Temporary lagging of shotcrete must meet some standard as it is the shoring holding back the earth. If reinforcing is used in the design of the temporary shoring it must be fully encapsulated to provide the design strength of the lagging as specified in the design. A temporary structure may have a low safety factor but the strength of the rebar and shotcrete must meet the design specifications. Many times it is more important to do good shotcrete for the temporary shoring just because it has a lower factor of safety and therefore less allowance for poor construction practices.