The　high　water　content　of　the　surrounding　rock　in　loess　tunnels　will　lead　to　the　deterioration　of　rock　strength,　causing　deformation　and　damage　to　the　initial　support　structure　and　thereby　affecting　safety　during　construction　and　operation.　This　article　first　analyzes　the　strength　characteristics　of　loess　under　different　water　contents　through　indoor　physical　and　mechanical　tests.　Secondly,　based　on　numerical　simulation　results,　the　ecological　environment,　and　design　requirements,　the　water　content　threshold　is　determined.　Finally,　a　reinforcement　scheme　combining　surface　precipitation　measures　and　curtain　grouting　measures　is　proposed,　and　the　reinforcement　effect　is　analyzed　based　on　on-site　monitoring　data.　The　results　show　that　as　the　water　content　of　loess　increases,　the　cohesion,　internal　friction　angle,　and　elastic　modulus　of　the　surrounding　rock　all　decrease,　leading　to　an　increase　in　the　sensitivity　of　the　surrounding　rock　to　excavation　disturbances　and　a　deterioration　in　strength.　During　the　construction　process,　it　shows　an　increase　in　the　vault　settlement　and　sidewalls＇　convergence.　During　the　process　of　increasing　the　distance　between　the　monitoring　section　and　the　palm　face,　the　settlement　and　convergence　of　the　tunnel　show　a　rapid　growth　stage,　slow　growth　stage,　and　stable　stage.　The　water　content　threshold　is　determined　to　be　22%.　The　reinforcement　scheme　of　combining　surface　precipitation　measures　with　curtain　grouting　measures　not　only　meets　the　requirements　of　the　ecological　environment　but　also　makes　the　settlement　and　convergence　values　lower　than　the　yellow　warning　deformation　values　required　by　the　design.