The paper introduces the craft procedure and operation points of the topdown construction method in construction of air-raid shelters under urban roads, points out according treatment methods for some special parts, and proves by the practice that the topdown construction can be adopted in the underground air-raid projects to ensure the stability and safety of buildings in two sides and provides better reference for similar projects.%介绍了盖挖逆作法在城市地下人防工程应用中的工艺流程及操作要点，并对特殊部位提出了有针对性的处理方法，实践证明在地下人防工程采用盖挖逆作法施工，保证了两侧建筑物的稳定和安全，对今后同类工程具有很好的借鉴作用。
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