WANG Lan-min , Susumu Iai , YUAN Zhong-xia
2004, 26(3):193-198.
Abstract:In this paper, the design principles, methodology and steps of International Guidelines for Aseismic Design of Port Structures are introduced. This international standard incorporates performance-based design and concerns the different seismic responses under different foundation conditions for different port structures during earthquake. These guidelines are mature in technology and flexible in practical use as well, which can be beneficial reference for professional in the field of aseismic design of port structures.
ZHANG Dong-li , TAO Xia-xin , ZHOU Zheng-hua
2004, 26(3):199-205.
Abstract:The theoiry and method of Green's function of near-field ground motion is calculating in all-around infinite space in terms of single media by analytical method and 3-D finite element difference numerical method are analysed. For the same earthquake, the source can be considered as a single point source or finite several seismic sub-sources on a finite fault plane. Green's function is caused by plus of a point source or by pluses of all sub-sources with reliable time delay. Take the Northridge earthquake in 1994, U.S.A, as an example, Green's function at three rock seismic stations (LV3, PCD, MCN) are computed and analyzed due to both methods. The results show better coherence.
SHI Yu-cheng , WANG Lan-min , LIN Xue-wen , XU Hui-ping
2004, 26(3):206-211.
Abstract:Through field investigation and testing in loess areas, the structure characteristics and natural viabration periods of different kinds of raw soil buildings are analyzed, and the major factors influencing on earthquake damage and some problems in seismic resistance of the raw soil buildings are summarized. Based on this, a method of predicting the earthquake damage of different kinds of raw soil buildings is put forward and some preliminary results are provided, too.
2004, 26(3):212-217.
Abstract:The large-scale seismicity spatial ordering pattern and the turning characteristics of postseismic activity pattern of moderate-strong earthquake are studied in Qinghai-Xizang block from 1950. The results point out that the appearance of large-scale seismicity spatial ordering before large earthquake is an important stage in the process of strong earthquake development and it can conduct the MS≥7 earthquake prediction. The breakout or turning of moderate-strong earthquake activity pattern is also an important stage in the process of postseismic activity evolvement, especially the earthquake which breaks down the pattern gives an indication of future seismic activity tendency. There is probability of reoccurring moderate-strong earthquakes or distinct events, and MS≥7 earthquake in 1~3 year in the region and adjacent areas of earthquake that breaks out the seismic activity pattern.
LIU Xu , WANG Lan-min , BAI Yao-ming
2004, 26(3):218-222.
Abstract:Based on the concepts of elastic wave velocity of skeleton and reinforced cohesion, the change of velocity resulting from the variation of soil density with the different saturation is distinguished from that caused weakened reinforced cohesion. In the condition of the same confined press and saturation, the elastic wave velocities are measured before and after soil samples are dynamically loaded, so that the elastic wave velocity changed by dynamic load is distinguished from that by soil nature characteristics. Some regular patterns of reinforced cohesion and velocity in loess under different saturation and dynamic load are discussed in a preliminary way.
2004, 26(3):223-227.
Abstract:The seismic sequence of the M5.9 Yumen earthquake on Dec. 14,2002,are relocated using the double-difference earthquake location algorithm. On this base the generating fault and mechanism are discussed.
ZHENG Wen-jun , YUAN Dao-yang , HE Wen-gui
2004, 26(3):228-233,254.
Abstract:In this paper, starting with palaeoearthquakes and historic and recent earthquakes recurrence intervals for main active fault zones in middle-eastern segment of Qilian Mt. since Holocene, by calculating the ratios of recurrence interval of strong earthquake to that of average(T/Ta), the strong earthquake recurrence probability model is established, and the model has applied to predict possibility and sites of strong earthquake. It reveals that, in this rigion the possible site where strong earthquake maybe occurs in future is on Maomaoshan-Jinqiang segment of Laohushan-Maomaoshan Fault.
MA Zhan-hu , DU Xue-bin , TAN Da-cheng , CHEN Jun-ying , ZHAO Jie , YE Qing
2004, 26(3):234-239.
Abstract:Based on the apparent electrical variations anomalies in some typical earthquake examples, the relation between apparent electrical variation anisotropy and maximum principal stress from focal mechanism is introduced, the physical mechanism of this variation is discussed. The result shows that the apparent electrical variation is related with cranny ratio v, resistivity of water filled cranny ρf and resistivity ρ0 of inherent framework,and coordinated with the earth-resistivity variation for dilatancy phase of focal region in DD model and that in loading process to rock(soil) sample.The main reasons of electrical variation are development of new-born crannies, connection of conductive channels and movement of conductive liquid near epicenter region during the late phase of strong earthquake preparation. The earth-resistivity observations in China have examined the information of this variation in deed.
HE Wen-gui , ZHENG Wen-jun , ZHAO Guang-kun , MA Er-man
2004, 26(3):240-245.
Abstract:MS6.1 & MS 5.8 Earthquakes occurred in Minle county and Shandan county, Gansu province on Oct.25, 2003. According to the field investigation, the macro-epicenter lie on the area from Yaozhaizi village of Yonggu town, Minle country to Liuzhuang village of Huocheng town, Shandan country, and the intensity of extreme seismic zone is Ⅷ. The seismogenic faults are Minle-Yongchang buried fault and Tongzihe buried fault. In the paper,the characters of local houses and structures as well as their earthquake resistance quality, and distribution of the intensities are analyzed. The relationship between ground deformations and seismogenic faults is discussed.
2004, 26(3):246-249.
Abstract:In the paper the common methods of processing microstructure image of loess from Scan Electronic Microscope (SEM) are introduced. These Methods can be used to reduce the random noise and improve the constrast of the image, so that the image can be used more efficiently for further analysis by manual work or computer-aid analysis.
2004, 26(3):250-254.
Abstract:Using the theory of elastic-plastic dynamic FEM and the Drucker-Prager yielding criterion, taking the time history of earthquake motion which fitted by the graphs of standard response spectrum on Ⅰ & Ⅲ types of site in the standard of Aseismic Design, as the earthquake input, to a typical loess landslide, in this paper the dynamic analysis and calculate on influence of earthquake motion to loess slope instability are made. The strain characteristics of loess slope in earthquake motion progress in different PGA, Tg and last times are analyzed. The result shows how the earthquake engineering characters influence on the stability of loess slope and displays the dynamic response of soil and change regularity of stress.
SHI Jin , LIU Yao-wei , GAO An-tai
2004, 26(3):255-259.
Abstract:Comparing with the deep structure of Kenya Gregory rift, the formation, evolution process and characteristics of deep structure of Tianshui area are researched. In our view, the upwelling of the deep subsurface hot fluid has greatly affected the formation and evolution process of the deep structure in the area. The results are helpful in analyzingthe mechanism of the seismogenesis.
2004, 26(3):260-264.
Abstract:Sanwei Mt. active fault is only 3 km from Mogao Grottoes in Dunhuang city, Gansu province. In this paper, based on the horizontal layered & homogeneous seismogenic fault model, the influence of ground motions generated from Sanwei Mt. fault on Mogao Grottoes under scenario earthquakes respectively with magnitude of (5.5,) 6.0 and 6.5 is simulated using the stochastic finite-fault method. It indicates that the distribution of ground motions near Sanwei Mt. fault presents the hanging wall effect of reverse fault. The calculated values of PGA are compared with those deduced from other attenuation formulas based on the data of other areas to validate the calculation result. This study has some reference to aseismatic and reinforced design in Mogao grottoes.
2004, 26(3):266-273.
Abstract:In this paper, taking Mogao Grottoes in Dunhuang, Gansu province, as the research object, the influence factors of dynamic damage for country rock of the grottoes under earthquake loading are explained. Using dynamic FEM, and based on the characteristics of ground motion caused by earthquake, the damage to the country rock and the subsidiary structures in earthquake is analyzed. The result could be used in the assessing earthquake security of historical relic grottoes and preventive measures.
HE Shao-lin , MIN Xiang-yi , HE Xin-she
2004, 26(3):274-279.
Abstract:The records of strong motion accelerograph in near field of Yumen ML4.5 earthquake on Dec.17,2002 are analyzed. After the baseline adjustment and equipment corrected, velocity time series and displacement time series and all spectrum values are calculated. In the end, the characteristics of the records in Yumen region are analyzed.
2004, 26(3):280-284.
Abstract:Using MapX provided by Maplnfo company,functions of GIS are put into VB6.0 software to build the Information Management system for Qilian Mountain active block. According to the information characters of "Qilian Mountain block" active tectonic quantitive research, an elaborate system analysis and detailed organization are made, and coded in terms of Software Engineerideas. The system using MapX4.5 to manage many kinds of maps,using Access2000 and the internal data-base to manage great number of information,to realize alternating query,editing and analysising the maps and attribute information in active tectonic reseach.
WANG Jun , WANG Lan-min , LI Lan
2004, 26(3):285-288.
Abstract:Based on dynamic triaxial liquefaction test of saturated sand and using a method combining liquefaction shear stress evaluation and earthquake response calculating, the liquefaction potential of sand in a Yangtze River Bridge site are evaluated and liquefaction level under different probability of exceedance were given.
Sopyright:China Earthquake Engineering Journal