| 1. |
- Arvanitidis, Ioannis, et al.
(författare)
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Diameterns inverkan på detonationsegenskaperna hos emulsionssprängämne E682 i cylinderprovet
- 2004
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Cylinder expansions tests with 4 different diameters ranging from 40 to 100 mm have been conducted on the generic emulsion explosive E682, both pure and with 20 % ANFO content. The work capacity is expressed in terms of the Gurney energy EG, which equals the sum of the kinetic energy of the copper tube and the radial kinetic energy of the gases. The purpose was to study the effect of charge diameter on the explosive's work capacity expressed as the Gurney energy and to supplement earlier work done by Nie (2001). The radial expansion has been measured as well as the velocity of detonation in 11 copper tubes. The effect of ANFO granules were tested by making a mixture of E682 with 20% ANFO. The ANFO used in the present study is Anolit from Dyno Nobel, which basically is the same product as the Prillit A used by Nie. The average density of pure E682 was 1130 kg/m3 and that of E682 with 20% ANFO 1200 kg/m3. The results from the new batch of E682 show similarities with the old batch regarding VOD as function of inverse charge diameter but the trend of the Gurney energy is different from the first experiments carried out by Nie. This could be due to previous tolerance variations in the tube dimensions. The Gurney energy seems to be independent of the charge diameter between 40-100 mm in the new experiments. The measured Gurney energy for pure E682 was 1.77 ± 0.06 MJ/kg and that of E682 with 20% ANFO 1.71 ± 0.07 MJ/kg which is somewhat lower. The use of 20% ANFO in E682 results in the same volume based Gurney energy as for pure E682 however. The overall average is 2.02 ± 0.02 MJ/dm3. The energy utilisation ratio is 0.58 ± 0.03 for pure E682 and 0.53 ± 0.03 for E682 with 20% ANFO. This is slightly lower than for the Titan 6000 series gassed bulk emulsion but higher than for pure ANFO. The detonation pressure decreases with the charge diameter however and this indicates that a smaller hole diameter in rock blasting leads to a lower detonation pressure without loosing work energy when keeping the powder factor constant.
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| 3. |
- Jing, Lanru, et al.
(författare)
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Fundamentals of the hydro-mechanical behaviour of rock fractures : roughness characterization and experimental aspects
- 2004
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Ingår i: International Journal of Rock Mechanics And Mining Sciences. - : Elsevier BV. - 1365-1609 .- 1873-4545. ; 41:3, s. 383-383
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Tidskriftsartikel (refereegranskat)abstract
- The coupled hydro-mechanical behaviour of rock fractures plays an important role in design, performance and safety assessments of rock engineering projects. However, due to the complexity in the mathematical representation of the fracture surface geometry and its effects on the stress-flow behaviour of the fractures, and the limitations in the test conditions in laboratories, significant lack of knowledge still exists in testing and modelling approaches regarding rock fractures. Based on a general review of the roughness characterization and shear-flow testing of rock fractures, this paper presents the definition of the stationarity threshold of roughness, and a combined experimental-numerical approach for simulating rock fracture testing conditions for more general fluid flow behaviour of the rock fractures. The conclusions are that fracture roughness characterization must be conducted and represented in three-dimensions and the more general fluid flow behaviour cannot be observed with conventional parallel shear-flow tests or compressionradial flow tests. Numerical simulations are needed to reveal more general behaviour of stress-flow processes of rock fractures with boundary and loading conditions that are difficult or impractical in laboratory tests.
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| 4. |
- Li, Chunlin
(författare)
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Deformation Modulus Of Jointed Rock Masses In Three-Dimensional Space
- 2000
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Ingår i: ISRM International Symposium 2000. - : International Society for Rock Mechanics.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In jointed rock masses deformability is associated with the mechanical properties of the intact rock and the rock joints. It is also known that the deformation modulus of jointed rock masses is anisotropic because of the presence of rock joints. This paper presents an analytical approach to the estimation of the deformation modulus of rock masses that contain any number of single joints or joint sets. The data needed for calculation are the elastic parameters of the intact rock, the orientations of the joints and the stiffness of the joints. The deformation modulus of the rock mass calculated in three-dimensional space can be plotted in a hemispherical diagram. From this diagram one can find the value of the deformation modulus in any given direction and even an estimate of the average overall modulus.
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| 5. |
- Lundholm, Beatrice, et al.
(författare)
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The Effect Of Overcoring On Elastic Properties And Evaluated Stress Components
- 2000
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Ingår i: ISRM International Symposium 2000. - : International Society for Rock Mechanics.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The influence of Poisson"s ratio on overcoring was investigated using data from 47 tests. In these tests both the CSIRO HI triaxial cell and the triaxial cell developed by Swedish State Power Board were used. Boreholes drilled parallel to the major principal stress resulted in higher Poisson"s ratio compared to boreholes drilled at an angle to major principal stress. Numerical modelling by FLAC was used to simulate overcoring and biaxial testing. When the major principal stress is acting perpendicular to the borehole, the extensional strain is larger on the inner surface of the core during overcoring than when parallel to the borehole. Simulations of a biaxial test of a virgin core show extensional strain, which may be larger than critical extensional strain of the rock type, indicating non-elastic behaviour.
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| 10. |
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VTI:s och KFB:s forskardagar : del 2
- 2000
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Proceedings (redaktörskap) (övrigt vetenskapligt/konstnärligt)abstract
- Rapportsammanställning av föredrag vid forskardagarna i Linköping 2000:EU-projektet ALT-MAT - redovisning av resultattrafik och miljöprojektbilismen i ett kulturellt perspektivtema nedbrytning av vägtema upphandlingtema vägyta-trafikeffektertema infrastrukturens sårbarhetjämförelse mellan olika lösningarhälsoeffekter och attityderolika åtgärder i vägtrafiken - möjligheter och effekterväginformatik - nya perspektiv och aktuella insatser
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| 11. |
- Zimmerman, R.W., et al.
(författare)
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Non-linear regimes of fluid flow in rock fractures
- 2004
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Ingår i: International Journal of Rock Mechanics And Mining Sciences. - : Elsevier BV. - 1365-1609 .- 1873-4545. ; 41:3, s. 384-384
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Tidskriftsartikel (refereegranskat)abstract
- We have conducted high-resolution Navier-Stokes simulations and laboratory measurements of fluid flow in a natural sandstone fracture. First, epoxy casts were made of the two opposing fracture surfaces. The surface profiles of the two surfaces were then measured at a vertical resolution of ±2 μm, every 20 μm in the x and y-directions, over 2 cm × 2 cm regions of the fracture. These data were then used to create a finite-element mesh for the fracture void space, and the Navier-Stokes equations were solved within this domain. Flow experiments were also conducted within the same fracture casts, over a range of flowrates. The simulations confirm the existence of a weak inertia regime for Reynolds numbers in the range of 1-10, in which the non-Darcy pressure drop varies with the cube of the flowrate. Although of theoretical interest, this effect is, however, probably too small to be of engineering interest. At Reynolds numbers above about 20, both the simulations and experiments exhibit a Forchheimer-type regime, in which the non-Darcy pressure drop is quadratic in the flowrate.
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