Land Subsidence Analysis And Numerical Simulation Of Dongguang

Due to the uncontrolled exploitation of groundwater and the infinite growth of industrial and agricultural pumping wells in the North China Plain,the deep confined water continued to over-exploit in the long-term,and the groundwater level continued to decrease,triggering a series of secondary disasters such as land subsidence.Dongguang County is the most typical area.In order to meet the requirements of comprehensive national governance,it is the current priority to analyze the land subsidence in the area and simulate the change of groundwater flow in the area.Through the analysis of layerwise mark monitoring data,it is concluded that the deep aquifer in the study area has a large contribution rate to the land subsidence in the region,and the sedimentation rate is greatly affected by the season and is obviously related to the groundwater level.For different types of soils,high pressure consolidation test data were used to analyze the compressibility and resilience under different pressure conditions.It was found that the burial depth and the particle size matching soil compressive and rebound resilience have an important impact.Therefore,the ground subsidence of the study area is analyzed from three aspects: soil depth,particle gradation and groundwater level.Using the overconsolidation ratio data to analyze the state change of the soil after water release,it is found that the greater the depth,the greater the effective stress caused by the release of water from the soil,the faster the effective stress growth rate,and when the aquifer is completely drained,most soils will be converted to under-consolidated state.By analyzing various indicators measured by geotechnical tests,the relationship between physical and mechanical indicators and depth is obtained,and the linear relationship between physical and mechanical indicators is obtained by correlation analysis.The regression equation is used to obtain the regression equation between the compressibility index and each physical and mechanical index,and the equation is simplified by using the linear relationship of each index obtained before.The gradation analysis of the soil in the study area was carried out to obtain the gradation characteristics of different types of soil.The sedimentary law of the study area and the particle size characteristics of the aquifer were obtained by referring to other drilling data in the Dongguang area.Combined with the international soil classification method,the particle gradation curve partitions of different types of soil in the study area were summarized.GMS was used to simulate the groundwater flow in the Dongguang area.After a series of parameter setting and parameter adjustment,the groundwater flow model suitable for the Dongguang area was obtained,and the model was used to predict the future groundwater level change trend in the Dongguang area.According to the actual situation of national overexploitation treatment,the groundwater level after limited mining was simulated.This study can provide ideas for over-extraction control and water level recovery in the study area,guidance for future control of land subsidence and reference for further accurate model simulation.