A METHOD FOR INVESTIGATING AN ANCHORED ROD-LIKE BODY HAVING AN ACCESSIBLE END, AND APPARATUS FOR CARRYING OUT THE METHOD.

摘要

Method and apparatus study of a rod-shaped body (1, 61) which is anchored in a surrounding material (62) and accessible through one end (16) to determine the state of the anchor body and length. Transient elastic oscillations are produced of the accessible side of the body. The oscillation consists of a wave of flexure which causes deformation of the body variant relative to the amplitude and the phase on the body section. The flexure wave propagates in the longitudinal direction of the body and is partially reflected by the discontinuities of the body and / or anchoring. Transient elastic oscillations comprising the flexure waves reflected at these discontinuities and returning to the accessible end of the body are received and detected. The position and magnitude and / or type of at least some discontinuities are estimated with the aid of the time position and amplitude of the wave reflected flexure. Discontinuities of interest are the beginning and end of the anchor, the end of the body and possible cracks or fractures in the body and / or its anchorage. The method and apparatus are primarily for the study of in situ anchors (bolts) in the rock which are embedded in concrete, although the method and apparatus can be used to study at least partially with other body-shaped rod.