With　the　rapid　development　of　metro　construction,　the　calculation　of　loosening　earth　pressure　acting　on　tunnels　has　become　a　research　hotspot　in　the　field　of　tunnel　engineering.　Accurate　prediction　of　the　loosening　zone　around　tunnels　is　crucial　for　determining　the　loosening　earth　pressure.　To　simplify　and　precisely　estimate　the　extent　of　the　loosening　zone　around　tunnels,　its　boundaries　were　first　postulate　as　two　inclined　straight　lines.　Then,　a　formula　for　the　sliding　angle　was　derived　considering　tunnel　size,　buried　depth　of　the　tunnel,　and　other　conditions　based　on　the　Mohr-Coulomb　failure　criterion,　and　thus　the　loosening　zone　of　strata　around　the　tunnel　could　be　determined.　Finally,　the　lateral　pressure　coefficient　on　the　sliding　surface　and　the　formula　for　calculating　the　loosening　earth　pressure　above　tunnel　were　deduced　by　integrating　the　theory　of　principal　stress　axis　rotation　in　the　loosening　zone　soil　mass　with　the　assumption　of　an　inclined　sliding　surface.　The　study　shows　that　the　sliding　angle　increases　with　the　increase　of　the　internal　friction　angle　of　soil,　and　initially　decreases　with　the　increase　in　tunnel　burial　depth　ratio,　subsequently　stabilizing.　When　the　trajectory　line　of　the　major　principal　stress　is　assumed　to　be　circular,　the　calculation　is　more　straightforward　and　conducive　to　wider　application.　The　results　obtained　from　the　analytic　solution　presented　in　this　paper　align　well　with　the　actual　test　results,　indicating　its　applicability　for　the　calculation　of　loosening　earth　pressure　above　the　shield　tunnel　in　sandy　strata.　©　2024　Chinese　Academy　of　Railway　Sciences.　All　rights　reserved.