As　the　main　material　composition　of　many　large　landslides　in　China　and　other　countries,　the　soil-rock　mixtures　(SRMs)　have　attracted　many　researchers　to　investigate　their　mechanical　and　hydraulic　characteristics　in　the　past　several　decades.　Although　in-door　and　in-situ　tests　still　play　the　dominant　role　in　obtaining　the　material　parameters　of　SRMs,　numerical　methods　are　seen　as　a　better　choice　regarding　economy　and　practicality.　As　a　competitive　numerical　method,　the　numerical　manifold　method　(NMM),　which　can　solve　continuous　and　discontinuous　problems　in　a　unified　framework,　is　used　in　the　present　work　to　investigate　the　hydraulic　characters　of　SRMs.　Before　investigating　the　hydraulic　characters　of　SRMs　with　NMM,　the　aggregate　structural　model　and　discretized　model　of　SRMs　should　be　built.　To　effectively　build　the　aggregate　structure　model　of　SRMs　with　high　rock　content,　a　simplified　random　sequential　addition　method,　which　is　based　on　E(A,　B)　concept　and　background　mesh,　is　firstly　developed.　Then,　the　recently　proposed　parallel　preprocessing　strategy　of　NMM　is　used　to　generate　the　discretized　model　of　SRMs.　Finally,　an　illustrative　example　regarding　the　determination　of　effective　permeability　coefficient　of　SRMs　is　solved　with　3DNMM.　The　proposed　numerical　model　in　investigating　SRMs　deserves　further　investigation.　©　2023　Elsevier　Ltd