[abduhl]

This would be called a launch ramp in the industry. It is an adaptation of HDD approaches to larger diameter machines. It has been going on for decades. It is only viable where space and the final geometric constraints of the project permit. Additionally, it requires very specific geologic conditions or the construction of a structural headwall in order to avoid a sinkhole.

For example, what Boring Company is doing has already been done in the extreme limit: Herrenknecht sells a vertical shaft boring machine that is essentially a TBM turned 90 degrees. https://www.herrenknecht.com/en/products/productdetail/verti...