Study On Decreasing Water Level Of Confined Water In Soft Soil Two-layer Deep Excavation Through Interior Model Experiment

Unique hydrogeology feature of soft soil two-layer structure in Wuhan city determines particularity of decreasing confined water in deep excavation. Combining achievements in past scientific research, this thesis summarizes some problems in the process of decreasing water ,the problems contains: important parameters such as percolation coefficient, interfering radius etc; designers get parameters from their experience and make their choice of limited prospecting materials too simply, because of the limits, designer can't make quantitative analysis on groundwater; differences on breakwater effect of setting water-tight screen is still existed, although research evolvement in this field is done; they can't grasp the hydrogeology parameters accurately in that it influences rightness of designing in deep excavation water-decreasing.The thesis makes model experiment on imminent problems existed in deep excavation water-decreasing project, the concrete contents is as follows:(1) Soft soil two-layer structure stratum is simulated, deep excavation water-decreasing model test is carried on and the law of water motion is observed depending on precise instruments.(2) In order to validate the rightness of the parameters, hydrogeology parameters is measured, such as discharge, percolation coefficient and hydraulic pressure using the precise instruments and existing formula and arithmetic.(3) Water-tight screen model experiment is done and based on it, its actual effect is surveyed.(4) Water flow model experiment is made and hydraulic pressure variation is observed, "the detainment and displacement "of semipervious aquifers in the process of decreasing water is also studied.(5) Based on VB program, the experiment data is handled dynamically and test curves is drew.