LIU?Gao , LI?Xin-zhao , DENG?Jian-li , FU?Qing-sheng
2008, 30(1):1-5.
Abstract:A reasonable selection of mechanical parameters of rock mass for a project is very hard, because the mechanical properties and the parameters have the remarkable characteristics of spatial and temporal variability due to rock mass structure and existing environments. Both the mechanical parameters and the rock mass quality reflect the mechanical properties from different aspects and are interrelated each other, but the latter can be determined more easily than the former, so it is feasible to select the mechanical parameters of rock masses through the estimated results of rock mass quality. Based on analysis of geological conditions of rock mass, rock masses space of a project can be divided into lots of continuous cells, whose rock mass quality can be eas- ily given by such system as Q, RMR and BQ. The mechanical parameters of each cell can be calculated through the relationship between rock mass quality and mechanical parameters, for example the Hoek--Brown criterion. All the mechanical parameters of whole rock masses in a project space which reflects the spatial variability can be gotten by integrating the results of all cells. Take the underground works of a hydropower station as example, the mechanical parameters of surrounding rocks are gained using the methods mentioned as above.
DONG?Di , SANG?Xiang-guo , LIU?Rui , LI?Feng-jun
2008, 30(1):6-10.
Abstract:According to the focal mechanism the 92 groups of near field earthquake records from Europe, its neighbor regions and America are divided into 4 types. Based on the data, the effects of focal mechanism on near filed response spectrum and response spectra ratio in vertical and horizontal component of the acceleration records are analyzed. The results show that the effect of focal mechanism on response spectrum of different magnitude and different components has different features. Focal mechanism has not only some effects on the peak and peak position of response spectrum, but also on the shape of response spectrum in a certain extent.
2008, 30(1):11-16.
Abstract:A set of stagger-grid finite-difference operations with 4-order temporal accuracy and high order spatial accuracy to one-order velocity--stress P-SV wave equations is presented in heterogeneous transversely isotropic (TI) media. First using the one-order velocity--stress P-SV wave equations, the first and third order temporal derivatives of particle velocity/stress are transformed into spatial derivatives of stress/particle velocity, thus only two former time-step wave fields are needed to compute wave fields for the current time step with the 4-order temporal accuracy finite-differente approximation. Then the high-order spatial finite-difference approximation is used to improve numerical modeling precise. High consistency between the modeling vertical seismic profiles (VSP) records and the field ones demonstrates well feasibility of the present technique.
ZHANG?Yong-zhi , LUO?Ling-yan , WANG?Wei-dong
2008, 30(1):17-20.
Abstract:The theory and method of dislocation model to compute ground surface deformation is introduced. Based on the geological model for ground deformation in Xi'an city, the relationship between subsidence and 11 underground fissures is discussed and computed with dislocation model. Comparing the results of the calculation with the result obtained by leveling, it is showed that the result computed by dislocation model has the same characteristics as that obtained by leveling in space distribution. It is considered that the subsidence have relation not only with groundwater pumping and surface loading, but also with tectonics of Xi'an region.
DU?Yong-feng , SHI?Xiao-yu , CHENG?Xuan-sheng
2008, 30(1):21-26.
Abstract:Because influence of liquids, the dynamic reponse of liquid storage structures are different with other kind of structures. In this paper, taking into account the action of rebar in concrete materials, the current finite element software ADINA is used to do finite element simulation for the reinforced concrete rectangular liquid storage structures. The influences of gravity wave of the liquids surface, the stiffness of wainscots and the shape of the structures on the dynamic response with liquid-structure interaction are discussed, and the dynamic responses are also discussed in the action of unidirectional, bidirectional and three-directional coupling seismic actions. The result provides the theoretical basis for reinforced concrete rectangular liquid storage structures.
WANG?Guo-bo , YANG?Lin-de , JI?Qian-qian
2008, 30(1):27-30.
Abstract:Three-dimensional calculation model is established for the free-field shaking table model test, which is a part of the shaking table model test for typical subway station structure in soft soil in Shanghai. The model includes four aspects: the determination of calculation area, the choice of material constitutive models, the selection of dynamic boundary condition and the inputing of seismic wave. Three-dimensional fitting analysis on this model test by the calculation model is done. The results are compared with the test results and calculation results of 2-D model, and it shows a good coincide among three methods. The result indicates that the 3-D calculation model can be used to simulate the dynamic characteristic of model soil and provide a foundation to establish 3-D calculation method of seismic response for Shanghai soft soil.
2008, 30(1):31-35,45.
Abstract:The formulas for computing natural frequencies and the modes of varied section dam on layered foundation with exponential function shear modulu are derived according to shear beam theory. Furthermore, the seismic responses of the dam and the layered foundation are calculated using mode-superposition scheme. Dynamic responses of the dams and the layered foundations to earthquake are studied by the theory of random vibration, in which two cases Of power spectral intensity function for earthquake acceleration inputing at base rock are considered: the white noise spectrum and the filter white noise spectrum. The numerical calculation results show that: (1) In the case that the power spectral density of the earthquake acceleration inputing at base rock is the white noise spectrum, the maximum expected responses of the layered foundation and the dam are different from the case of the filter white noise spectrum. (2) In stationary importing and exporting, the maximum expected responses of the dam and the foundation are as same as that in the case of stationary importing and no stationary exporting. (3) In both case of the earthquake acceleration inputing at base rock and the stationary random response process, the random responses of the foundation and the dam are over-estimated .
WANG?Wan-hong , ZHANG?Hui , SU?He-jun
2008, 30(1):36-41.
Abstract:The hydrogen and oxygen stable isotopic composition and the helium isotopic composition of the hot spring water in the Northern Margin Fault Zone of Qinling are studied. Making use of heat reservoir temperature, and in connection with the local geothermal gradients, circulation depth of the hot spring waters is calculated. Meanwhile frequency of earthquakes occurring from 1900 to 1997 is counted up and analyzed. Form the point of view of weakening effect of water on fault and its wall rocks, the effect of deep circulation of the hot spring water on seismic activity is discussed. The result indicates that difference of seismic activity among each segment is related to difference of the circulation depth of hot spring water in each segment. It is suggested that a risk of strong earthquake is less possible on the Shanxi segment in which the depth is greater, but are more possible on the Gansu segment and the Qinghai segment in which the depth is smaller, and it is most possible on the Gansu segment.
ZHANG?Xiao-ping , CHEN?Ping , ZHAO?Dong , ZHOU?Tie-gang
2008, 30(1):42-45.
Abstract:The earthquake response test on shaking table for the 1/4 proportion model of a new type stone timber structure house which appeared in Kashi area of Xinjiang is designed. The testing method and the model making are introduced. Through the test the destruction shape of this kind of structure is found. The test result is analyzed and the earthquake resistance behavior of the house is preliminarily evaluated. The result shows that the structure is contented with the earthquake resistance requirement.
WANG?Ping , WANG?Lan-min , LIU?Hong-mei , DONG?Hai-feng
2008, 30(1):46-48,55.
Abstract:The mechanical principle of the 20 kN dynamic triaxial apparatu is introduced. The causes of axial friction in the device are analyzed, and some proposed solutions for the friction are explored and put into effect.
DONG?Zhi-ping , CHENG?Jian-wu , KANG?Qing-qiang , YAO?Jun
2008, 30(1):49-55.
Abstract:13 moderate-strong earthquakes occurred in Qilianshan tectonic zone [Ms≥5.3) since 1984 are analyzed. Among them 10 events (about 77%) occurred with generalized foreshocks. The predominant time interval between generalized foreshocks and mainshock is about 3 months with a predominant spatial distance in 300-400 km, and the magnitude difference is over 1. Before moderate-strong earthquakes occurred, the generalized foreshocks show the orderliness distribution along the tectonic belt, and the images in different area has certain similarity. The orderliness distribution of generalized foreshock may be taken as a short-term and imminent anomaly before the impending moderate-strong earthquake in Qilianshan tectonic zone.
LONG?Hai-ying , NIE?Xiao-hong , GAO?Guo-ying
2008, 30(1):56-61.
Abstract:The seismic belt before mid-strong earthquakes in Xinjiang Region is not clear. For this problem, the regional structure background and focal mechanism solutions of Tianshan Mountain area in Xinjiang are contrasted and analyzed with that in Sichuan and Yunnan provinces. The result shows: (1) The regional earthquake structures in Tianshan Mountain area are mainly thrust faults, while ones in Sichuan andYunnan area are mainly strike-slip faults. (2) Since 1970, the focal mechanism solutions of mid-strong earthquakes were mainly reverse and strike-slip types in Tianshan Mountain area, and most of the strike-slip events contained lean components. While ones of Ms6 strong earthquakes area were mainly the strike-slip types in Sichuan and Yunnan area, and the lean component were very small, mainly showed horizontal movement. The weak seismic belts should be applied to earthquakes which are horizontal shear movement in focal mechanism solution. Since the lean components of earthquakes were big in Tianshan Mountain area, the images of the seismic belt before mid-strong earthquakes were vague, and its significance for the earthquake forecast of mid-short term is not good.
2008, 30(1):62-65.
Abstract:The seismic sequence of Minle--Shandan Ms6.1 earthquake on Oct. 25,2003, is relocated using the dual-difference earthquake location method. The result shows that distribution of aftershocks is in NW direction, consistent with the regional tectonics. The main shock located at southeast end of the range of seismic sequence, and aftershocks are not distributed symmetrically in both side of main shock. It implies that fracturing is from the southeast to northwest and there is K a barrier at southeast of the main shock
SUN?Jia-ning , WEN?He-ping , YANG?Xiao-fang
2008, 30(1):66-70.
Abstract:The observational data of ground tilts in the range of 250 km around the epicenter, before and after Wusu Ms5. 1 Earthquake on November 23,2006 are analyzed. The result shows, since the beginning of 2005, there were evident quasi-synchronous trend anomalies in most ground tilts observational data. The main abnormal characteristics were trend E and N directions inclination quickly, and most earthquakes occurred after the anomalies ending and speeding up in the opposition, only minority of them did in the process of anomalies. Analyzing spatio-temporal distribution of the anomalies, the nearer to the epicenter, the earlier the anomalies began, and the more the number of abnormal items were, too. Comparing with previous earthquake cases, the mid-short and impeding anomalies are not obvious and most trend anomalies are still standing after the earthquake, which indicates occurring of Wusu Ms5. 1 earthquake doesn't relieve the earthquake risk in northern Tianshan Mountain area.
XIN?Hai-liang , ZHANG?Yuan-sheng , GUO?Xiao , LI?Wen
2008, 30(1):71-74.
Abstract:The Linze earthquake swarm in Gansu province in Jun. 2004 are relocated using the double-difference earthquake location genetic algorithm, the seismogenic structure is discussed with the data of geological structure. The results show that the distribution of hypocenters stretchs along the north edge of Yumushan fault in NNW direction, the focus depths of the earthquake swarm are mainly distributed in 10-25 km, and the average is 16.3 km. The seismogenic structure is the east section of the fault, whose strike is NNW, the dip direction is SW, and the dip is about 60°.
YANG?Xing-yue , WANG?Yi , WANG?Yan , LIAO?Zhen-xiang , LI?Shu-quan , ZHU?Zhen-jia
2008, 30(1):75-78.
Abstract:The gas data of No. 1 spring at Wushan station show that there were some obviously abnormal changes of outflow from 1997 to 1999 and in 2003, meanwhile, values of O2+Ar, N2 and He in the gas abnormal changed completely and synchronously with outflow. In this paper, the reason of the changes of outflow is analyzed. It is considered that the significant variety is not a dynamical nature. It is tested and verified by experiment that the influence factors on values of O2 +Ar, N2 and He in the gas in spring water are outflow, circulation time and air sneaked into the water. The relationships and change characteristics are analyzed also.
LIU?Shuang-qing , ZHU?Yuan-qing
2008, 30(1):79-87.
Abstract:The development of accumulating researches for tsunami excitation stage in theories and experiments are described, which refer to the earthquake, landslide, volcano, asteroid, manmade experiments and so on. Some new illuminations and complements for existent problems and points have not deal with are given also in the paper.
CHEN?Wen-kai , HE?Shao-lin , ZHANG?Jing-fa , ZHOU?Zhong-hong , GUO?Xiao-ning
2008, 30(1):88-93.
Abstract:In this paper the change detection methods of extracting earthquake disaster information form the Remote Sensing image at home and abroad in recent years are summarized, and they are concluded in two types: based on the feature of grain and spectrum. Meanwhile, the updated RS technology using in the earthquake disaster evaluation are introduced and the developmental tendency of RS methods is put forward.
WANG?Jian-guo , NIE?Yong-an , DONG?Hong-jun , JIANG?Chun , LI?Lian-di
2008, 30(1):94-95.
Abstract:The design throught for the database management software of earthquake routine analysis and consultation is introduced. The best database table structure and Excel templet are established in this software. The information about consultation register card, earthquake monitoring report and trends of earthqvake situation imminent tracing in the area around the capital of China can be browsed, appended, deleted, modified, saved, and printed. Anomalous frequency of every subject in the area can be calculated and drawn automatically.
Sopyright:China Earthquake Engineering Journal