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Dang Q.,State Key Laboratory of Geo Hazard Prevention and Geo Environment Protection | Yang W.-N.,Chengdu University of Technology
Wutan Huatan Jisuan Jishu | Year: 2011

With the economic developing and city continuing to expand the scale of urban, peri-urban environment has undergone tremendous changes. One of the most outstanding performance was performance in climatic conditions from year to year changes in the city. For climate change, climate scientists have made numerous domestic and international research, this study focused on the remote sensing technology analysis the date by a way of a large area, efficiency and comprehensive analysis is using to analysis the relationship between vegetation coverage changes and Surface heat distribution. We use the TM remote sensing data of 1992 and 2006 to calculated the vegetation coverage and Surface heat distribution to reveal the relationship between vegetation coverage changes and Surface heat distribution. The results indicate that the vegetation coverage changes and Surface heat distribution show a significant negative correlation. Source


Xu T.,Dalian University | Xu T.,State Key Laboratory of Geo Hazard Prevention and Geo Environment Protection | Tang C.,Dalian University of Technology | Zhang Y.,Dalian University of Technology | Yuan L.,State Key Laboratory of Geo Hazard Prevention and Geo Environment Protection
Guti Lixue Xuebao/Acta Mechanica Solida Sinica | Year: 2011

In this paper, the 3D Parallel Realistic Failure Process Analysis(RFPA3D-parallel) is employed to investigate the bonding behavior in FRP-concrete interface based on the single shear testing results on FRP-concrete in laboratory. Numerical simulations visually reproduce the complete three-dimensional debonding process and characteristics of FRP bonded to concrete, which is a progressive process induced by meso-scopic cracks initiation and growth and macroscopic fractures form. The damage of FRP-concrete structures under external loading can be founded by monitoring the acoustic emission induced by microcracking in FRP-concrete. Based on the simulated stress evolution and deformation distribution along the length FRP sheet, the deformation and debonding failure can thus be divided into four stages, i.e., elastic, elastic-softening, elastic-softening-debonded and softening-debonded stage. The numerical approach in this study provides a useful tool for enhancing our understanding of cracking and debonding failure process and mechanism of FRP-concrete and our ability to predict mechanical performance and reliability of these FRP sheet bonded to concrete structures. Source


Xue D.,State Key Laboratory of Geo Hazard Prevention and Geo Environment Protection | Xue D.,Chengdu University of Technology | He Z.,State Key Laboratory of Geo Hazard Prevention and Geo Environment Protection | He Z.,Chengdu University of Technology | And 2 more authors.
Energy Education Science and Technology Part A: Energy Science and Research | Year: 2012

In this article, Qingchuan and Pingwu County geohazard-prone areas in Sichuan Province is taken as the study prototype, combination of background characteristics and geohazard present situation, through systematic analysis of the evaluation index system, integrated use of RS and GIS technology to study multi-scale risk assessment of geohazard. Base on the study of geohazard distribution law of Pingwu and Qingchuan two counties, rapid risk assessment is conducted; example for typical geohazard - Donghekou landslide and Wenjiaba landslide, a small scale risk assessment is taken on. The results of this evaluation will avoid blind mitigation investment and provide a reference for the quick response. © Sila Science. All rights reserved. Source


Yuan L.,Dalian University | Xu T.,Dalian University | Xu T.,State Key Laboratory of Geo Hazard Prevention and Geo Environment Protection | Xu Q.,State Key Laboratory of Geo Hazard Prevention and Geo Environment Protection
Applied Mechanics and Materials | Year: 2011

Spallation of concrete under dynamic loading has been the hot issue of concern about civil engineering structures and protective engineering. In the present paper, the principle of propagation of stress wave and the induced spallation process along a one-dimensional bar and the RFPA-Dynamics code which considers the heterogeneity of the concrete materials are briefly introduced. In order to numerically investigate the effect of mesh size of numerical model on the computational results, the failure process of concrete with three mesh sizes under dynamic loads was numerically simulated using RFPA-Dynamics code. Numerical simulations show that the failure patterns of concrete with different mesh sizes under dynamic stress waves are different. It is found that for the numerical models with the same mechanical parameters, the smaller mesh size of the numerical model is, the longer propagation of stress wave delay, the smaller the compressive stress is, thus the greater the tensile stress is, and the number of cracks is increasing, in general, rupture is more serious. The accuracy of mesh is little to improve when the number of the grid increases to a certain value. © (2011) Trans Tech Publications. Source


Xu T.,State Key Laboratory of Geo Hazard Prevention and Geo Environment Protection | Zhao J.,Ecole Polytechnique Federale de Lausanne | Zhao G.F.,Ecole Polytechnique Federale de Lausanne | Yuan L.,Dalian University | Liu P.,Dalian University
Rock Stress and Earthquakes - Proceedings of the 5th International Symposium on In-Situ Rock Stress | Year: 2010

Wave propagation process and shallow spallation of rock slope under the dynamic loads is numerically simulated to investigate the applied incident compressive stress wave on the fracturing process and failure induced in the rock mass. Heterogeneity of the rock materials is taking into account and the RFPAdynamics is firstly briefly described. Then, the propagation of compressive stress wave along a one-dimensional rock bar is performed to validate the effectiveness of the RFPA-dynamics code. Furthermore, the shallow spallation of rock slope under the dynamic loads is carried out. Numerical simulations capture the whole process of the propagation of incident compressive stress waves in the rockmass and the reflection of stress wave upon rock slope surface and the shallow spallation of rock slope induced by the reflected tensile stress wave, which is obviously different from the failure pattern of rock slope under static loads, where a circular slip failure surface normally formed in the rockmass. The approach suggested in this paper also can be used generally for estimating dynamic load influ-ences on the development of stress and displacement fields around rock slopes. © 2010 Taylor & Francis Group, London. Source

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