A preferential flow model considering the dynamic changes of desiccation cracks
To address the problem of quantitative evaluation of the preferential flow model under the desiccation cracks,based on the double pore domain infiltration theory,this paper proposes a new preferential flow model considering the dynamic changes of desiccation cracks with the combination of Green-Ampt infiltration model.In the proposed model,the cracked soil is separated into matrix domains besides the cracks(L-matrix domain),under the cracks(B-matrix domain)and crack domain.Then,the effects of rainfall intensity,initial crack area ratio,and crack depth on the water ponding time,infiltration amount and depth of preferential flow are simulated and discussed.The results show that infiltration amount of preferential flow produced by desiccation cracks occupies 73.4％to 91.4％of the total precipitation.Its ultimate infiltration depth during rainfall is 3.1 to 7.2 times deeper than the crack depth.With the increase of rainfall intensity,the water ponding time of matrix domain decreases and the infiltration depth of preferential flow increases.During rainfall,the decreased crack area ratio leads to the decrease of infiltration amount of preferential flow.Moreover,it is found that with the increase of initial crack area ratio,the infiltration amount of the L-matrix domain decreases and the preferential flow infiltration increases,whereas its infiltration depth decreases.The increased crack depth mainly delays the water ponding time of the crack domain and increase the infiltration depth of preferential flow.In conclusion,the simulated results are consistent with the practical infiltration process within the desiccation cracks,and it also avoids errors and inconvenience caused by the defining hydraulic property of cracks.
desiccation crackspreferential flowdouble pore domain modelGreen-Ampt infiltration model
万方数据
维普
