I would think poor ground strength makes cut-and-cover even more attractive relative to the alternative (drilling). For tunnels drilled under streets, the stre

I would think poor ground strength makes cut-and-cover even more attractive relative to the alternative (drilling). For tunnels drilled under streets, the street is supported by rock/soil. For cut-and-cover, the street is supported by concrete and steel. Maybe you're thinking that it's just impossible to have shallow tunnels at all with the type of soil? I don't think that's how things work, but I'd love to hear from an expert.