| 1. |
- Stephansson, Ove, et al.
(author)
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Nuclear power production in an underground chain
- 1984
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In: Rock mechanics. - Rotterdam : Balkema Publishers, A.A. / Taylor & Francis The Netherlands. - 9061912350 ; , s. 1193-1197
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Conference paper (peer-reviewed)
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| 5. |
- Leijon, Bengt A., et al.
(author)
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A comparative study between two rock stress measurement techniques at Luossavaara Mine
- 1986
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In: Rock Mechanics and Rock Engineering. - 0723-2632 .- 1434-453X. ; 19:3, s. 143-163
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Journal article (peer-reviewed)abstract
- As part of a comprehensive geomechanical pre-investigation scheme, rock stress measurements were conducted at four locations, representing three different rock types, in the Luossavaara Mine, located within the Kiruna iron ore fields in northern Sweden. Two similar triaxial overcoring techniques, the CSIRO Hollow Inclusion Technique and the LUH Triaxial Technique, were used in a parallel fashion in order to obtain redundant results, but also with the intention of comparing the field applicability of the two methods. The results show that the state of stress is characterized by a sub-horizontally directed maximum stress with a magnitude of about 10 MPa. The agreement in terms of stress results between the two methods was generally good. The study demonstrated that the technical differences between the two devices used were of little significance as compared to the observed, often non-ideal mechanical characteristics of the rock. The latter added considerable uncertainty to the data, regardless of the measuring technique used, and it is therefore concluded that the rock quality is a major factor in the application of any overcoring method. Finally, it was shown that the biaxial test method, which is frequently used for the determination of rock properties in connection with stress measurements, is not always relevant for this purpose.
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| 6. |
- Li, Chunlin, et al.
(author)
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Analytical models for rock bolts
- 1999
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In: International Journal of Rock Mechanics And Mining Sciences. - 1365-1609 .- 1873-4545. ; 36:8, s. 1013-1029
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Journal article (peer-reviewed)abstract
- Three analytical models have been developed for rock bolts: one for bolts subjected to a concentrated pull load in pullout tests, one for bolts installed in uniformly deformed rock masses, and one for bolts subjected to the opening of individual rock joints. The development of the models has been based on the description of the mechanical coupling at the interface between the bolt and the grout medium for grouted bolts, or between the bolt and the rock for frictionally coupled bolts. For rock bolts in pullout tests, the shear stress of the interface attenuates exponentially with increasing distance from the point of loading when the deformation is compatible across the interface. Decoupling may start first at the loading point when the applied load is large enough and then propagate towards the far end of the bolt with a further increase in the applied load. The magnitude of the shear stress on the decoupled bolt section depends on the coupling mechanism at the interface. For fully grouted bolts, the shear stress on the decoupled section is lower than the peak shear strength of the interface, while for fully frictionally coupled bolts it is approximately the same as the peak shear strength. For rock bolts installed in uniformly deformed rock, the loading process of the bolts due to rock deformation has been taken into account in developing the model. Model simulations confirm the previous findings that a bolt in situ has a pick-up length, an anchor length and a neutral point. It is also revealed that the face plate plays a significant role in enhancing the reinforcement effect. In jointed rock masses, several axial stress peaks may occur along the bolt because of the opening of rock joints intersecting the bolt.
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| 7. |
- Li, Chunlin, et al.
(author)
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Design of underground drainage boreholes in foliated formations
- 1996
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In: Rock Mechanics and Rock Engineering. - 0723-2632 .- 1434-453X. ; 29:2, s. 99-105
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Journal article (peer-reviewed)abstract
- The principle for the design of a directional drainage borehole in a foliated formation is such that the borehole is drilled so that it crosses all the interested foliation planes. If the inclination angle of the borehole is not appropriately selected, the borehole might never reach the concerned foliation planes. In other words, there exists a critical inclination angle for the borehole. The borehole is able to cross the concerned foliation planes only at an inclination angle larger than the critical angle. The critical inclination angle depends on the geological structure of the foliation planes as well as the trend of the drift. The method to determine the critical inclination angle is described both graphically and analytically in this paper. A case for design of drainage boreholes in a copper mine, using the developed method, is also presented
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