Securely held extensometer for detection of positional changes in e.g. rock

摘要

The extensometer has one or more anchor portions (1), each of which has at least one axial section (5) with a much reduced (i.e. at least 1 cm reduced) dia. for securing a strong hold in the material. The extensometer pref. has two or more spaced anchor portions (1) with a common sensor tube (4), etc., the space between the anchor portions, having the same cross-section as the anchor portions, being filled with an elastically flexible filler, pref. polyethylene bodies with closed pores.