The　failure　mode　of　the　soil　behind　the　rigid　support　structure　of　excavations　parallel　to　tunneling　was　simulated　using　the　adaptive　finite-element　limit　analysis　method.　This　study　showed　the　effects　of　tunnel　diameter,　tunnel　construction　clear　spacing,　excavation　insertion　ratio,　and　soil　strength　on　the　failure　mode　of　the　soil.　Based　on　the　simulated　results　obtained　from　finite-element　software,　a　stress　field　was　constructed　for　the　portion　above　the　horizontal　plane　at　the　bottom　of　the　excavation　support　structure.　Three　types　of　boundary　value　problems　were　solved　based　on　different　regional　divisions.　Eventually,　the　stress　state　at　any　point　within　the　plastic　zone　was　calculated,　providing　the　active　earth　pressure　on　the　support　structure　adjacent　to　the　tunnel　during　its　construction.　A　comparison　between　the　stress　characteristic　method　calculation　results　and　the　finite-element　simulation　results　showed　consistency,　confirming　the　efficiency　and　accuracy　of　the　stress　characteristic　method　in　calculating　the　earth　pressure　on　the　support　structure　of　excavations　parallel　to　tunneling.