I was just thinking, how did an army hold ground once they took it, did they dig in another front line trench or just put some troops on it. And when a front line is broken through, did the retreating troops have to dig out a whole new trench?
Sorry if this is a dumb question, I was just really confused when reading about the spring offensive.
It's not just one trench facing one trench; it can be quite a bit more complicated. From the FAQ, this thread has the best answers on the practicalities of trench fighting, with u/ElusiveBiscuit and u/NMW providing their input. The second link in u/ElusiveBiscuit's answer has since died, but the bird's eye view picture is also on Wikipedia; that should help you visualise just how complex and expansive the trenches on the Western Front looked like.
