Abstract:The concep t of linew ise ob servat ion and po rtab le in st rum en t s are in t roduced. The in st rum en t s can be u sed in mo st geo techn ique engineering fo r f ield mon ito ring. A long a m easu ring line, m ark s and casings in sam e in terval are f ixed in stead of p robes. In th is w ay one p robe can serve m any m easu ring bo reho les and p ro jet s as w ell. Som e p robes can m easu re ax ial st rain, som e can m easu re bo th ax ial and lateral st rain o r disp lacem en t in one ho le in any direct ion s. The info rm at ion and accu racy ob tained w ill be m uch mo re and h igher than that gained by f ixed p robes based on po in tw ise ob servat ion, such as concrete st rain guage. Som e app licat ion s on f ield mon ito ring in geom echan ics are in t raduced b rief ly.