Importance of joint parameters on deformations observed in dynamically loaded models of large excavations

This paper describes the results of physical scale modeling of tunnels in joint systems using 20,000 discrete blocks of weak brittle material. Conclusions are drawn on how to treat joint strength and stiffness in modeling. The paper is divided into two parts; first, the deformation and instability observed in dynamically loaded physical joint models are summarized, and the effect of joint parameters mentioned; and secondly, recent work on joint strength and stiffness scale effects is summarized. Suggestions are made for modifying and improving some of the joint parameters used in numerical JOINT SLIP and CAVS Tensile Failure models