Flexible　immersion　joints　are　one　of　the　most　important　components　in　immersed　tunnels,　and　their　compression　performance　determines　the　water-proofing　capability　and　structural　safety　of　the　joints.　However,　current　research　on　the　compression　behavior　of　immersion　joints　is　relatively　insufficient,　and　more　experiments　are　needed　on　the　related　parameter　to　support　its　real-life　application.　Taking　an　immersed　tunnel　in　the　Hong　Kong-Zhuhai-Macau　link　as　a　case　study,　the　models　of　the　tunnel　element　and　immersion　joint　with　a　geometric　scale　ratio　of　1/10　were　designed,　followed　by　a　large-scale　experiment　as　well　as　the　testing　of　the　mechanical　properties　of　the　rubber.　The　axial　force-compression　behaviors　of　the　immersion　joints　were　studied　by　applying　an　axial　force　to　the　joint,　and　the　structural　and　material　test　results　were　compared.　The　results　show　the　non-linear　behavior　of　the　immersion　joint.　The　compression　performance　of　the　joint　is　affected　by　the　compression　property　of　the　GINA　rubber.　The　results　of　the　structural　tests　are　generally　2-3　mm　lower　than　those　of　the　mechanical　property　tests,　the　relative　difference　being　21%.　In　order　to　verify　the　experimental　results,　both　two-dimensional　and　three-dimensional　rubber　numerical　models　were　established.　A　comparison　of　the　experimental　and　numerical　results　was　undertaken　to　analyze　the　effects　of　friction　force　between　the　element　and　ground　support,　length,　shape,　and　transversal　restraint　of　the　rubber　and　quantify　them　in　detail.　The　results　indicate　that　the　effects　of　friction　force,　length,　and　transversal　restraint　of　the　rubber　are　relatively　small　and　can　be　ignored.　However,　the　longitudinal　dimension　exerts　a　significant　influence,　resulting　in　a　maximum　difference　of　8.8%.　Finally,　a　simplified　mechanical　model　was　proposed　to　simulate　the　compression　behaviors　of　the　immersion　joints　in　accordance　with　the　test　results.　The　results　show　that　it　can　also　be　applied　to　axial　mechanical　analyses　of　other　flexible　joints.　©　2019,　Editorial　Department　of　China　Journal　of　Highway　and　Transport.　All　right　reserved.