Research On The Influence Of Karst Pipeline Shape On Seepage Law

Our country has a wide range of karst area,widely distributed in the southwest,north China,southern Tibet,social and economic development in karst area is inevitable to karst pipeline related projects.Darcy law is only applicable to the Reynolds number is less than 10 porous medium,and hard to used in karst conduit flow calculation,and the United States geological survey's latest Modflow-CFP method still exists some shortcomings,in order to further improve the karst conduit flow velocity formula of accuracy,for the formation of karst pipeline,the flow of the pipeline flow,the quantitative calculation of the friction is particularly important.This article explores the shortcomings of the Modflow-CFP method:1.The CFP method will almost into a round,large difference with real situation,and through the relevant data collection and field investigation,karst fissure development in the development of karst pipeline can be lava have great relationship,and along the fissure oval.According to karst pipe position,it can be divided into confined karst conduit(primary stage in karst pipeline development),diving karst pipe(the ultimate stage in karst pipeline development).According to the different karst pipeline,the flow formula of the two types of karst pipes is derived.2.The pipe cross section is established mathematical model of two-dimensional fractal geometry,fractal dimension and scale coefficient is analyzed,the sampling length relation for rough surface,using fractal dimension inversion karst pipe cross section,calculation of pipe wall roughness and fractal dimension quantitative relationship,at this stage can be obtained in the laboratory using scanning tunneling microscopy(STM)cross section features forward quantitative calculation of fractal dimension and karst pipe roughness coefficient,reduced because of the improper selective coefficient of friction caused by the error.3.The main problems existing in the quantitative study friction is hard to quantify physical model,the physical model experiment of pipeline by using 3 d printers,to a certain degree of surface features will be quantified,the results show that the use of 3 d printer making model,physics experiment validation has certain feasibility.