Abstract: By analysising the hydrogeology and engineering geology conditions of Tangshan coastal area, a new understanding of formation mechanism of land subsidence in Tangshan coastal area was proposed.Firstly, the mathematical model for development tendency of groundwater funnel is established, by which the model is identified.Then the conception of storage co-efficient is introduced to establish the varying tendency model of groundwater level, in combination with the buried depth of water in groundwater funnel.Finally, combining with the annual land subsidence rate and the mathematical model for buried depth of groundwater, a calculation model for land subsidence in Tangshan coastal area is built, and the calculating result conforms to the real land subsidence and deformation.

Key words: Land subsidence, Environmental and geological hazard, Scientific computing, Tangshan coastal area