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Fan X.,Southwest University of Science and Technology | Zhang Y.,Southwest University of Science and Technology | Yang J.,Sichuan Institute of Geological Engineering Investigation
Journal of Natural Disasters | Year: 2012

Wenchuan earthquake is the most serious natural disaster in China in the recent years. The earthquake induced a large number of landslides which brought about serious casualty and property loss. Based on the investigation and surveying of seismic landslides in Beichuan, Sichuan Province, the characteristics and influence factors of landslide development were studied. The purpose of this study is to provide a valuable theoretical basis for the reduction and prevention of the seismic landslide disaster. In this paper, the advantageous gradient extensions and the most favorable gradients of seismic landslides were studied. The results show that, the area-frequency distribution of the seismic landslides follows logarithmic distribution, which differs from the rainfall landslide which follows power distribution. The angle between the fault rupture direction and the landslide direction controls the distribution of frequency, gradient and area of the seismic landslides. When the landslide direction agrees with fault rupture direction, the proportion of landslide frequency and area are larger and the average gradient is smaller because of throwing out action under earthquake. When landslide direction is opposite to the fault rupture direction and the same with the fault incline direction, the proportion of landslide frequency and area are smaller and the average gradient is larger due to collision and crash in the earthquake. Source

Liu D.-L.,Chengdu University of Information Technology | Zhou Z.-Y.,China University of Petroleum - Beijing | Wu Q.,Sichuan Institute of Geological Engineering Investigation | Tang D.,Chengdu University of Information Technology
Petroleum Science | Year: 2016

Symbols are considered as the language of a map; hence, accurate understanding of the meaning of symbols is crucial when obtaining geographical information from a map: the symbolisation of spatial data is of key importance in cartography. A geographical information system (GIS) provides a convenient mapping platform and powerful functions for spatial data symbolisation, while the presence of various mapping standards impedes the understanding of maps and sharing of map information. On the other hand, the available GIS platforms find it difficult to deal with automatic conversion between maps and different mapping standards. To resolve this problem, an approach for symbol recognition and automatic conversion is proposed, and a conversion system based on the approach and the ArcGIS Engine platform is developed to realise automatic conversion between maps produced based on different mapping standards. To test these conversion effects of the proposed system, the petroleum sector is chosen as the research field and the mutual conversion of a map in practical work among the three mapping standards (i.e. the Chinese Petroleum, Shell and USGS standards) governing this field is taken as a case study. The results show that the conversion system has a high conversion accuracy and strong applicability. © 2015, The Author(s). Source

Huang C.,University of Maryland University College | Huang C.,Sichuan Institute of Geological Engineering Investigation | Rokita S.E.,University of Maryland University College | Rokita S.E.,Johns Hopkins University
Frontiers of Chemical Science and Engineering | Year: 2015

Biological application of conjugates derived from oligonucleotides and quinone methides have previously been limited by the slow exchange of their covalent self-adducts and subsequent alkylation of target nucleic acids. To enhance the rates of these processes, a new quinone methide precursor with an electron donating substituent has been prepared. Additionally, this substituent has been placed para to the nascent exo-methylene group of the quinone methide for maximum effect. A conjugate made from this precursor and a 5'-aminohexyloligonucleotide accelerates formation of its reversible self-adduct and alkylation of its complementary DNA as predicted from prior model studies.[Figure not available: see fulltext.] © 2015 Higher Education Press and Springer-Verlag Berlin Heidelberg Source

Zhou X.-Y.,Sichuan Institute of Geological Engineering Investigation | Deng A.-F.,Chongqing University
Yantu Lixue/Rock and Soil Mechanics | Year: 2010

Analyzing three dimension is the developmental trend of numerical manifold method. Three-dimensional manifold element with hexahedral finite element covers is constructed by cover displacement function of numerical manifold method, strain matrix, stiffness matrix and equilibrium equations are derived. Simultaneity, linear elastic model is mostly adopted on numerical manifold method for problem analysising persently, but nonlinear model is researched very little, calculating formulations of numerical manifold method for nonlinear analysis based on the characters of numerical manifold method and constitutive models of rock and soil mass is presented. The elastic modulus of E-μ model and K-G model is altered to describe the nonlinear relationship by midpoint incremental method; in fact subsection linear ralationship is substituted for nonlinear ralationship. Finally, an example of foundation settlement calculation is given; the calculation result shows the validity of nonlinear analysis of three-dimensional numerical manifold method for rock and soil mass. Source

Zhang S.,Chengdu University of Technology | Zhang S.,Hong Kong University of Science and Technology | Xu Q.,Chengdu University of Technology | Hu Z.,Sichuan Institute of Geological Engineering Investigation
Engineering Geology | Year: 2016

Red mudstone landslides are widespread in southwest of China. The development and distribution of deep-seated landsides with slow inclination are closely related to the special soft rock properties of the red mudstone layers. Most previous studies focused on the failure mechanisms of rain-induced shallow landslides. Studies on deep-seated landslides in red layer zones are still limited. In order to ascertain the basic failure mechanisms of red layer landslides with a gentle inclination, a fatal landslide named as Shibangou landslide, which occurred in Sichuan, China, was investigated. This paper aims to (1) conduct laboratory tests on the reduction in shear strength of a red layer to identify the water-rock coupling effect; (2) investigate variations in the microscopic structure of the soft rock found within a red layer after rainfall infiltration; (3) discuss the failure mechanisms of red layer landslides with slow inclination. Results from shear test of mudstone from the Shibangou landslide revealed that there is a tendency that behavior of soft rock can be transferred to soil in different days of immersion. The delineation threshold of shear strength of the red layer is determined as 6 days of immersion. Microstructures of clay minerals become loose and porous due to the contacts between the particles transferred from the face-edges, face-face associations into edge-edge, and face-edge associations. Therefore, the intramolecular and cemented expansions of illite are the basic mechanisms which lead to structural damage, structural decay, and strength attenuation of soft rock in red layer under the condition of rainwater infiltration. © 2016 Elsevier B.V. All rights reserved. Source

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