the fact that the general mean spectrum after 10 syntheses, and the general mean PGA could be improved just a little. It means that it is not necessary to synthsize ground motion many times for an engineering site in practice, if the mean spectrum and PG are taken from the syntheses by 30 source models.

Abstract: On July 22, 2013, an Ms6.6 earthquake occurred in Minxian-Zhangxian, Gansu Province, China, which caused serious damages. Based on Okada's elastic half-space model, we used thrust, strike-slip and thrust-strike as receiver faults respectively to calculate Coulomb stress changes (ΔCFS) of three moderate-strong earthquakes. The results show that the thrust and thrust-strike models are better. More than 90% of aftershocks located in NWW and SEE ,the stress increased areas, which is consistent with strike of Lintan-Tanchang fault (LTF). Therefore, Dieterich’s rate-friction law is used to simulate ΔCFS caused by the activity of the temporal evolution. It shows the seismicity of Minxian and adjacent area is the most frequent and that the distribution of earthquakes is perpendicular to the strike of LTF. The activity degrees vary for the LTF. Tanchang is the strongest, followed by the middle and western, and Minxian is the weakest. Except Minxian, the activities of all areas are above the background seismicity during 300 years and it will be up to the background for 400 years.

Abstract: Data recorded by borehole arrays with sensors installed at surface and geologic layers provide critical information for studies of local site amplification effects. The stations of KiK-net strong-motion seismograph network contain detailed information about the condition of site soil, we can judge the site categories according to these information. The stations have collected a large number of seismic records since operated. These seismic records can be downloaded free from the website of KiK-net if you are the register of the website. This paper select 30 sites-type III and 9 sites-type IV from KiK-net strong-motion seismograph network according to the China code for seismic design of buildings (GB50011-2010), and calculate Amplification Coefficient and Site Coefficient by seismic records from the selected stations. Using above information, this paper give their probability distribution and mean value.

Abstract: Seismic inversion includes different methods. Acoustic impedance inversion is an ordinary method to find reservoir in oil and gas exploration, but in some area the Acoustic impedance inversion is not effective on different geologic setting. In this paper we found the Gamma Ray is effective on distinguish the sand and shale bed by using P-wave and Gamma Ray crossplot analysis. The final Gamma Ray seismic inversion results show that Gamma Ray seismic inversion can improve the vertical resolution. A satisfactory inversion effect is obtained in HM area.

Abstract: The structural composition and construction of websteel structure system were introduced. And on this basis the building technique of finite element integrity model was provided with Ansys software. The horizontal displacement and the acceleration of structure under seismic load were analyzed. The result was shown that the inter-storey and top horizontal displacement and the acceleration were smaller than the code values of the tow-storey websteel building under earthquake.

Abstract: After an introduction of the involve type of panelfrictional in-filled panel (FIP for short), a finite element model has been built to research on the seismic behavior of RC frame with different panels (FIP and traditional in-filled panel, TIP for short). The Taft wave was chosen for further seismic analysis. Results show that the layout schemes of FIP have significant influence to the story drift and slight influence to the acceleration of RC frame. Compared with the TIP, the FIP have almost no stiffening and strengthening effect to the frame, and showed a certain degree of energy dissipation effects, which indicate a good applicability in engineering.

Abstract: This paper divided the seismic performance of RC Components into five levels: integrity, slight damage, slight ~ moderate damage and serious damage, which were defined based on material damage. Physical and mechanical description of RC components in each performance level was given, which can be used as the basis of performance-based evaluation of concrete components in microscopic model and the basis of research on deformation index limits in macro components.

Abstract: On February 22, 2011 a M_W 6.2 earthquake struck Christchurch in New Zealand, which is the first time that liquefaction acts as the main cause of damage since there is survey record of historical earthquakes. On the basis of field investigation and in-situ test data, domestic and foreign liquefaction evaluation methods based on CPT including Chinese code, Robertson and Olsen methods are examined and their applicability and reliability are assessed. Analysis shows that the method adopted in Chinese code is more dangerous, whose success rates of liquefaction and non-liquefaction evaluation are 70% and 94%.The other two methods abroad are severely conservative, for the success rates of liquefaction and non-liquefaction evaluation of Robertson method are 100% and 40%, and Olsen method 100% and 11% respectively. Liquefaction evaluation methods need further research to be improved.

Abstract: To assess liquefaction degree in the south region of Tangshan city, totally 65 boreholes are collected and the establishment of drilling graphics database and attribute database are completed on ArcGIS.Then the potential of liquefaction values are given by a multi-factor regression method, seven factors and four factors for different precisions respectively. According to these drilling data, liquefaction condition for each borehole is discriminated, and the liquefaction condition of the unknown area is speculated by Kriging interpolation method, then the liquefaction zoning map of south of Tangshan and its southern region is presented based on ArcGIS.