Andy Dingley writes:

Usually with studs rather than bolts. You glue the stud in place,
leave it to set and then bolt up later. Rock climbers have
"interesting" opinions on the virtues of these.

Cavers too.

Lots of testing has been done on "eco anchors"

http://cncc.org.uk/tg_placement.html
http://cncc.org.uk/tg_test_1.html
....
http://cncc.org.uk/tg_test_4.html

and several more pages on the same site.

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