More and more governments and other project owners come up with very creative delivery ways. Intended to minimize the risks for the project owners, such news ways often create additional risks for the contractors. Those new alternative delivery methods are design-build, CMGC, Progressive DB, CMAR, or public-private partnership (P3) etc.

Although such new delivery methods are not limited to tunneling and applies to larger scope of infrastructure, tunnels and other underground projects are generally riskier than the most of the other forms of  infrastructure projects.

Such as the design-build method, which requires a contractor put a figure for the construction of a tunnel whose design is not finalized, if started at all.

This is the new game and as se have seen in UK recently (Stonehenge Tunnels - UK contractors shun the tender but overseas JVs submit bids for the £1.25bn project), contractors are not happy with it. But there are always other contractors who will participate in such tenders, therefore it is "adapt and survive" rather than "my way and die".

To  mitigate the risks for such projects, risk management comes up ever more important area to work on.

This article by Nasri Munfah, P.E., Director of Tunnel and Underground Engineering for AECOM, published in Tunnel Business Magazine 'explains the ways to fairly allocate geotechnical risk mitigation across project teams'

https://tunnelingonline.com/controlling-tunneling-project-risk-implemented-by-alternative-delivery/