A　test　platform　of　the　earth　pressure　balance　shield　is　designed　and　manufactured.　Taking　a　field　project　as　the　background,　the　test　model　with　single　cobble　strata　and　two　existing　tunnels　is　planned,　and　the　test　of　shield　under-crossing　the　existing　tunnels　in　the　cobble　strata　is　conducted.　The　surface　settlement,　the　normal　earth　pressure　acting　on　the　existing　tunnel,　and　the　circumferential　strain　of　the　existing　tunnels　are　measured.　During　the　shield　advancing　process,　two　collapse　pits　are　caused　on　the　ground　surface　directly　above　the　right　side　walls　of　the　horseshoe　tunnel　and　rectangular　tunnel,　respectively.　Based　on　the　measured　surface　settlements　and　the　earth　pressure　on　the　existing　tunnels,　collapse　mechanism　of　the　cobble　soil　around　the　existing　tunnel　is　revealed.　Meanwhile,　deformation　feature　of　the　existing　horseshoe　and　the　rectangular　tunnels　is　obtained　according　to　the　measured　circumferential　strain.