Shotcrete is a placement method for concrete. It is routinely used for a wide variety of structural applications. It has been used for both initial and final linings in tunnels where it is commonly reinforced with wire mesh, fibers, or reinforcing steel. You may want to review our past Shotcrete magazine articles on tunnel shotcrete at https://shotcrete.org/archive-search/
using keywords such as “tunnel,” “underground,” and “linings.” Also, we have two position papers from our underground committee: “Spraying Shotcrete Overhead in Underground Applications,” and “Spraying Shotcrete on Synthetic Sheet Waterproofing Membranes,” that you may find informative. Also, ACI 506.5R-09, “Guide for Specifying Underground Shotcrete,” can provide insight into topics important for using and specifying underground shotcrete.