Which of the following is not a type of shoring?

Shoring refers to the process of supporting a structure or excavation to prevent collapse. Each of the types of shoring mentioned, except for blast shields, serves to provide this structural support.

Screw jacks are a type of adjustable support often employed in construction to provide temporary stability. Hydraulic shores utilize hydraulic systems to exert pressure for stabilizing structures or excavations, making these a critical element in managing unstable earth and ensuring worker safety. Lag beams, typically made from wood, are utilized to brace and support walls or other structures during excavation or construction processes.

Blast shields, on the other hand, are designed to protect individuals and structures from the effects of explosive blasts. They serve a very specific purpose related to safety during demolition or military operations and do not function as shoring. Therefore, this distinction highlights that blast shields do not fit within the defined categories of shoring.