In　a　traditional　tunnel　waterproof　and　drainage　system　(WDS),　the　waterproof　board　is　easily　damaged　because　of　improper　construction　control,　resulting　in　groundwater　entering　the　gap　between　the　waterproof　board　and　the　second　lining.　Groundwater　seeps　out　along　weak　links,　such　as　cracks　and　construction　joints,　in　the　lining,　because　there　is　no　drainage　channel　between　the　waterproof　board　and　the　second　lining,　and　causes　water　leakage　problems　in　the　tunnel.　It　is　difficult　to　treat　the　water　leakage　damage　in　the　traditional　tunnel　WDS,　and　the　maintenance　cost　is　high.　To　address　the　shortcomings　of　the　traditional　WDS,　a　composite　WDS　with　an　additional　drainage　board　between　the　tunnel　waterproof　board　and　the　second　lining　is　proposed.　It　has　the　advantages　of　adjustability,　antiblocking　capability,　and　ease　of　maintenance.　To　verify　the　effectiveness　of　the　system,　tests　were　carried　out　on　the　drainage　capacity　and　anti-blocking　capacity　of　three　geotechnical　drainage　materials　(capillary　drainage　board,　convex　shell　drainage　board,　and　geotextile)　adopted　in　the　composite　WDS.　The　tests　were　conducted　under　different　water　and　support　pressures　using　a　self-developed　test　device.　In　addition,　the　application　of　different　geotechnical　drainage　materials　in　the　composite　tunnel　WDS　was　verified　on-site　at　a　tunnel　project　under　construction.　The　main　results　are　as　follows.　For　the　same　value　of　drainage　water　pressure,　the　drainage　capacity　of　the　three　drainage　materials　is　a　decreasing　function　of　the　support　pressure.　The　geotextile　has　the　largest　drop　in　the　drainage　capacity,　followed　by　the　capillary　drainage　board;　the　convex　shell　drainage　board　has　the　smallest　drop.　For　the　same　values　of　drainage　water　and　support　pressures,　the　drainage　capacity　of　the　geotextile　decreases　significantly　after　muddy　water　drainage　tests　are　performed　20　times,　and　the　drainage　capacities　of　the　capillary　drainage　board　and　convex　shell　drainage　board　decrease　slightly.　Moreover,　the　drainage　of　the　convex　drainage　board　is　mixed　with　sand,　whereas　the　drainage　of　the　capillary　drainage　board　is　clean　water,　indicating　that　the　capillary　drainage　board　is　better　at　resisting　blockage.　The　field　test　data　of　the　composite　WDS　show　that　the　additional　drainage　board　between　the　waterproof　board　and　the　second　lining　has　good　drainage　and　pressure　relief　capabilities,　and　can　effectively　reduce　the　water　pressure　behind　the　lining.　The　development　of　composite　WDS　can　provide　a　reference　for　the　design　of　tunnel　WDS　and　the　treatment　of　water　leakage.　©　2021,　Editorial　Department　of　China　Journal　of　Highway　and　Transport.　All　right　reserved.