| Alluvial-proluvial fan, as a kind of typical heterogeneous aquifer, the aquifer heterogeneity building and simulation become the hot and difficult in the study of groundwater solute migration, research clearly Alluvial-proluvial fan aquifer heterogeneity distribution is the foundation and key to construct such heterogeneity texture simulation of water flow and solute migration. Taking Yunnan Dali hidden creek Alluvial-proluvial fan as the research base, by the means of research such as the hydrogeology survey and analysis of remote sensing, geophysical exploration and inversion etc. an in-depth study on distribution regularity of Alluvial-proluvial fan aquifer heterogeneity, and combined with indoor and outdoor heterogeneity parameters test, establish the Alluvial-proluvial fan aquifer heterogeneity distribution model. The use method and the result of model of Yunnan Dali hidden fairy creek Alluvial-proluvial fan aquifer heterogeneity study can provide reference for such a heterogeneous aquifer seepage simulation and solute migration, to provide guidance for the research of groundwater pollution management and remediation.Alluvial-proluvial fan development distribution range in a few tens of kilometers or even greater. Alone the ground investigation and study its evolution process is difficult, using remote sensing images from the macroscopic perspective and analysis of its space evolution has the very good effect. First setting the corresponding geophysical detection line on the sector, using the high density resistivity method detection to detect Alluvial-proluvial fan heterogeneous distribution characteristics. Through the resistivity inversion gain distribution regularity of Alluvial-proluvial fan heterogeneous aquifers, by building Alluvial-proluvial fan aquifer permeability heterogeneous distribution characteristics. United with indoor and outdoor experiments based on statistical interpolation to construct three-dimensional blunt pluvial fan aquifer heterogeneity distribution model. Through the research mainly from the following points:(1) The heterogeneity of Alluvial-proluvial fan aquifer is controlled by the hydrodynamic, sedimentary structure, terrain slope and deposition-transportation distance. Hydrodynamic conditions influence on the particle size and transportation distance, terrain slope and the transportation distance of particle deposition has a predominant function in separation and rounded, sedimentary structure is the basis of layered sedimentary heterogeneity, formation of Alluvial-proluvial fan aquifer spatial heterogeneity.(2) Resistivity inversion calculation of permeability coefficient, in a quantitative way to judge the aquifer heterogeneity. High resistivity zone permeability coefficient is relatively large; Low resistivity zone deposited particles is smaller, and the small space between particles, connectivity is poor, moisture content is relatively high, the permeability coefficient smaller.(3) By seasonal flood and perennial water permeability coefficient:in top fan surface runoff is strongly, bigger gap between particles, water transmitting ability is very strong and K value is relatively large; Fan edge hydrodynamic is weaker and into slope network flow, rivers carry sediment began to deposit, affected by the water wave force of sediment in the offshore deposits, into the weak permeable layer, K values is smaller.(4) The heterogeneity of saturation change difference is small, because of the small gap between sedimentary particles, at the same time was also filled with particles and water, sand layer is the main connecting channel in Alluvial-proluvial fan, hydraulic transmission capability is relatively weak in the upper unsaturated zone; Unsaturated zone, the permeability coefficient by the gap size and moisture content changes are positively related.(5) Vertical to the river water level elevation for groundwater saturation and the saturation line, aquifer of saturation of the K value is generally less than the K value of the saturation. Under the saturation, the permeability coefficient (K) related to the deposition of particulate matter; the upper vadose zone the permeability coefficient (K) by the top fan unsaturated layer of non-uniform distribution, become stratification more apparent in the middle fan, to the door edge is more evenly distributed. |
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