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1. (WO1979000929) A METHOD FOR INVESTINGATING AN ANCHORED ROD-LIKE BODY HAVING AN ACCESSIBLE END,AND APPARATUS FOR CARRYING OUT THE METHOD
Latest bibliographic data on file with the International Bureau

Pub. No.: WO/1979/000929 International Application No.: PCT/SE1979/000092
Publication Date: 15.11.1979 International Filing Date: 12.04.1979
IPC:
B06B 1/06 (2006.01) ,E21D 21/02 (2006.01) ,G01V 1/00 (2006.01)
B PERFORMING OPERATIONS; TRANSPORTING
06
GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
B
GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
1
Processes or apparatus for generating mechanical vibrations of infrasonic, sonic or ultrasonic frequency
02
making use of electrical energy
06
operating with piezo-electric effect or with electrostriction
E FIXED CONSTRUCTIONS
21
EARTH OR ROCK DRILLING; MINING
D
SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
21
Anchoring-bolts for roof, floor, or shaft-lining protection
02
having means for indicating tension
G PHYSICS
01
MEASURING; TESTING
V
GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
1
Seismology; Seismic or acoustic prospecting or detecting
Applicants:
Inventors:
Priority Data:
780416113.04.1978SE
Title (EN) A METHOD FOR INVESTINGATING AN ANCHORED ROD-LIKE BODY HAVING AN ACCESSIBLE END,AND APPARATUS FOR CARRYING OUT THE METHOD
(FR) METHODE D'ETUDE D'UN CORPS EN FORME DE TIGE ANCRE AYANT UNE EXTREMITE ACCESSIBLE, ET APPAREIL D'APPLICATION DE LA METHODE
Abstract:
(EN) A method and apparatus for investigating a rod-like body (1, 61) which is anchored in a surrounding material (62) and which has an accessible end (16), for determining the state of the anchorage of the body and its length. Transient elastic oscillations are excitated in the accessible end of the body. The oscillations comprise a flexural wave causing a deformation of the body varying with respect to amplitude and phase over the cross-section of the body. The flexural wave propagates in the longitudinal direction of the body and is partially reflected at discontinuities of the body and/or the anchorage. Transient elastic oscillations comprising flexural waves reflected at such 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 of the discontinuities are estimated with the aid of time-position and amplitude of the reflected flexural waves. Discontinuities of interest are the beginning and end of anchorage, the end of the body and possible cracks or fractures in the body and/or its anchorage. The method and the apparatus are primarily intended for in-situ investigation of concrete-bond (63) rock anchors (bolts), although the method and apparatus can be used for at least partially investigating other anchored rod-like bodies.
(FR) Methode et appareil d'etude d'un corps en forme de tige (1, 61) qui est ancre dans un materiau environnant (62) et accessible par une extremite (16), pour determiner l'etat d'ancrage du corps et sa longueur. Des oscillations elastiques transitoires sont produites du cote accessible du corps. Les oscillations consistent en une onde de flexure qui provoque une deformation du corps variant par rapport a l'amplitude et la phase sur la section du corps. L'onde de flexure se propage dans le sens longitudinal du corps et est partiellement reflechie par les discontinuites du corps et/ou l'ancrage. Les oscillations elastiques transitoires comprenant les ondes de flexure reflechies a ces discontinuites et retournant a l'extremite accessible du corps sont recues et detectees. La position et la grandeur et/ou le type d'au moins quelques discontinuites sont estimees a l'aide de la position-temps et l'amplitude des ondes de flexure reflechies. Des discontinuites presentant un interet sont le debut et la fin de l'ancrage, l'extremite du corps et les fissures ou cassures possibles dans le corps et/ou son ancrage. La methode et l'appareil sont avant tout destines a l'etude in situ d'ancres (boulons) dans la roche qui sont noyees dans du beton, bien que la methode et l'appareil puissent etre utilises pour etudier au moins partiellement d'autres corps en forme de tige.
Designated States:
Publication Language: English (EN)
Filing Language: English (EN)