Anchors 3. The behaviour of grouped inclined anchors in sand : 11F, 3R. GROUND ENGNG. V6, N6, 1973, P34–41

Abstract

Research into the bahaviour of groups of inclined ground anchors is described. Results of laboratory tests are presented and discussed. The effect of anchor spacing and inclination was investigated in a test rig in which metal discs simulating the underreams were embedded. These were connected by a steel tendon to an instrumental linkage and a motor driven pull-out head. The instrumented linkage containing strain gauges and transducers was connected to a 20 channel bridge and digital voltmeter which produced direct punching of results on tape as the pull-out progressed. The article gives results in graphical form of many tests on groups of three and five anchors covering a range of inclinations and spacings. Differences were found in the loads taken by the 'leading' and 'trailing' anchors which were always compared with the performance of a single control anchor. Using stereo-photogrammetric techniques to record movements within the leighton buzzard sand in which the anchors were embedded, a picture of the 'pressure bulb' around the anchor group was obtained. The change in shape of this bulb with changes in other variables is discussed.