An　emerging　construction　method　using　a　concrete　box　can　effectively　reduce　the　risks　such　as　face　collapse　and　extrusion　at　the　launch　stage　of　shield　or　tunnel　boring　machine　(TBM)　tunnelling.　It　occupies　a　small　construction　plant　and　can　be　applied　to　complex　urban　environments,　especially　in　mountainous　cities.　However,　the　failure　mechanisms　of　the　tunnel　face　at　the　launch　stage　of　the　novel　method　are　still　not　properly　understood.　Based　on　the　upper-bound　theorem　of　the　limit　analysis　(LA),　two　multi-block　failure　models　are　proposed　in　this　work　for　tunnelling　launch　in　semi-infinite　body　and　in　areas　with　slope　overburden.　The　limit　equilibrium　(LE)　method　is　used　to　obtain　the　vertical　earth　pressure　of　upper　finite　soil　mass　considering　the　soil　arching　effect.　The　comparisons　of　the　support　pressure,　failure　zone　and　dip　angle　of　the　slip　surface　obtained　from　the　proposed　models　with　the　results　of　numerical　simulations　and　previous　studies　indicate　that　the　proposed　approach　provides　realistic　and　satisfactory　predictions.　The　effects　of　soil　cohesion,　internal　friction　angle,　slope　dip　angle,　reduction　coefficient　and　the　ratio　of　tunnel　diameter　to　overburden　width　are　further　assessed.　The　proposed　models　were　applied　to　two　practical　engineering　cases　to　determine　reinforcement　measures　using　grouting　and　pipe-roof　methods　required　during　the　tunnelling　launch,　and　were　demonstrated　to　be　able　to　provide　useful　guidance　for　the　practical　operations.　©　2023　Elsevier　Ltd