中国城市发展中的地质环境问题

本文在研究我国城市地质环境背景和主要地质环境问题的基础上，运用多层次动态系统方法，提出了协调城市人类工程活动和地质环境的对策。

GEO-ENVIRONMENTAL PROBLEMS OFURBANIZATION IN CHINA

Urbanization appears as a common trend in the development of various countries in the world, and particularly, the progress of urbanization is mostly prominent in the developing countries. In the last two decades the number and size of cities in China greatly expanded. The total number of cities in China increased from 213, including 11 with a population of more than one million, in 1970 to 622 at present, including 32 with a population of more than one million, presently. With the ongoing deepening of economic reforms and opening-up, urbanization will no doubt symbolize an important economic development of China in the coming century.City is a complex systerm incorporating physical environment with social environment. Large scale socio-economic activities and densely concentrated population in urban areas require the support of large scale engineering constructions, which have been becoming an iportant agent to utilize and rebuild nature' Thus, attention should be paid to environmental issues induced by engineering constructions in urbanization so as to provide the environmental conditions for urban sustainable development by coordinating engineering constitutions with the environment' The geoenvironment is one of important components of the physical environment, and macroscopically dominates the overall environment on a certain scope.The overall regionality of the physical environment in China, as a result of the interactions between the atmosphere, the hydrosphere, the biosphere and the lithosphere, is obviously governed by crustal endogenetic dynamics. The modern crustal geodynamic pattern of China continent dominates the overall terrain pattern that the terrain is steppedly distributed from the east to the west, forming three order terrain steps. The west part of the territory is the Qinghai-Tibetan plateau, while the east is marked by depressions of North China and Northeast China and formation of lowlands. Under the influence of the characteristics of terrain mentioned above, dry climatic condition was formed in the northwest part of China, whereas the southeast part is dominated by humid climate due to the intrusion of the oceanic atmospheric currents' The above terrain and climatic patterns control the overall physical environmental pattern and the distribution of natural disasters, and constitute the physical setting of urban geoenvironment.Various physical geologic and geographic settings usually are characterized by specific types of geoenvironment and combinations of environmental hazards. For instance, cities located in coastal lowland areas, such as Tianjin and Shanghai, are perplexed by land subsidence, seawater intrusion, flooding and plastic soft clay, while those in coastal hilly areas are additionally by landslide disaster. In cities situated in inland alluvial plains or inland basins, such as Xi'an and Beijing, ground crackings,surface collapse, desertification, salinization, swamping, landslide and debris flow are relatively prominent. Those cities in mountainous and hilly areas, such as Chongqin,are ghosted by slope mass movements including landslide and debris flow. In the Qinghai-Tibetan plateau, permafrost and swamping are dominant.Urban development, on one hand, depends upon the safety and stability of the geoenvironment, on the other hand, mad actively rebuild the geoenvironment. This refines that the geoenvironment of high quality. should be fully utilized in the process of urban development, and that the environment threatened by potential geohazards be effectively controlled or rationally improved. To achieve above goal, urban development and the geoenvironment should be considered as a complex dynamic system. Geoenvironmental considerations in the process of urban developmeflt, in essence, are comprehensive applications of urban geoenvironmental evaluation and prediction to urban planning. On the basis of the theoryofinteraction betweenurban construction and geoenvironment, and fully acquisition of the geoenvironmental information, modern mathematics and information science as well as sys