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He H.,Changan University | He H.,Key Laboratory of Western Mineral Resources and Geological Engineering | Qu C.,Changan University
Disaster Advances | Year: 2014

Analyzing on highway landslide hazard evaluation characteristics and existing problems of evaluation method, combining with information entropy theory and uncertainty measurement theory, highway landslide hazard evaluation model was put forward on the basis of information entropy and unascertained measure theory. Information entropy was used for the reduction of highway landslide hazard evaluation index system, the removal of redundant index; highway landslide hazard was carried through evaluation on the basis of uncertainty measure theory. At the same time, combined with 15 landslides in Yingxiu-Wolong of S303 line, the validity of the model was verified. Research results show that the method uses information entropy to reduce evaluation index, evaluation accuracy is not reduced but the amount of calculation is reduced. Landslide hazard evaluation provides significance for the future. Source


Hujun H.,Changan University | Hujun H.,Key Laboratory of Western Mineral Resources and Geological Engineering | Shengrui S.,Changan University | Ying Z.,Changan University | Peng L.,Changan University
Disaster Advances | Year: 2013

Two-dimensional finite element model of Longmenshan area was built on the basis of depth study on geological structure conditions and of rock mechanical properties in Longmenshan area. Tectonic stress field and variation process of Longmenshan fault belt were inversed before the earthquake, in the earthquake and after the earthquake. The results show that: (1) the direction of maximum main stress in the study area has regionalization, according to stress direction differences before the earthquake, in the earthquake and after the earthquake and can be divided into the southwest region of Houshan fault, the middle section of Houshan fault, the region near Yingxiu of central fault, Xiaoyudong area between central fault and Qianshan fault, the region between Qingping village of central fault and Guangming village of Houshan fault, the region between central fracture and Houshan fault in the west of Beichuan. (2) there are local shear stress concentration areas in Longmenshan fault zone before the earthquake and in the earthquake, especially near Yingxiu but after the earthquake, shear stress distribution is more uniform. Shear stress concentration zone of Longmenshan central fault presents the migration at northeast, the most prominent near Yingxiu. Source


Zhao H.,Changan University | Zhao H.,Key Laboratory of Western Mineral Resources and Geological Engineering | Dang B.,Changan University | Dang B.,Key Laboratory of Western Mineral Resources and Geological Engineering | And 4 more authors.
Geological Bulletin of China | Year: 2014

The relatively high permeability reservoir is the exploration and development direction of the low permeability oilfield. A new oil-bearing layer, i.e., Chang 101 oil layer of Triassic Yanchang Formation, was found in Zhidan area of Ordos Basin in 2007. It has been proved by practice that the study area has a good exploration prospect. Based on core observation and all kinds of analytical means, such as cast thin sections, physical properties, X-ray diffraction, SEM and capillary pressure curve, the authors studied the characteristics of the relatively high permeability reservoir and its control factors. The results show that the relatively high permeability reservoirs are made of medium-coarse or medium feldspar sandstones which have relatively high compositional maturity. The cements are mainly chlorite film and laumontite, and the diagenesis mainly finds expression in secondary dissolution. Pore types are solution opening and inter-granular opening. Feldspar solution opening and laumontite solution opening constitute the main types of solution opening. The factors controlling the relatively high permeability reservoir are delta distributary channel microfacies which control the reservoir distribution and its primary material. The chlorite film is favorable for the preservation of primary inter-granular pore, whereas the secondary dissolution of feldspar and laumontite seems to be the key to improving the reservoir property. Source


He H.,Changan University | He H.,Key Laboratory of Western Mineral Resources and Geological Engineering | Su S.,Changan University | Su S.,Key Laboratory of Western Mineral Resources and Geological Engineering | And 2 more authors.
Disaster Advances | Year: 2012

Analyzing activity evaluation significance of active faults, according to activity evaluation uncertainties of active fault, this paper studies activity index condition of active fault, fully considers various factors, uses information entropy and unascertained measure theory, builds rank-evaluating and order- arranging model of active faults activity. Starting from practical geologic condition, 5 factors that influence activity of faults are taken into account and uncertainty measure function is obtained based on the in-situ data. The uncertainty problems in activity evaluation of active faults are solved by qualitative analysis and quantitative analysis respectively. Information entropy theory is used to calculate the index weight of factors, credible degree recognition criteria is used to judge activity rank of active faults, and the activity is arranged in the order. This model is employed to evaluate 4 active faults in Xi'an. The results show that uncertainty measure method is reasonable and can provide certain reference significance for activity evaluation of active faults in the future. Source


Su S.,Changan University | Su S.,Key Laboratory of Western Mineral Resources and Geological Engineering | He H.,Changan University | He H.,Key Laboratory of Western Mineral Resources and Geological Engineering | And 3 more authors.
Disaster Advances | Year: 2012

According to the investigation of typical earthquake surface rupture in main street of Xiaoyudong town, this paper studies the stress distribution state near the surface rupture of earthquake in main street of Xiaoyudong town using two-dimensional finite element numerical simulation software of MIDAS/GTS, thereby fits the actual impact range of seismic deformation zone to buildings damage". The results show that the site is overall upward under earthquake, both displacement and stress are greater in hanging wall of fault than in fault footwall and top-down change law of displacement is reverse with stress change. After earthquake, hanging wall of fault deflects to footwall fault, the deflection results in strong tensile stress in hanging wall of fault, thereby easily generates tension crack in houses and ground. The maximum principal stress vector direction is some oblique or some vertical. On the ground, the maximum principal stress vector is parallel to the ground and the maximum principal stress and shear stress appear the maximum value near fault. Source

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