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Fan W.,Changan University | Fan W.,Key Laboratory of Western Chinas Mineral Resources and Geological Engineering | Fan W.,Open Research Laboratory of Geotechnical Engineering | Du W.,China Earthquake Administration | And 2 more authors.
Journal of Earthquake Engineering and Engineering Vibration | Year: 2011

The Shaanxi areas are divided into three regions according to tectonic backgrounds and seismic damage distribution features. All their magnitude parameters are checked. Based on the statistic relations between epicentral intensity and magnitude as well as relation between sensible radius and magnitude, the near and far field seismic intensity attenuation features are represented and controlled. And then the seismic intensity attenuation relations along major axis, minor axis and mean axis are established separately. The systematic deviations of surface wave magnitude between China seismograph network and U.S.seismograph network are considered in this paper. The results of the research could be used for seismic design decision analysis. Source

Li P.,Changan University | Li P.,Open Research Laboratory of Geotechnical Engineering | Su S.-R.,Changan University | Huang Y.,Changan University | And 3 more authors.
Yantu Lixue/Rock and Soil Mechanics | Year: 2015

This paper investigates the formation mechanism and deformation law of earthquake-induced shattering-sliding collapses induced by studying the collapse at K70+340-K70+388 of S303 highway from Wolong to Balangshan in Sichuan province, using the combination of geomechanical method and the simulation of discrete element method UDEC. It is shown that: these collapses mainly occur in bedding slopes with steep joints; the seismic wave leads to a tensile-shear failure to the slope; and the tensile stress at dome of the slope is greater than that inside the slope; deformation induced by seismic force is found to be faster and greater at the upper and dome of the slope than that at the lower and interior of slope; the higher amplitude of seismic acceleration is, the greater slope dynamic response is, and the larger displacement of collapse mass. The failure process of shattering-sliding collapse can be divided into six stages, 1) rock mass damage and tensile fractures formatting under earthquake; 2) tensile fractures expansion and coalescence of weak slip plane; 3) the whole slump-mass scattered and local rocks slip; 4) local rocks fall, ejection, mass ejection and tumble; 5) rock mass fall, ejection, mass ejection and tumble; 6) slump-mass tends to be stability. Therefore, this research provides not only a new method for geological hazard analysis, but also a significant guide to disaster prevention and mitigation in earthquake region. © 2015, Academia Sinica. All right reserved. Source

Deng L.-S.,Changan University | Fan W.,Changan University | Fan W.,Key Laboratory of Western Chinas Mineral Resources and Geological Engineering | Fan W.,Open Research Laboratory of Geotechnical Engineering | And 2 more authors.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2010

Based on the distribution and movement of ground fissures and the condition of No. 2 metro tunnel in Xi'an, a geological model is established. Through the numerical analysis of finite element model, the protection range of the metro tunnel crossing ground fissures and its most dangerous section are confirmed by analyzing its deformation and stress states, and then, the distribution characteristics of surrounding rock pressure are studied so as to provide a basis for simplification of the model to calculate the stress of the metro tunnel crossing ground fissure. The results show that the main protection range of deformation and stress of the metro tunnel is from the location at the upper wall 40 m to that at the lower wall 30 m away from the fissure, that the most dangerous section is mainly distributed at the place of the ground fissure with a distance of 15~20 m at both sides, and that the structure in the range of 15 m away from the fissure at both sides suffers the maximum shear stress. The vertical pressure above the metro tunnel at the upper wall near the fissure is greater than that at the bottom, and the latter may be ignored. Therefore, the section of the metro tunnel crossing the fissure should be regarded as a beam which is sustained at the two sides of the subsiding area, and the vertical pressure of wall rock used to confirm the flexural torque produced by the activity of ground fissures should be calculated by the theory of stress transfer. Source

Zhang C.,Changan University | Zhang C.,Open Research Laboratory of Geotechnical Engineering | Lei X.,Chinese Research Institute of Highway | Li T.,Changan University | Li P.,Changan University
Advanced Materials Research | Year: 2011

On the base of the equilibrium of the whole force equilibrium, the whole moment equilibrium of the slope, and the force equilibrium of the differential column, this paper provides a general form of the 3D limit equilibrium which includes three equations. Through these equations and each assumption of the classical methods, their analytic forms can be gotten. Thus, not only the computation quantities of the classical method can be decreased greatly, but also the programming of them become very easy, and the computation efficiency also can be developed. At last, through the example in Zhang Xing's paper and the analytic forms of the classical methods, this paper analyzes the effect of the sliding body width, the shearing strength parameters and the shearing force direction on the safety factor. © (2011) Trans Tech Publications, Switzerland. Source

Chen W.,Changan University | Chen W.,Key Laboratory of Western Chinas Mineral Resource and Geological Engineering | Chen W.,Open Research Laboratory of Geotechnical Engineering | Zhao F.,Changan University | And 2 more authors.
Applied Mechanics and Materials | Year: 2013

A linear viscoelastic plastic creep model of mica-quartzose schist is established by using the method of establishing combined-linear-component model based on triaxial creep test. The micro-structural changes of mica-quartzose schist during triaxial creep process are observed by using the scanning electron microscope test, based on that, the relation of macro-stress and macro-strain with porosity and damage variable are established through statistical damage theory and simplified mechanical model respectively, the creep damage variable is obtained by further derivation on the basis of above study. The creep damage variable is simplified according to the whole creep process curve, substitutes the simplified creep damage to the estabilished linear viscoelastic plastic creep model of mica-quartzose schist, considering the change of modulus and viscosity during creep process, a viscoelastic plastic damage model of mica-quartzose schist is established. The model parameters are got by segment fitting, the good consistency of the test curves and the fitted curves shows the right and reasonable of the creep model, it also shows that the model can well describe the nonlinear accelerated creep stage. Sensitivity analysis shows that parameter m has greater influence on the accelerated creep deformation than parameter a. © (2013) Trans Tech Publications, Switzerland. Source

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