Parameter design of yielding layers for squeezing tunnels

摘要: Abstract Tunneling in a soft rock mass under high situ stress often results squeezing deformation. Supports that use yielding layers are suggested to address the deformation of tunnels. However, feasible design methods for layer have not been proposed, especially determination P s and thickness d . In this study, laboratory test is conducted verify effect support. The show pressure secondary lining reduced with installation layer. comparisons between uniaxial tests confined unconfined conditions showed whole stress–strain curve can be obtained by its compression tests. divided into three stages: elastic stage, stage failure stage. Compared other lining, polyurethane (PU) density (70–100) more suitable as it has capacity adjustable stress. A method PU considering key parameters tunnel determined.