Study On The Model Of Land Subsidence In Cangzhou Area

Land subsidence is an environmental geology phenomenon. Surface elevation is reduced by nature or human activities. Land subsidence has some characteristics of lower development, long time, extensive influence, complex reason and difficult control. Now the study on the model of land subsidence emphasize particularly on relation between water and soil.Cangzhou lie on southeast of Hebei province and east of Heilonggang River in North Plain, which is the communication hub of Beijing and Tianjin to east inshore area. With the development of industry and agriculture, water need is increased drastically. The quantity of groundwater account 85 percent for total water quantity of Cangzhou. Because of exploitation of groundwater Cangzhou become the heavy disaster area on subsidence in North area. Land subsidence has bad effect on Cangzhou economic constructions and people's life. Therefore, study and control on the Cangzhou's land subsidence have a good sense on city constructions and health economy sequent developed.Model area is one of the main subsidence areas. Comparing two drills about thickness of clay in different year, analyze the influence factors of land subsidence and indicate that clay layer is the material base of land subsidence and that exploration ground water is external dynamic force to accelerate subsidence.Conceptual model of hydrological geology were created by study the condition of hydrologic geology and engineering geology. And establish the boundary conditions of the conceptual model. On the base of the conceptual models, the mathematic model of exploration groundwater land subsidence was created. Terms of source and sink on the groundwater flow model are calculated. The mathematic model is solved by Processing Modflow and Interbed-storage Package. The groundwater flow of aquifers and compaction on the clay layers are simulated exactly. Hydrogeology parameters are reasonable. By analysis the result of simulation land subsidence in Cangzhou is caused by exploration deep confined water.Based of quantity of exploration in 2005, Prediction of Cangzhou's land subsidence in 2010 is calculated by groundwater exploration land subsidence model in two conditions, which are maintenance quantity of exploration and exploration reduced every year. Water contradiction in Cangzhou can't be alleviated and land subsidence can't be controlled efficiently by reducing the quantity of exploration in short time. Therefore the work of controlling land subsidence by limitation exploration was a long-time social work. Finally, prevention and cure measures and suggestions of land subsidence such as artificial replenishment and adjusting exploitation stratum have been proposed.