砾石含量对崩积体基质及优先流入渗的影响与微观机制OA

To explore the influences of gravel content on the matrix and preferential flow infiltration in colluvial deposits and its microscopic mechanisms in Benggang,this study prepared five soil-rock mixtures with gravel mass content of 30%,40%,50%,60%,and 70%.CT scan and surface ring infiltration method were adopted to study the pore conditions and infiltration characteristics of colluvial deposits.The results showed that the presence of gravel reduced the number and roundness of pores,while increasing the total pore area,average pore diameter,and connectivity(P<0.05).With the increase in gravel content,all parameters of total infiltration,matrix infiltration,and preferential flow infiltration(initial infiltration rate,turning infiltration rate,steady infiltration rate,and average infiltration rate)showed an overall increasing trend.For colluvial deposits with gravel content of 30%and 40%,matrix infiltration dominated only in the initial stage,while for those with gravel content of 60%and 70%,preferential infiltration dominated in all stages,and the contribution rate of preferential infiltration to total infiltration reached 79%.All infiltration parameters showed positive correlations with pore ratio,average pore diameter,connectivity,and effective pore specific surface area(P<0.05).Among them,pore connectivity had the most prominent impacts on both matrix infiltration and preferential flow infiltration.In conclusion,gravel content mainly promotes matrix and preferential flow infiltration in colluvial deposits by enhancing pore connectivity,thereby affecting total infiltration.