Rock Anchors Research Articles

Laboratory and field evaluation of the bonding strength of grouted rock anchors : Ballivy, G; Dupuis, M In: Underground Rock Engineering (Papers to 13th Canadian Rock Mechanics Symposium, Toronto, 28–29 May 1980), P97–102. Publ Montreal: CIMM, 1980

Laboratory and field evaluation of the bonding strength of grouted rock anchors : Ballivy, G; Dupuis, M In: Underground Rock Engineering (Papers to 13th Canadian Rock Mechanics Symposium, Toronto, 28–29 May 1980), P97–102. Publ Montreal: CIMM, 1980

Practical Considerations in Tieback Construction

The advantages and disadvantages of tieback supported cofferdams as opposed to conventionally-braced systems are reviewed. Different procedures and considerations in tieback construction are presented. Cost analysis is considered, as well as equipment and techniques. The different types of tiebacks now commonly used are presented. Rock, earth, and regroutable anchors are analysed, along with their application, design, installation procedure, advantages and disadvantages. Varying soil strata, drilling techniques, installation, equipment, grouting methods and structural elements are analyzed.

Rock anchors: An outline of some current design, construction and testing practices in the United Kingdom : Turner, M J Proc International Conference on Structural Foundations on Rock, Sydney, 7–9 May 1980, P87–103. Publ Rotterdam: A A Balkema, 1980

The methods of design, construction and testing developed over a number of rock anchor contracts, which are generally typical of the mainstream of British rock anchor development over the last few years, are described. Without doubt the trend is towards more sophisticated techniques in the prevention of corrosion and in the ability to monitor, check and adjust the load within the anchor tendon over its design life. Of major importance in design is the choice of a realistic value for the bond at the grout to rock interface, and some values derived from a number of test anchors are quoted for consideration.

Design and construction of foundations for bridges on the Kuantan to Segamat Highway, Malaysia : Kemp, G J; Chew, S H Proc International Conference on Structural Foundations on Rock, Sydney, 7–9 May 1980, P271–281. Publ Rotterdam: A A Balkema, 1980

This paper details the sub-surface investigations, design considerations and construction techniques associated with two bridges, namely the bridges over the keratong and rompin rivers. The 250 m long prestressed concrete bridge over the keratong river was designed to be overtopped during floods of large return period. Under such conditions and under some live load conditions tension could be induced into the precast concrete pier piles. In some locations, these piles were founded on fresh granite some 9 m below the pile cap and after allowing for some scour had insufficient penetration to provide adequate resistance against uplift. For this reason, the driven square precast reinforced concrete tension piles for the piers were cast with a central circular duct and after driving to bedrock and capped were post- tensioned to the bed- rock and grouted, using prestressed rock anchors. The 330 m long rompin river bridge was designed to be submersible and carried similar loads to those of the keratong river and as well was required to straddle a highly faulted rock zone which generally followed the course of the river in the vicinity of the bridge sito. The highly fragmented and crushed rock along the fault line had low bearing and tensile capacities and the piers supporting the main channel span of the bridge had to be founded on this crushed igneous and sedimentary rock.

Design and installation of rock anchors in granite gneiss for foundation stabilisation : Daws, G Proc International Conference on Structural Foundations on Rock, Sydney, 7–9 May 1980, P105–108. Publ Rotterdam: A A Balkema, 1980

Design and installation of rock anchors in granite gneiss for foundation stabilisation : Daws, G Proc International Conference on Structural Foundations on Rock, Sydney, 7–9 May 1980, P105–108. Publ Rotterdam: A A Balkema, 1980

Toppling rock slope failures examples of analysis and stabilization

Toppling Rock Slope Failures — Examples of Analysis and Stabilization Three case histories of toppling failures of rock slopes, and the methods used to ensure that failure did not disrupt operations below the slope, are described. The application of Goodman and Bray's limit equilibrium analysis of multi-block failures to these three slopes is demonstrated. The first failure occurred in a 20 m high granite slope that was stabilized by removing the top 6 m and installing a number of tensioned rock anchors in the toe. The second failure occurred in a sequence of folded sandstone, shale and coal. This slide was too large to stabilize, so the movement rate was monitored while mining continued in the pit below until shortly before failure took place. In the third failure, the top 8 m of a single 12 m high toppling block was removed by blasting to prevent further rotational movement.

Onorm B 4455: Prestressed anchors in soft soil and rock (in German) : Seltenhammer, U Rock Mech, Suppl 8, 1979, P287–290 (paper to 27th Geomechanical Colloquium, Austrian Society for Geomechanics, Salzburg, 12–13 Oct 1978)

Onorm B 4455: Prestressed anchors in soft soil and rock (in German) : Seltenhammer, U Rock Mech, Suppl 8, 1979, P287–290 (paper to 27th Geomechanical Colloquium, Austrian Society for Geomechanics, Salzburg, 12–13 Oct 1978)

Contribution to the calculation and optimization of rock anchors in tunnelling (in German) : Seeber, G; Keller, S Rock Mech, Suppl 8, 1979, P59–74 (paper to 27th Geomechanical Colloquium, Austrian Society for Geomechanics, Salzburg, 12–13 Oct 1978)

Contribution to the calculation and optimization of rock anchors in tunnelling (in German) : Seeber, G; Keller, S Rock Mech, Suppl 8, 1979, P59–74 (paper to 27th Geomechanical Colloquium, Austrian Society for Geomechanics, Salzburg, 12–13 Oct 1978)

Rock anchors in underground excavations and their durability (in German) : Herbst, T F; Kern, G Proc 4th Congress International Society for Rock Mechanics, Montreux, 2–8 Sept 1979, Vol 1, P441–449. Publ Rotterdam, A A Balkema, 1979

Rock anchors in underground excavations and their durability (in German) : Herbst, T F; Kern, G Proc 4th Congress International Society for Rock Mechanics, Montreux, 2–8 Sept 1979, Vol 1, P441–449. Publ Rotterdam, A A Balkema, 1979

Long term performance of high capacity rock anchors at devonport : Littlejohn, G S Ground Engng, V12, N7, Oct 1979, P25–33

Long term performance of high capacity rock anchors at devonport : Littlejohn, G S Ground Engng, V12, N7, Oct 1979, P25–33

Behavior of Anchored Foundations Subject to Shear and Moment Loads

The behaviour of a rock anchor cluster under shear and moment loads was investigated by full-scale field tests. These tests showed a complex failure mechanism in rock which varied with the combination of loading. Using simplifying assumptions a theory is proposed to predict the ultimate resistance of the anchor group against rock failure. A simplified procedure is outlined for designing the rock anchored footings for steel pole type transmission structures.

Some results concerning the viscoelastic relaxation of prestress in a surface rock anchor : Selvadurai, A P S Int J Rock Mech Min Sci, V16, N5, Oct 1979, P309–317

Some results concerning the viscoelastic relaxation of prestress in a surface rock anchor : Selvadurai, A P S Int J Rock Mech Min Sci, V16, N5, Oct 1979, P309–317

Corrosion protection and lateral displacement characteristics of rock anchors : Fine, H; Slater, W; Sage, R CANMET report 77-56, Dec 1977, 28P

Corrosion protection and lateral displacement characteristics of rock anchors : Fine, H; Slater, W; Sage, R CANMET report 77-56, Dec 1977, 28P

Some results concerning the viscoelastic relaxation of prestress in a surface rock anchor

This paper investigates the axisymmetric interactive behaviour of a rigid circular plate anchored to a half spaceregion susceptible to creep. The anchoring load corresponds to a distribution of Mindlin type forces, of finite length, located along the axis of symmetry. The creep behaviour of the halfspace region is represented by a linear viscoelastic material with elastic dilatational behaviour and distortional behaviour of the three-parameter solid type. Using this particular idealization, solutions are developed for the loss of prestress in an anchor bolt subjected to a displacement which is a step function of time. The prestress load at the anchor region is assumed to be distributed in a uniform, linear or parabolic fashion. The numerical results presented herein illustrate the manner in which the decay of the prestress load can be influenced by the length, depth of location and load distribution in the anchor region and the creep characteristics of the halfspace region.

Uplift Capacity of Rock Anchor Groups

The uplift capacity of rock anchor groups was examined by full- scale field tests in different rock formations. The results are analyzed and the different modes of failure are discussed in view of the test results with emphasis on the rock pull-up failure mechanism. Important design parameters are summarized for the convenient use of the engineer in the design of transmission tower foundations anchored in bedrock.

Long-term surveillance on rock anchors by means of hydraulic load cells : Dietrich, H Proc International Symposium on Field Measurements in Rock Mechanics, Zurich, 4–6 April 1977, V1, P345–350. Publ Rotterdam: A A Balkema, 1977

Long-term surveillance on rock anchors by means of hydraulic load cells : Dietrich, H Proc International Symposium on Field Measurements in Rock Mechanics, Zurich, 4–6 April 1977, V1, P345–350. Publ Rotterdam: A A Balkema, 1977

The displacement of a rigid circular foundation anchored to an isotropic elastic half-space

This Paper examines the axisyrnmetric problem of a rigid circular foundation, resting on an isotropic elastic half-space which is subjected, simultaneously, to an external load and an internal anchor load. The anchor load consists of constant, linear or parabolic distributions of Mindlin forces of finite length, located along the axis of symmetry. A Mindlin force is defined as a concentrated force which acts at an interior point of the half-space along the axis of symmetry. The solution for the rigid displacement experienced by the circular plate is obtained in an exact closed form. This particular problem is of interest in connection with the study of rock anchors and in the examination of in situ tests such as the cable method of in situ testing. Cet article examine en axisymétric le cas d'une fondation circulaire rigide reposant sur un semi-espace élastique isotrope, soumise simultanément à un effort externe et à un effort d'ancrage interne. L'effort d'ancrage se compose des forces de Mindlin de longueur finie, sitées le long de l'axe de symétrie et dont la répartition est constante, linéaire ou parabolique. Une force Mindlin se définit comme étant une force concentrée agissant en un point interne du semi-espace le long de l'axe de symétrie. On traite le déplacement rigide de la plaque circulaire grâce à l'emploi d'une forme exacte fermée. Ce problème spécifique présente un intérêt pour l'étude des ancrages en terrain rocheux et l'analyse d'essais in situ tels que l'essai utilisant la méthode par câble.

Rock Anchor System for Securing Failing Wall

A description of the design, installation, and testing of 132 permanent rock anchors used by the Pennsylvania Department of Transportation to save a failing concrete retaining wall. Design parameters of the three level rock tieback system are examined along with installation techniques and special corrosion protection used to make the system permanent. Grouting techniques and grout mixes are examined. Recommendations are made against the use of admixtures in the grout. Load testing and load cell monitoring of the anchors show some initial movements but achieve stability in a short period of time.

Mechanical anchor for use in soft or highly fissured ground : Ground Engng, V11, N1, Jan 1978, P23–25

In this article the author describes 40mm diameter mechanical anchors that have been designed specifically to function in the weaker rocks similar to the chalk encountered at Chinnor. The self-under-reaming reversed expanding (SURE) rock anchor has segments which expand over a cone in the reverse direction to a conventional anchor until locked between the cone and a cup. The radial force applied to the ground by the SURE anchor acts inwards, the rock is drawn into the path of the anchor and its ability to resist the load applied is enhanced. The SURE Anchor was designed for use in soft or high fissured ground where existing anchors may not develop adequate loads. The anchor was originally developed for chalk, however its use could be extended to other weak rocks as well as in artificial materials such as poor concrete. In very bad ground it is possible to distribute the load applied to the ground as does a resin anchor, by stacking anchors. Although the SURE anchor was designed with a nominal 40 mm retracted diameter, the design could be adapted to a greater diameter. A larger version can be designed to open to a proportionately greater span and withstand a 90kn load before failure of the steel. The cost of the SURE anchor is more than the conventional mechanism anchor, however the SURE anchor is designed to function in weak rock, alternative methods of suport in such circumstances, using concrete or steelwork would be more expensive.

Use of rock anchors at tarbela : Int Water Power Dam Constr, V30, N2, Feb 1978, P44–47

Use of rock anchors at tarbela : Int Water Power Dam Constr, V30, N2, Feb 1978, P44–47