| The frequent occurrence of landslide on vegetated slops,causes incalculable loss of people'life and property,which Attracted extensive attention of scholars,but most remain in the qualitative research,Quantitative research is imminent.With the increase of landslide events,soil water infiltration and preferential flow play an important role in the process of landslide breeding.Macropore is the main path of preferential flow,and there are many kinds of macropores.At home and abroad,there have been many studies on the phenomenon of the traditional macropore flow(the root canal,the wormhole channel and the dry shrinkage crack),and it has been recognized as the positive role in the process of rainfall infiltration.However,the study of single pore is not enough,especially root-soil interstice,a new type macropore,we need a more comprehensive analysis.Based on CT scanning data,Volview software was used to reconstruct soil 3D map and root distribution map to understand the distribution of root system in soil;using Navier-Stokes equation to calculate the physical concept model of the soil-root interstice,the velocity distribution in the transverse gap is analyzed,meanwhile,combine with C language and the lattice boltzmann method,the flow velocity nephogram is analyzed,and the seepage field of the transverse root-soil gap in the rainfall infiltration process is comprehensively analyzed.Binarization processing method of CT scanning data,CT test sections need,using lattice Boltzmann method,and combined with the Matlab program,read through a series of CT slices before treatment,process changes velocity nephogram and velocity,vertical seepage field of mesoscopic simulation.By using the above methods,the influence of the root-soil interstice on the rainfall infiltration process is analyzed deeply,and the conclusions are as follows:(1)CT scanning technology combined with Volview software,can be a good way to restore the root distribution in the soil of the real situation,and applied to the analysis of soil seepage,it can lay the foundation for the diversion of root-soil interstice.The CT values of each substance were classified by the method of point selection,isolation and synthesis,and finally the CT value of the gravel was between 1500 and 3071.The CT value of the root system was between(-1200)and(-800),and the CT value of the weathered crust was between 800 and 1200;(2)The flow velocity distribution of the lateral root-soil interstice is that,the velocity of the center line is the maximum velocity,is also 1.5 times that of the average velocity,while to both sides of the wall velocity is zero.The velocity distribution of vertical root-soil interstice is that,with the increase of depth,the flow velocity decreases gradually,which is mainly dependent on some well-connected interstices channels;(3)Flow velocity of numerical simulation in lateral root-soil interstice is that,the maximum velocity offset from the centerline position toward the lower end;(4)Vertical velocity distribution of root-soil interstice under different vegetation is that,the average flow rate,maximum flow rate increased with the increase of depth,flow rate increase and decrease with depth of soil layers,woody vegetation communities were greater than the flow velocity,herbaceous vegetation communities,two vegetation communities in the soil root gap diversion contribution rate increases with depth,the proportion of local wood layer are larger than the herb the range of values,respectively 40.91-93.33%,15.00-50.00%?... |
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