Relying　solely　on　soil　properties　may　not　fully　ensure　the　performance　of　capillary　barrier　covers　at　limiting　landfill　gas　(LFG)　emissions.　This　study　proposed　to　install　passive　gas　collection　pipes　in　the　coarse-grained　soil　layers　of　capillary　barrier　covers　to　enhance　their　performance　at　limiting　LFG　emissions.　First,　the　LFG　generation　rate　of　municipal　solid　waste　and　its　influencing　factors　were　analyzed　based　on　empirical　formulas.　This　information　provided　necessary　bottom　boundary　conditions　for　the　analyses　of　LFG　transport　through　capillary　barrier　covers　with　passive　gas　collection　pipes　(CBCPPs).　Then,　numerical　simulations　were　conducted　to　investigate　the　LFG　transport　properties　through　CBCPPs　and　reveal　relevant　influencing　factors.　Finally,　practical　suggestions　were　proposed　to　optimize　the　design　of　CBCPPs.　The　results　indicated　that　the　maximum　whole-site　LFG　generation　rate　occurred　at　the　end　of　landfilling　operation.　The　gas　collection　efficiency　(E)　of　CBCPPs　was　mainly　controlled　by　the　ratio　of　the　intrinsic　permeability　between　the　coarse-　and　fine-grained　soil　(K2/K1)　and　the　laying　spacing　between　gas　collection　pipes　(D).　E　increased　as　K2/K1　increased　but　decreased　as　D　increased.　An　empirical　expression　for　estimating　E　based　on　K2/K1　and　D　was　proposed.　In　practice,　CBCPPs　were　supposed　to　be　constructed　once　the　landfilling　operation　finished.　It　is　best　to　select　the　fine-　and　coarse-grained　soils　with　K2/K1　exceeding　10,000　to　construct　CBCPPs.　©　2024　Elsevier　B.V.