|
Guanghua Cheng, China Geological Survey (China)
Gangyi Zhai, China Geological Survey (China)
Yuxun Zhuang, China Geological Survey (China)
Xiangmin Cai, Beijing Institute of Geological Survey and Research (China)
|
|
Since 2003, China Geological Survey has been conducting pilot projects of urban geological survey in six cities: Beijing, Shanghai, Hangzhou, Tianjin, Nanjing and Guangzhou. Field work has been completed and we are now in the process of synthesis and evaluation. (1) The main features of the urban geological survey in China include: (a) funding by both the central and local governments; (b) collaboration among local geological survey organizations and with other research institutions and universities; (c) systematically collecting all previous data and building a database of original data; (d) using a multidisciplinary approach (including geology, hydrogeology, geo-engineering, environment and mineral deposits) from project planning and implementation to project synthesis and evaluation; and (e) presenting survey results in a series of maps that can be visualized in 3D and that are friendly to users in geology, urban planning, engineering design and construction, as well as to government decision makers and managers. (2) The main tasks of the urban geological survey include: (a) survey of 3D geology and feasibility study of development of underground space; (b) survey and sustainability assessment of geological resources; (c) survey and risk assessment of geological hazards; (d) geochemical survey and environmental assessment of soil and surface water; and (e) database development and management of information that can be visualized in 3D. (3) Remote sensing is used to survey urban development and evolution, change in water body and land, change in erosion or deposition along river and lake shorelines, and evolution of urban landforms. Drilling is used to investigate 3D geology. Geophysical methods are used to connect geological contacts between drill holes, define bedrock surface, locate active faults, survey geological hazards (such as karst), and survey ground water. Geochemical methods are used to survey and assess the quality of the current geological environment. Modern information technology (e.g., 3D modelling and visualization, spatial database and computer networks) is used to develop platforms for management, application and service of urban geological information that have the all-in-one capacity for data entry, database management and visualization and analysis of 3D geospatial data. (4) Through the pilot projects, a dynamic database of urban geology has been developed and 3D geological structure of unconsolidated (Quaternary) sediments of the cities has been elucidated. Some preliminary results have been used in urban planning, site selection and construction, and their social-economic value is promptly realized. In addition, a technical standard and a set of techniques and methods for urban geological survey have been developed. The public geological work by the central government has also guided and given an impetus to public geological work by local governments.
|
