Study On Groundwater Pollution Prediction Of A Site Under The Condition Of Seismic Mutagenesis

With the development of society,construction land with relatively simple geological conditions is gradually saturated.In order to explore the evaluation method of groundwater environmental pollution in construction sites under complex conditions,it is necessary to conduct targeted assessments of sudden pollution events that may occur in complex sites.Planning and disaster prevention and mitigation provide theoretical support.This paper selects the earthquake among the causes of sudden pollution as the research object,based on previous research conclusions on the direction of the permeability change of the aquifer after being disturbed by the earthquake,and the change range of the permeability of the porous and fractured aquifer after the earthquake.Explore the possible environmental impact of earthquakes on groundwater environmental pollution sites,and provide reference for groundwater environmental assessment in earthquake-prone areas.In this paper,taking the groundwater environmental impact assessment of a waste landfill in Yunnan as an example,the hydrogeological conditions of the site were investigated in an area of 13.36 km2,the geological and hydrogeological conditions of the site were analyzed,and the necessary hydrogeological parameters were obtained through field tests.Combined with the actual working conditions of the landfill site,the research area is rationally generalized,and the groundwater flow and solute transport model is established by using Visual MODFLOW.Comparative simulation of non-traditional situations.Taking the maximum working cycle of the facility as the simulation time boundary,it can be seen from the simulation results that under the condition that the groundwater quality of the site is well monitored and the leakage source is checked and repaired in time,when the pollutant concentration reaches the peak value after the earthquake,the pollution halo range and There is little difference in similar leakage scenarios without earthquakes.The impact of earthquakes on groundwater pollution is mainly manifested in the change of pollutant concentration and the long-term migration range of pollutants.In the slow seepage scenario without earthquakes,the peak concentration of the pollution halo center is 6.18% to 6.2% of the pollution source concentration,and this value will change to 6.25% to 7% after the earthquake,with an increase of 0.8‰ to 8.2‰.In terms of the natural attenuation of pollution halos,the impact of the earthquake is particularly obvious.In the case of acute leakage after the earthquake,the excess range of residual pollutants can reach 177.76% of that in the case of slow leakage.There is still a small amount of excess residue.As far as the research site is concerned,the natural attenuation of COD,ammonia nitrogen,BOD,fluoride,and lead should be the focus of attention in the harmless work after closure.The research shows that although the change of aquifer permeability under the influence of the earthquake is recoverable,but because there is a certain correlation between the earthquake and the seepage,when the effects of the two are superimposed,the concentration of the groundwater environmental pollution does increase and increase.For the abnormal change of the duration growth,the continuation of the earthquake on the site pollution should be considered when assessing and predicting the risk of groundwater environmental pollution in high-earthquake-risk areas.