Time filter

Source Type

Zhai Y.,Beijing Normal University | Guo Y.,Beijing Normal University | Zhou J.,Beijing Institute of Geological Engineering | Guo N.,Beijing Normal University | And 2 more authors.
Hydrological Processes | Year: 2014

Rapid population growth and increased economic activity impose an urgent challenge on the sustainability of water resources in Beijing. Understanding the spatial and temporal variability of precipitation is of the upmost importance in order to sustain the region's water resources. Two time series, one long term (1724-2010) from a single meteorological station and a shorter time series (1980-2010) from 20 different meteorological stations within the Beijing area, were analysed using Linear Regression, Moving Average, Mann-Kendall, Rescaled Range and Spatial Interpolation methods. Results from both the long- and short-term meteorological data show a mean annual precipitation rate of 600mm and 540mm respectively. Annual precipitation rates have decreased during the 21st century by an estimated 100mm or 16% in comparison to the 1990s. The 1980-2010 data show an increase in precipitation during the early 1990s followed by a sharp decrease during the subsequent years. The change of annual precipitation with time is more random and diverse in comparison to space. The main local impact factors (terrain, urbanization and elevation) and how they work on the local precipitation especially the spatial diversity are identified qualitatively. Generally speaking, (1) the annual precipitation of the plain area is more than that of the mountainous area (terrain effect), (2) the annual precipitation of the urban area in the plain area is obviously more than that of the surrounding suburb area (urbanization effect) and (3) the annual precipitation of the lower location is approximately more than that of the higher location (elevation effect). © 2013 John Wiley & Sons, Ltd. Source

Chen Q.,Tsinghua University | Chen Q.,Beijing Institute of Geological Engineering | Li Z.,Tsinghua University | Zhang Z.,Tsinghua University
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2010

Due to blasting and other disturbances during the process of excavation of underground caverns, loosening zone around the caverns can be found, and it would become larger with time at high geostress. Several loosening zone models and its simulation method proposed are introduced by other scholars. Based on the models, a new model is proposed that is related to frequency and displacement, which can be used to large and complex underground caverns. Due to different forms and distribution loosing zones around the underground caverns, its application to displacement back analysis for Jinping I hydropower underground caverns is introduced. Therefore, it should consider loosening zone in back analysis, and the proposed loosening model is suitable for underground engineering. Source

Li Y.,Beijing Institute of Geological Engineering | Zhao C.,University of Science and Technology of China | Chao Y.,China University of Geosciences
2011 2nd International Conference on Mechanic Automation and Control Engineering, MACE 2011 - Proceedings | Year: 2011

The writers designed the drawings management system which based on ObjectARX.Net technology, and on using PDM management process analyzed users' needs of enterprise drawing management. The designed system contained drawings database, server and client programs. And for different clients it realized functions like, design drawings, review, storage, release, query, browsing. © 2011 IEEE. Source

Zhai Y.,Beijing Normal University | Zhai Y.,Engineering Research Center for Groundwater Pollution Control and Remediation | Wang J.,Beijing Normal University | Wang J.,Engineering Research Center for Groundwater Pollution Control and Remediation | And 5 more authors.
Journal of Radioanalytical and Nuclear Chemistry | Year: 2013

The Yongding River Alluvial Fan is a northwestern part of the North China Plain, at which Beijing is located. Since 1950 and especially 1970, excessive groundwater exploitation has resulted in a significant drop of groundwater table, and it's believed that groundwater will be intensively used continuously in the future. It's essential to reveal the renewability and the evolution of the groundwater for reasonable management, which was achieved based on the analyses of the major ions and environmental tracers in groundwater. According to the dating results of 3H, CFCs, and 14C, the age of the shallow and deep groundwater was from <5 to 60 a and from <4,000 to >12,000 a, respectively. The recharge rate determined by the groundwater age generally had a decreasing trend from the NW (0.40-1.44 m/a) to the SE (0.07-0.48 m/a). Na and HCO3 accumulated from the NW to the SE and the latter was the dominant anion. Chemical modification occurred progressively along the flow paths. The water type of the shallow and deep groundwater changed from Ca-Mg-HCO3 to Na-HCO3 and from Ca-Mg-HCO3 to Ca-Na-Mg-HCO3 and Na-Ca-Mg-HCO3 from the NW to the SE, respectively. The shallow groundwater was vulnerable and susceptible to contamination scattered throughout the region, which would probably further extend to the deep groundwater because of the vertical groundwater flow especially through the preferential pathways due to their increasing hydraulic connections. © 2013 Akadémiai Kiadó, Budapest, Hungary. Source

Liu Y.,Beijing Institute of Hydrogeology and Engineering Geology | Liu J.,Taiyuan University of Technology | Li S.,Beijing Institute of Geological Engineering | Dong P.,Beijing Institute of Hydrogeology and Engineering Geology | Sun Y.,Beijing Institute of Hydrogeology and Engineering Geology
Advanced Engineering and Technology II - Proceedings of the 2nd Annual Congress on Advanced Engineering and Technology, CAET 2015 | Year: 2015

The numerical simulation of groundwater was a necessary tool for the groundwater movement research and water resources evaluation. Through three-dimensional numerical simulation modeling of groundwater flow and the solute transport modeling in the upper of Chaobai river alluvial fan in Beijing, this research predict and evaluate that the construction of recycled water plant will bring about direct effect and indirect harm to groundwater environment Taking COD as the main pollution index, the model predicted that the concentration of pollutant COD in groundwater is far less than drinking water standards, after recycled water plant used for 30 years later. Therefore, the use of recycled water basically has no impact on the surrounding groundwater environment. © 2015 Taylor & Francis Group, London. Source

Discover hidden collaborations