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Xu J.,Chang'an University | Ma R.,Chang'an University | Ma R.,Key Laboratory of Western Mineral Resources and Geological Engineering | Peng J.,Chang'an University | And 4 more authors.
Journal of Natural Disasters | Year: 2012

Based on fractal theory, the features of distribution fractal, controlled fractal and influence fractal of ground fissures in the area of Hejian were studied. The fractal dimensions of relevant physical quantities, such as ground fissures, active fractures underground water, ground subsidence etc. , were calculated using the software MATLAB. It is found that the ground fissure development has self-organization property and its dimension and change reflect the complexity of the ground fissures. The plane and profile fractal features of the ground fissures reflect the non-uniformity of pregnant crack stress field of the area in plane and lengthwise directions. The formation and development of ground fissures can be viewed as an adjustment of the fracture movement, whose fractal dimension has a certain range. Ground fissures closely associated with groundwater exploitation and ground subsidence.


Zhao H.,Chang'an University | Zhao H.,Key Laboratory of Western Mineral Resources and Geological Engineering | Dang B.,Chang'an 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.


Su S.,Chang'an University | Su S.,Key Laboratory of Western Mineral Resources and Geological Engineering | He H.,Chang'an 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.


He H.,Chang'an University | He H.,Key Laboratory of Western Mineral Resources and Geological Engineering | Su S.,Chang'an 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.


He H.,Chang'an University | He H.,Key Laboratory of Western Mineral Resources and Geological Engineering | Su S.,Key Laboratory of Western Mineral Resources and Geological Engineering | Su S.,Chang'an University | And 2 more authors.
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) | Year: 2013

According to evaluation uncertainties of landslide hazard, hazard index condition of landslide geological disaster was studied. Fully considering various factors, based on information entropy and unascertained measure theory, rank-evaluating and order-arranging models of landslide hazard were established. Starting from practical geologic condition, 15 factors that influence landslide hazard were taken into account, and uncertainty measure function was obtained based on the in-situ data. The uncertainty problems in evaluation of landslide hazard were solved by qualitative analysis and quantitative analysis respectively. Information entropy theory was used to calculate the index weight of factors, credible degree recognition criteria was used to judge rank of landslide hazard, and the order of hazard was arranged. This model was employed to evaluate 17 landslides in Yingxiu-Wolong highway of S303 line. The results show that uncertainty measure method is reasonable and can provide certain reference significance for landslide hazard evaluation in the future.


Wang X.,Chang'an University | Pei X.,Chang'an University | Pei X.,Key Laboratory of Western Mineral Resources and Geological Engineering | Li R.,Chang'an University | And 9 more authors.
Geological Bulletin of China | Year: 2016

There has been long controversy over the formation age of the Xiaomiao Formation in the eastern part of East Kunlun orogenic belt due to the lack of precise age. Choosing the meta-detrital rocks of Xiaomiao Formation in Tatuo area in eastern East Kunlun orogenic belt as the study objects, the authors used LA-ICP-MS zircon U-Pb isotope geochronologic method to study the formation age of Xiaomiao Formation. The result shows that it has a wide age range (1551~2624Ma) which can be evidently divided into four groups, namely 2624~2603Ma, 2501~2290Ma, 2196~2036Ma and 1921~1551Ma, and the last group can be further divided into two subgroups of 1921~1690Ma and 1641~1551Ma. The age range 1921~1690Ma with the most intense peak value of 1783Ma represents a metamorphism and magmatism of the source region whereas the age range 2501~2290Ma represents a metamorphism of the source region. The detrital zircon also has the age range 2196~2036Ma with some detrital zircons being 2600Ma, which implies that there exists a Neoarchean basement in East Kunlun. The age range 1641~1551Ma (weighted average age equal to 1597Ma) represents the metamorphism time of Xiaomiao Formation, and the latest metamorphism age of the source region is 1690Ma, which restricts the formation age of Xiaomiao Formation, which should belong to Mesoproterozoic. The contrast of the metasedimentary zircon age range and metamorphosed basement tectonic-thermal event of the East Kunlun Mountains shows that the main sediments of Xiaomiao Formation were from Mesoproterozoic Baishahe Formation, and East Kunlun area and North China Craton have similar tectonic evolution processes from the end of Paleoproterozoic to the beginning of Mesoproterozoic, as shown by contrasting their tectonic-thermal events. © 2016, Science Press. All right reserved.


Hujun H.,Chang'an University | Hujun H.,Key Laboratory of Western Mineral Resources and Geological Engineering | Shengrui S.,Chang'an University | Ying Z.,Chang'an University | Peng L.,Chang'an 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.


He H.,Chang'an University | He H.,Key Laboratory of Western Mineral Resources and Geological Engineering | Yang X.,Chang'an University | Chao H.,Chang'an University | Zhang W.,Chang'an University
Disaster Advances | Year: 2013

Analyzing of effect on greenhouse gas such as CO2 emission to global climate and the significance carrying out research on CO2 underground storage technology system, this study used earth system science theory as a guide, studied index condition of CO2 geological storage suitability in Chinese coal-accumulating basin, fully considered the element of each respect, used analytic hierarchy process and fuzzy comprehensive evaluation, built comprehensive evaluation model of CO2 geological storage suitability in coal-accumulating basin. With Qinshui Basin as an example, the weight of each index was determined using AHP, the result was calculated using the fuzzy comprehensive evaluation, the calculation result coincided with the actual geological survey evaluation. Construction of CO 2 geological storage comprehensive evaluation model provides certain reference significance for CO2 geological storage on coal-accumulating basin.


Xu X.-C.,Chang'an University | Pei X.-Z.,Chang'an University | Pei X.-Z.,Key Laboratory of Western Mineral Resources and Geological Engineering | Liu C.-J.,Chang'an University | And 10 more authors.
Geology in China | Year: 2014

There are volcanic rocks of Caotangou Group in Yinaigou, Tianshui. The main rock types of these metamorphic volcanic rocks are metabasalt, metaandesite, metadacite and metarhyolite. These metamorphic volcanic rocks of the study area basically belong to tholeiitic basalt, whose primary magma was derived from an enriched mantle source. The metamorphic volcanic rocks of Caotangou Group are characterized by high content of LILE (Cs, Ba, Th and U) and low content of HFSE (Nb, Ta, P, Ti and Y). The tectonic environment discrimination by trace elements reveals that metamorphic volcanic rocks were formed in an island arc setting above the subduction zone. Combined with the chronological data, the authors hold that the Tianshui-Wushan oceanic basin already existed in Early Paleozoic and began subducting then, leading to the formation of Caotangou Group island arc in Yinaigou, which was similar to things of Danfeng Group in west Qinling from the viewpoints of rock assemblage, forming time and geochemical characteristics. The results obtained by the authors provide evidence for the study of Tianshui-Wushan tectonic zone which served as the west extensional part of the Shangdan paleo-suture zone in Early Paleozoic.


He H.,Chang'an University | He H.,Key Laboratory of Western Mineral Resources and Geological Engineering | Qu C.,Chang'an 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.

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