Since 1949, Chinese scientists have successfully predicted occurrence of many major earthquakes, such as the Haicheng MT. 3 event in 1975 and the Asian Game Village shock of 1990. In recent 20 years, however, some sei...Since 1949, Chinese scientists have successfully predicted occurrence of many major earthquakes, such as the Haicheng MT. 3 event in 1975 and the Asian Game Village shock of 1990. In recent 20 years, however, some seis-mologists abroad have taken a disappointed and pessimistic view to earthquake prediction because of several failures. They suggest that the efforts should turn toward other fields, such as identification of building＇ s earthquake-proof capability, enhancement of house strength, and development of precise observational systems which will facilitate fast loca- ting of future major temblors and emergent relief on site. Such a pessimistic feeling has also influenced some Chinese researchers of the seismological community who attempted to give up efforts for earthquake prediction. Meanwhile other scientific workers are insisting in experiments and practices in this field and achieved some inspiring results. In this paper, we present several representative cases to illustrate that earthquakes are predictable under some conditions.展开更多
Presented in this paper are the results of experimental study and analysis of the subsidence characteristics obtained from soil samples with different contents of clay particles though laboratory dynamic triaxial test...Presented in this paper are the results of experimental study and analysis of the subsidence characteristics obtained from soil samples with different contents of clay particles though laboratory dynamic triaxial test, Laser particle size analysis, chemical analysis and electronic microscope scanning. By comparison of the obtained data, the following conclusions are drawn out:(1)The stability of the loess varies with different content of clay; (2) The relation between the dynamic shear strength and the clay particles is not monotonous, but parabolic; (3) In the same consolidation ratio, the clayey loess is the weakest subsidence-resistant when the clay particle content is between 16%～17%.展开更多
The seismic resistance properties of the structures of short-limbed walls (SLW) were explored by horizontal cyclic loading experiments on 6 SLW specimens including 3 flanged and 3 non-flanged. The ratios of the depth ...The seismic resistance properties of the structures of short-limbed walls (SLW) were explored by horizontal cyclic loading experiments on 6 SLW specimens including 3 flanged and 3 non-flanged. The ratios of the depth to the width of the 3 specimens in each group were 5, 6.5 and 8, respectively. For non-flanged SLW structures with a small depth-to-width ratio, longitudinal bars in the limb yield first;and for those with a large depth-to-width ratio, stirrups in a linking beam yield first. For a structure with different depth-to-width ratio varying from 5 to 8, the failure mode is different. Correspondingly, different calculation model should be used in the design and engineering of the structure. For flanged SLW structures with whatever depth-to-width ratio, longitudinal bars in a flange or limb yield first. The SLW structures with a depth-to-width ratio of 6.5 exhibit the best comprehensive seismic resistant property and flanged walls have a better ductility than non-flanged ones.展开更多
This paper describes briefly the recent advances and achievements of the research projects conducted by the Institute of Engineering Mechanics (IEM) in the period of the Ninth Five-Year Plan (1995～2000) with the supp...This paper describes briefly the recent advances and achievements of the research projects conducted by the Institute of Engineering Mechanics (IEM) in the period of the Ninth Five-Year Plan (1995～2000) with the support of the China Seismological Bureau (CSB). These projects are related with key problems in the field of earthquake engineering. They are: development of the methods for determining earthquake resistant design load level, study on mechanisms of earthquake damage to buildings; development of new technology of base isolation, and study on earthquake damage prediction and seismic loss assessment methods. Through these studies, quite a number of problems have been solved and some of them have been applied in earthquake engineering design and practice.展开更多
Research on the seismic vulnerability of building structures is very important for the work of earthquake disaster preparedness and mitigation. On the basis of the related studies over a long time, this paper provides...Research on the seismic vulnerability of building structures is very important for the work of earthquake disaster preparedness and mitigation. On the basis of the related studies over a long time, this paper provides several seismic vulnerability matrices of building structure in different regions of Sichuan Province. Poor anti-seismic capability is one of the factors resulting in the earthquake disasters in the past. We can reduce economic losses caused by earthquake through improving the anti-seismic and prevention level of building structures in Sichuan Province.展开更多
Additional displacement of the building foundations over old goaf are prone to happen under the addi- tional loads induced by new buildings, weakening-rock mass by mining and seismic actions, which will cause serious ...Additional displacement of the building foundations over old goaf are prone to happen under the addi- tional loads induced by new buildings, weakening-rock mass by mining and seismic actions, which will cause serious damage to the buildings. In order to analyze the safety of the building foundations safety over the old goaf. the structure characteristics of the strata over the old goaf was investigated and the instability conditions of overhanging rocks upon old goaf were also analyzed in this paper. The results indicate that the stability of overhanging rocks is remarkably decreased by the interactions of mining fractures, earthquake force and building load, in addition, the settlement of the foundations over old goal is increased by the instability of overhanging rocks. According to the location of a new power plant in Yima Mine and its ambient conditions, we defined the influence scope of old goal via resistivity tomography. Based on the seismic parameters of the construction site, a numerical FLAC3d model of the building foundation under the seismic actions and building load was developed. The numerical results are obtained as follows： the foundation of the main power house meets the requirement of 6° seismic fortification intensity： however, under 7° seismic fortification intensity, the maximum differential settlement of foundation between the neighboring pillars is close to the maximum allowable value, while the seismic fortification intensity reaches 8°, but the safety requirements will not be satisfied.展开更多
文摘Since 1949, Chinese scientists have successfully predicted occurrence of many major earthquakes, such as the Haicheng MT. 3 event in 1975 and the Asian Game Village shock of 1990. In recent 20 years, however, some seis-mologists abroad have taken a disappointed and pessimistic view to earthquake prediction because of several failures. They suggest that the efforts should turn toward other fields, such as identification of building＇ s earthquake-proof capability, enhancement of house strength, and development of precise observational systems which will facilitate fast loca- ting of future major temblors and emergent relief on site. Such a pessimistic feeling has also influenced some Chinese researchers of the seismological community who attempted to give up efforts for earthquake prediction. Meanwhile other scientific workers are insisting in experiments and practices in this field and achieved some inspiring results. In this paper, we present several representative cases to illustrate that earthquakes are predictable under some conditions.
基金This research was funded by the Special Social Commonweal Research Programs of the Ministry of Science and Technology of China (Grant No2004DIB3J130) Contribution No:LC20070049 for Lanzhou Institute of Seismology,CEA
文摘Presented in this paper are the results of experimental study and analysis of the subsidence characteristics obtained from soil samples with different contents of clay particles though laboratory dynamic triaxial test, Laser particle size analysis, chemical analysis and electronic microscope scanning. By comparison of the obtained data, the following conclusions are drawn out:(1)The stability of the loess varies with different content of clay; (2) The relation between the dynamic shear strength and the clay particles is not monotonous, but parabolic; (3) In the same consolidation ratio, the clayey loess is the weakest subsidence-resistant when the clay particle content is between 16%～17%.
基金the Key Scientific and Technological Reseach Program of Wuhan Construction Committee (No. 200412033).
文摘The seismic resistance properties of the structures of short-limbed walls (SLW) were explored by horizontal cyclic loading experiments on 6 SLW specimens including 3 flanged and 3 non-flanged. The ratios of the depth to the width of the 3 specimens in each group were 5, 6.5 and 8, respectively. For non-flanged SLW structures with a small depth-to-width ratio, longitudinal bars in the limb yield first;and for those with a large depth-to-width ratio, stirrups in a linking beam yield first. For a structure with different depth-to-width ratio varying from 5 to 8, the failure mode is different. Correspondingly, different calculation model should be used in the design and engineering of the structure. For flanged SLW structures with whatever depth-to-width ratio, longitudinal bars in a flange or limb yield first. The SLW structures with a depth-to-width ratio of 6.5 exhibit the best comprehensive seismic resistant property and flanged walls have a better ductility than non-flanged ones.
文摘This paper describes briefly the recent advances and achievements of the research projects conducted by the Institute of Engineering Mechanics (IEM) in the period of the Ninth Five-Year Plan (1995～2000) with the support of the China Seismological Bureau (CSB). These projects are related with key problems in the field of earthquake engineering. They are: development of the methods for determining earthquake resistant design load level, study on mechanisms of earthquake damage to buildings; development of new technology of base isolation, and study on earthquake damage prediction and seismic loss assessment methods. Through these studies, quite a number of problems have been solved and some of them have been applied in earthquake engineering design and practice.
文摘Research on the seismic vulnerability of building structures is very important for the work of earthquake disaster preparedness and mitigation. On the basis of the related studies over a long time, this paper provides several seismic vulnerability matrices of building structure in different regions of Sichuan Province. Poor anti-seismic capability is one of the factors resulting in the earthquake disasters in the past. We can reduce economic losses caused by earthquake through improving the anti-seismic and prevention level of building structures in Sichuan Province.
基金the Funds of the State Key Development Program for Basic Research of China (Nos. 2013CB227900, 2010CB226800)the National Natural Science Foundation of China (Nos. 51108161, 51374201)+2 种基金the Open Laboratory Foundation for Deep Mine Construction of Henan Province of China (No. 2011KF-09)the Doctor Foundation in Henan Polytechnic University of China (No. Q2013-065)the Key Program for Science and Technology Research of Henan Province of China (Nos. 14A560002, 14B560021).
文摘Additional displacement of the building foundations over old goaf are prone to happen under the addi- tional loads induced by new buildings, weakening-rock mass by mining and seismic actions, which will cause serious damage to the buildings. In order to analyze the safety of the building foundations safety over the old goaf. the structure characteristics of the strata over the old goaf was investigated and the instability conditions of overhanging rocks upon old goaf were also analyzed in this paper. The results indicate that the stability of overhanging rocks is remarkably decreased by the interactions of mining fractures, earthquake force and building load, in addition, the settlement of the foundations over old goal is increased by the instability of overhanging rocks. According to the location of a new power plant in Yima Mine and its ambient conditions, we defined the influence scope of old goal via resistivity tomography. Based on the seismic parameters of the construction site, a numerical FLAC3d model of the building foundation under the seismic actions and building load was developed. The numerical results are obtained as follows： the foundation of the main power house meets the requirement of 6° seismic fortification intensity： however, under 7° seismic fortification intensity, the maximum differential settlement of foundation between the neighboring pillars is close to the maximum allowable value, while the seismic fortification intensity reaches 8°, but the safety requirements will not be satisfied.
