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Modelling of compaction ground anchors.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Modelling of compaction ground anchors./
Author:	Egan, Derek.
Description:	1 online resource (340 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 80-01, Section: C.
Contained By:	Dissertations Abstracts International80-01C.
Subject:	Civil engineering. -
Online resource:	click for full text (PQDT)
ISBN:	9780438138728

Modelling of compaction ground anchors.
Egan, Derek.

Modelling of compaction ground anchors. - 1 online resource (340 pages)

Source: Dissertations Abstracts International, Volume: 80-01, Section: C.

Thesis (Ph.D.)--The University of Manchester (United Kingdom), 1997.

Includes bibliographical references

Pressure grouting of compaction anchors deployed in granular soils is a widely used construction technique. The grout bulb, which forms the fixed anchor length, is created by expanding the diameter of the borehole cavity, compacting the surrounding soil and altering the localised soil stress regime. The influence of the expansion process on the load-displacement behaviour of anchors is not well understood. It is not possible to define rigorously the mechanisms by which the anchor transfers the applied load to the soil and as a consequence current design methods are highly empirical. This necessitates extensive testing of all production anchors to assure their in service performance. A detailed investigation of the effect of the compaction process on the load capacity of model compaction anchors has been undertaken. These anchors were tested at field scale stresses in the Peter W Rowe geotechnical centrifuge. The model anchors were installed either vertically, or inclined at 20° to the horizontal, in uniform beds of loose and medium dense air dry Mersey River Sand. The design, development and use of the test equipment is discussed and test results showing the effectiveness of the system are presented. A number of model anchor tests were carried out in sets of two. In the first test the anchor was subjected to in-situ expansion of the fixed length to alter the at-rest soil stress regime in this zone, followed by monotonic loading to failure. In the second test (of the pair) the anchor was subjected only to monotonic loading to failure. These centrifuge tests demonstrated that the ultimate load capacity of the model anchors could be increased by up to 350% as a result of the expansion process. This enhanced capacity is attributed to the increased confinement acting on the surface of the anchor which results in the mobilisation of high bond stresses at the interface between the anchor and the soil as it is displaced to failure. The influence of the grouting pressure on the expansion of the fixed anchor length cavity and the consequent effect of this process on the localised soil stress regime was measured and compared to the response predicted by cavity expansion theory and computed using a finite element analysis. The theoretical estimates show good agreement with the data obtained from the centrifuge tests. Any rational anchor design method should incorporate consideration of the process of progressive debonding. This phenomenon occurs in field scale anchors and governs the distribution of load transfer from the anchor to the soil over the fixed length. The implementation of an analytical model which enables the influence of progressive debonding to be taken into account in the calculation of the ultimate load capacity of anchors is described. The effectiveness of this model has been demonstrated by the close agreement between the predicted and measured load displacement behaviour of field scale anchors.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2024

Mode of access: World Wide Web

ISBN: 9780438138728Subjects--Topical Terms:

561339
Civil engineering.
Subjects--Index Terms:

Compaction anchorsIndex Terms--Genre/Form:

554714
Electronic books.

Modelling of compaction ground anchors.
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504 $a Includes bibliographical references
520 $a Pressure grouting of compaction anchors deployed in granular soils is a widely used construction technique. The grout bulb, which forms the fixed anchor length, is created by expanding the diameter of the borehole cavity, compacting the surrounding soil and altering the localised soil stress regime. The influence of the expansion process on the load-displacement behaviour of anchors is not well understood. It is not possible to define rigorously the mechanisms by which the anchor transfers the applied load to the soil and as a consequence current design methods are highly empirical. This necessitates extensive testing of all production anchors to assure their in service performance. A detailed investigation of the effect of the compaction process on the load capacity of model compaction anchors has been undertaken. These anchors were tested at field scale stresses in the Peter W Rowe geotechnical centrifuge. The model anchors were installed either vertically, or inclined at 20° to the horizontal, in uniform beds of loose and medium dense air dry Mersey River Sand. The design, development and use of the test equipment is discussed and test results showing the effectiveness of the system are presented. A number of model anchor tests were carried out in sets of two. In the first test the anchor was subjected to in-situ expansion of the fixed length to alter the at-rest soil stress regime in this zone, followed by monotonic loading to failure. In the second test (of the pair) the anchor was subjected only to monotonic loading to failure. These centrifuge tests demonstrated that the ultimate load capacity of the model anchors could be increased by up to 350% as a result of the expansion process. This enhanced capacity is attributed to the increased confinement acting on the surface of the anchor which results in the mobilisation of high bond stresses at the interface between the anchor and the soil as it is displaced to failure. The influence of the grouting pressure on the expansion of the fixed anchor length cavity and the consequent effect of this process on the localised soil stress regime was measured and compared to the response predicted by cavity expansion theory and computed using a finite element analysis. The theoretical estimates show good agreement with the data obtained from the centrifuge tests. Any rational anchor design method should incorporate consideration of the process of progressive debonding. This phenomenon occurs in field scale anchors and governs the distribution of load transfer from the anchor to the soil over the fixed length. The implementation of an analytical model which enables the influence of progressive debonding to be taken into account in the calculation of the ultimate load capacity of anchors is described. The effectiveness of this model has been demonstrated by the close agreement between the predicted and measured load displacement behaviour of field scale anchors.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2024
538 $a Mode of access: World Wide Web
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653 $a Compaction anchors
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710 2 $a The University of Manchester (United Kingdom). $b School of Engineering. $3 1478790
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