The Study On Precipitation Experiment And Numerical Simulation Of The Loess Strate

This paper, based on the pit development theory of water conservancy projects, analyzes and summarizes the applicable conditions for different precipitation ways,features of pits, main factors affecting the quality of pit precipitation project as well as the basic theory and equation concerning ground water and groundwater flow. Through the major research of comprehensive precipitation experiment of the open channel linking the southern bank of the first stage Yellow River Crossing Project in the middle section of South-North water diversion project, the single well precipitation test and the productive multi-well test have been carried out and the related data has been calculated and analyzed. During the phase two of the multi-well experiment, processing mudflow was employed to establish a numerical model of precipitation. Through the calculation of water level drawdown and the fitting analysis of the actual data, this paper test and verifies the rationality of selected parameters. The main reseach contents are as follows.(1) This paper summarizes pit precipitation methods and theories, probes into themechanism and applicable scope of pit precipitation for water conservancy project and puts forward the methods of lowering groundwater level under different conditions in loess zone.(2)single well precipitation test was carried out in accordance with the hydrogeologicalcharacteristics of the experimental zone; then relevant parameters wre calculate from the data obtained from the test so that a preliminary precipitation scheme was proposed in this paper.(3) The integrated precipitation scheme was determined afer analyzing the results ofproductive multi-well test. Through the comparison between the numerical model of precipitation established by Processing Modflow and the actual data, the error was very slight,which suggest that the selected model boundary is appropriateand can meet the precision requirements in engineering design.(4) By combining the engineering practice of integrated precipitation test and applyingthe above-mentioned theories and methods, the precipitation design and construction in loess ares have been summarized and its rationality and effectiveness analyzed.