THE STUDY OF PRELIMINARY DIVISION OF LAND SUBSIDENCE UNITS

Regional land subsidence induced by groundwater overdraft has became a global problem. The land subsidence is relatively development in our country especially, North China plain, Fen-Wei Basin and Yangtze River delta. Subsidence preventive was a significant challenge in urban geological. This paper aims to put forward the conception of land subsidence unit based on ideas of systematic land subsidence preventive. It considers that structure, lithology, groundwater system and aquifer structure are based to divide land subsidence units. Three mainly factors are confirmed by analysis main geological conditions and formation mechanism of land subsidence, include division of groundwater system, aquifer system and thickness of compressible layers. The division principle of land subsidence units was proposed mainly based on the three factors. Using Beijing plain as a target area, the twenty units of land subsidence are divided based on spatial analysis platform of GIS.The units of land subsidence are concordant with the status of land subsidence, and generally characteristic of land subsidence are reflected in some extent, which are based on compare and analysis the relationship between subsidence units and subsidence areas. It is proposed that land subsidence units could be applied for investigation, monitoring, study and preventive of land subsidence, then thoroughly develops the study of control mode of subsidence division. It can make more reasonable, accurate and systematic for prevention and control of land subsidence in the future.