Experimental Study And Numerical Simulation Of Seepage From A Seasonal River

Daguhe River is one of the main source of water and an important sources of industrial and agricultural in Qingdao. The floods of Daguhe River usually occurred from July to August, which lasted for 3 to 5 day.The seepage of riverway to groundwater directly impacts the flux of floods and the supply of groundwater. Take a test to the seepage from Daguhe River can provide scientific basis to build a system of flow(particularly peak flow) and groundwater seepage, as well as offer a reference to other research of scheduling season river.In this study, we carried out the meteorology, hydrology, geology and other aspects of the investigation along the Daguhe River. Take both experimental study and numerical simulation to explore the rule and effect of seepage in different riverway. We made Shangshai dam and Yifengdian dam as objects, mensurated the unsaturated characteristics of samples; simulated the unsaturated infiltration with laboratory studies and field studies; established the numerical model under different conditions of vadose zone to validate the results of the laboratory tests; analyzed the characteristic and rule in unsaturated infiltration with the software VS2DT. As a result of these studies, we obtained some new understanding and conclusions as follows:(1) We selected the Shangshai dam and Yifengdian dam as studying objects,tested the curves of soil water characteristic and hydraulic conductivities of the samples, fitted the parameters and taked analyses by Van Genuchten model.(2) We studied the saturated-unsaturated infiltration and changes of flux with time under the fixed head, through the soil column and trough in the laboratory studies, discussed the rule of moisture transfer. Through the data's collation and comparison,we know that the moisture infiltrations not only had sameness but also had their own characteristics, which were related with the way of infiltration, the river rock, the moisture content of vadose zone, the time of infiltration.The vertical flux of coarse sand were 0.003ml/(s*cm2) and 0.002ml/(s*cm2) when the intial moisture contain was 0.44% and 9.30%,and the vertical flux of fine sand were 0.002ml/(s*cm2) and 0.0018ml/(s*cm2) when the intial moisture contain was 2.50% and 9.65%. The side flux of coarse sand were 0.002ml/(s*cm2),0.0011ml/(s*cm2) and 0.0008 ml/(s*cm2), when the intial moisture contain was 2.60%,7.35% and 13.98%,and the side flux of fine sand were 0.0026ml/(s*cm2),0.002ml/(s*cm2) and 0.0016ml/(s*cm2) when the intial moisture contain was 3.20%,7.61% and 16.20%.(3) Through field studies,we determined the change of flux of seepage. According to the laboratory test results.We tested that the steady flux of Yujiaxiaoli was 0.028ml/(s*cm2), the flux of Wangbi was 0.010ml/(s*cm2) and the flux of Nashaliang was 0.023ml/(s*cm2).(4) By using the parameters, upper and lower boundary conditions, and initial conditions, which were determined by studies, we used the software VS2DT to establish a vadose zone numerical model to simulate the moisture infiltrations, got the validation that the parameters could be used to calculate the unsaturated Seepage from the Daguhe River.(5) We used the software VS2DT to take the vadose zone moisture infiltrations theoretical model in a preliminary applied research. We established a generalized model and analyzed the effects of intial moisture contain and the hand to the vertical and flux.