If your diameter is less than 250 mm it could be either micropile or helical pile and vice versa. If duration is small and diameter is less than 250m, it is a micropile. A liner of comprehensive depth upto hard rock / strata is necessary. M.S. or HDP pipe liners https://kung-fu47147.ttblogs.com/10053192/difference-between-micropile-and-other-piles-can-be-fun-for-anyone