There　are　a　large　number　of　structural　planes　distributed　in　the　surrounding　rock　of　a　tunnel,　and　this　is　one　of　the　key　factors　causing　a　tunnel＇s　instability.　Due　to　different　geological　and　historical　conditions,　the　distribution　characteristics　and　the　occurrence　of　structural　planes　in　the　rock　mass　also　have　significant　differences.　In　engineering,　it　is　common　to　encounter　structural　planes　that　cut　across　the　tunnel　section　and　have　a　significant　impact　on　the　stability.　The　occurrence　of　structural　planes　is　a　key　factor　controlling　the　mechanical　behavior　of　the　surrounding　rock.　Based　on　this,　laboratory　uniaxial　compression　tests　were　carried　out　by　constructing　a　small　tunnel　physical　model　with　single　structural　planes　of　different　inclination　angles.　A　related　numerical　simulation　analysis　was　also　carried　out.　This　research　indicates　that:　(1)　Under　the　influence　of　a　single　structural　plane,　the　dip　direction　with　30　degrees-60　degrees　is　the　most　dangerous　situation,　and　when　the　dip　angle　of　the　structural　plane　is　between　38　and　88　degrees,　it　will　slip　along　the　structural　plane.　(2)　According　to　the　mechanical　mechanism,　there　are　three　types　of　cracks:　tensile　cracks,　shear　cracks,　and　tensile　shear　cracks.　According　to　the　deformation　characteristics,　there　are　four　types:　tension,　friction,　bending,　and　shear.　(3)　There　is　a　certain　correlation　between　the　strength　of　a　single　discontinuity　rock　mass　and　that　of　a　multi-jointed　rock　mass.　When　the　dip　angle　of　the　joints＇　combination　is　45　degrees+60　degrees,　the　rock　mass　is　in　its　weakest　state.