A Modified Calculation Model For Groundwater Glowing To Horizontal Seepage Wells And Its Application

In recent years, the horizontal seepage well with its high yield, low consumption, good management, the relatively low water-supply cost and others advantages was recognized and widely used in arid and semi-arid areas in the Northern Shaanxi. The corresponding calculation model also got certain development. However, however, limitations of this existing model are discovered including:the model has a great number of nodes; when there are two or more horizontal seepage wells working together, there will be too many nodes to calculate effectively; the model cannot depict the irregular distribution of radiating bores accurately and so on. These disadvantages limit the application of the model. So, the study of the modified calculation model is very significant.This thesis relies on both China National Natural Science Foundation Study on the calculation model and physical modeling of horizontal seepage well groundwater-collecting structure working mechanism and Study on the calculation model and physical modeling of non-casting-well groundwater-collecting structure working mechanism and Shaanxi Geological Exploration Foundation Groundwater exploration near the Yellow year in the Energy and Chemical Base in the Northern Shaanxi. Based on the theory of coupled seepagepipe flow model put forwarded by Chenchongxi, the aquifer is conceptualized as a single water-bearing media and the well pipe system is conceptualized as a discrete conduit network which consists of pipes and nodes. Using the exchange flow rate between the aquifer and the well pipe as the couple key, the discrete well pipe and the finite-difference grid are coupled and the modified calculation model is set up. The model has the following advantages:(1) There are fewer nodes. Using the equivalent hydraulic conductivity as the couple key in existing model, we need subdivide the grid to depict the complicated structure of horizontal seepage wells, so there are a great number of nodes. In this thesis, the well pipe is separated. Using the exchange flow rate between the aquifer and the well pipe as the couple key, the number of the nodes reduced greatly.(2) When the horizontal seepage well is applied in the water-supplying field, there always are two or more horizontal seepage wells works together. There will be too many nodes to calculate the reasonable yield. The modified calculation model has fewer nodes, so we can calculate the effectively.(3) The character of radiating bores can be depicted accurately. When calculating the exchange flow between pipe and aquifer, the permeability of the screen or wall material of radiating bores is considered and irregular distribution of the radiating bores is well conceptualized.Based on analyzing geological and hydrogeological conditions of study area systematically, the reasonable groundwater yield was calculated by the modified model at various exploitation schemes. The results show that the way using five horizontal seepage wells (one with 5 chambers) is the most suitable way to exploit groundwater according with actual situation in the study area. Groundwater exploration has the sufficient supplies amount of resources to guarantee through argumentation and it's feasible from economic and technological perspectives. The results of this research can be used to guide and reference to calculation of reasonable yield of the horizontal seepage wells and the construction work later.