Combining the field monitoring results of a deep-buried tunnel in Chongqing,the dynamic characteristics of the surrounding rock system under high in situ stress wasanalyzed by phase space reconstruction, calculating c...Combining the field monitoring results of a deep-buried tunnel in Chongqing,the dynamic characteristics of the surrounding rock system under high in situ stress wasanalyzed by phase space reconstruction, calculating correlation dimension, Kolmogoroventropy and largest Lyapunov exponents.Both the Kolmogorov entropy and largestLyapunov exponents show that the surrounding rock system is a chaotic one.Based onthis, a local model was applied to predict surrounding rock displacement, and a nonlineardynamic model was derived to forecast the interaction of the surrounding rock and supportstructure.The local method was found to have an extremely small total error.Also, thenonlinear dynamic model forecasting curves agree with the monitoring ones very well.It isproved that the nonlinear dynamic characteristic study is very important in analyzing rockstability and predicting the evolution of rock systems.展开更多
Deterioration of city air quality is the serious problem in the process of rapid urbanization and economic development in China. Taking 74 cities that have implemented the new Ambient Air Quality Standards （GB3095- 2...Deterioration of city air quality is the serious problem in the process of rapid urbanization and economic development in China. Taking 74 cities that have implemented the new Ambient Air Quality Standards （GB3095- 2012） since 2013 as examples, using statistical and ArcGIS spatial analysis method, the multi-scale temporal and spatial variations characteristics and the impact of social and economic factors on urban air quality variations, are analyzed in this paper. The main research conclusions are as follows：（1） Air quality in Chinese cities shows very significant seasonal variations, with higher air quality in summer and autumn, and lower air quality in spring and winter; （2） Seen from a daily pollution perspective, air pollution is very serious and will tend to be more serious in the future; （3） Seen from an hourly variation perspective, urban air quality is time coupled with social production and urban living; （4） The overall spatial pattern of urban air quality is high in the east and north and low in the west and south, but with an obvious trend towards regional integration. （5） Cities in different regions have different factors that cause air quality variations. In general, urbanization level and energy consumption per GDP are the common factors.展开更多
基金Supported by the New Century Excellent Talent Foundation from MOE of China(NCET-09-0844)the National Natural Science Foundation of China(50804060,50621403)
文摘Combining the field monitoring results of a deep-buried tunnel in Chongqing,the dynamic characteristics of the surrounding rock system under high in situ stress wasanalyzed by phase space reconstruction, calculating correlation dimension, Kolmogoroventropy and largest Lyapunov exponents.Both the Kolmogorov entropy and largestLyapunov exponents show that the surrounding rock system is a chaotic one.Based onthis, a local model was applied to predict surrounding rock displacement, and a nonlineardynamic model was derived to forecast the interaction of the surrounding rock and supportstructure.The local method was found to have an extremely small total error.Also, thenonlinear dynamic model forecasting curves agree with the monitoring ones very well.It isproved that the nonlinear dynamic characteristic study is very important in analyzing rockstability and predicting the evolution of rock systems.
基金National Natural Sciences Foundation of China(A Study on the resource-environment base for the Modern Man-Land Relationship in China,No.8122015)
文摘Deterioration of city air quality is the serious problem in the process of rapid urbanization and economic development in China. Taking 74 cities that have implemented the new Ambient Air Quality Standards （GB3095- 2012） since 2013 as examples, using statistical and ArcGIS spatial analysis method, the multi-scale temporal and spatial variations characteristics and the impact of social and economic factors on urban air quality variations, are analyzed in this paper. The main research conclusions are as follows：（1） Air quality in Chinese cities shows very significant seasonal variations, with higher air quality in summer and autumn, and lower air quality in spring and winter; （2） Seen from a daily pollution perspective, air pollution is very serious and will tend to be more serious in the future; （3） Seen from an hourly variation perspective, urban air quality is time coupled with social production and urban living; （4） The overall spatial pattern of urban air quality is high in the east and north and low in the west and south, but with an obvious trend towards regional integration. （5） Cities in different regions have different factors that cause air quality variations. In general, urbanization level and energy consumption per GDP are the common factors.
