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Lindqvist, Per-Arne
Publications (10 of 76) Show all publications
Rai, P., Schunnesson, H., Lindqvist, P.-A. & Kumar, U. (2016). Measurement-while-drilling technique and its scope in design and prediction of rock blasting (ed.). International Journal of Mining Science and Technology, 26(4), 711-719
Open this publication in new window or tab >>Measurement-while-drilling technique and its scope in design and prediction of rock blasting
2016 (English)In: International Journal of Mining Science and Technology, ISSN 2095-2686, Vol. 26, no 4, p. 711-719Article in journal (Refereed) Published
Abstract [en]

With rampant growth and improvements in drilling technology, drilling of blast holes should no longer be viewed as an arduous sub-process in any mining or excavation process. Instead, it must be viewed as an important opportunity to quickly and accurately measure the geo-mechanical features of the rock mass on-site, much in advance of the downstream operations. It is well established that even the slightest variation in lithology, ground conditions, blast designs vis-à-vis geologic features and explosives performance, results in drastic changes in fragmentation results. Keeping in mind the importance of state-of-the-art measurement-while-drilling (MWD) technique, the current paper focuses on integrating this technique with the blasting operation in order to enhance the blasting designs and results. The paper presents a preliminary understanding of various blasting models, blastability and other related concepts, to review the state-of-the-art advancements and researches done in this area. In light of this, the paper highlights the future needs and implications on drill monitoring systems for improved information to enhance the blasting results.

National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering; Operation and Maintenance
Identifiers
urn:nbn:se:ltu:diva-3643 (URN)10.1016/j.ijmst.2016.05.025 (DOI)000383711800025 ()2-s2.0-84990252011 (Scopus ID)175fe9de-b051-4e5e-95c5-3ea84da3d096 (Local ID)175fe9de-b051-4e5e-95c5-3ea84da3d096 (Archive number)175fe9de-b051-4e5e-95c5-3ea84da3d096 (OAI)
Note

Validerad; 2016; Nivå 1; 20160617 (andbra)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Rai, P., Schunnesson, H., Lindqvist, P.-A. & Kumar, U. (2015). An Overview on Measurement-While-Drilling Technique and its Scope in Excavation Industry (ed.). Paper presented at . Journal of The Institution of Engineers (India): Series D, 96(1), 57-66
Open this publication in new window or tab >>An Overview on Measurement-While-Drilling Technique and its Scope in Excavation Industry
2015 (English)In: Journal of The Institution of Engineers (India): Series D, ISSN 2250-2122, Vol. 96, no 1, p. 57-66Article in journal (Refereed) Published
Abstract [en]

Measurement-while-drilling (MWD) aims at collecting accurate, speedy and high resolution information from the production blast hole drills with a target of characterization of highly variable rock masses encountered in sub-surface excavations. The essence of the technique rests on combining the physical drill variables in a manner to yield a fairly accurate description of the sub-surface rock mass much ahead of following downstream operations. In this light, the current paper presents an overview of the MWD by explaining the technique and its set-up, the existing drill–rock mass relationships and numerous on-going researches highlighting the real-time applications. Although the paper acknowledges the importance of concepts of specific energy, rock quality index and a couple of other indices and techniques for rock mass characterization, it must be distinctly borne in mind that the technique of MWD is highly site-specific, which entails derivation of site-specific calibration with utmost care.

National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering; Operation and Maintenance
Identifiers
urn:nbn:se:ltu:diva-4315 (URN)10.1007/s40033-014-0054-4 (DOI)2-s2.0-84952928229 (Scopus ID)23e841fe-da5c-483f-adc5-21cc3efb725f (Local ID)23e841fe-da5c-483f-adc5-21cc3efb725f (Archive number)23e841fe-da5c-483f-adc5-21cc3efb725f (OAI)
Note
Godkänd; 2015; 20141113 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Liu, H., Lindqvist, P.-A., Åkesson, U., Kou, S. & Lindqvist, J.-E. (2012). Characterisation of rock aggregate breakage properties using realistic texture-based modelling (ed.). International journal for numerical and analytical methods in geomechanics (Print), 36(10), 1280-1302
Open this publication in new window or tab >>Characterisation of rock aggregate breakage properties using realistic texture-based modelling
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2012 (English)In: International journal for numerical and analytical methods in geomechanics (Print), ISSN 0363-9061, E-ISSN 1096-9853, Vol. 36, no 10, p. 1280-1302Article in journal (Refereed) Published
Abstract [en]

Realistic texture-based modelling methods, that is microstructural modelling and micromechanical modelling, are developed to simulate the rock aggregate breakage properties on the basis of the rock actual microstructure obtained using microscopic observations and image analysis. The breakage properties of three types of rocks, that is Avja, LEP and Vandle taken from three quarries in Sweden, in single aggregate breakage tests and in inter-aggregate breakage tests are then modelled using the proposed methods. The microstructural modelling directly integrates the microscopic observation, image analysis and numerical simulation together and provides a valuable tool to investigate the mechanical properties of rock aggregates on the basis of their microstructure properties. The micromechanical modelling takes the most important microstructure properties of rock aggregates into consideration and can model the major mechanical properties. Throughout this study, it is concluded that in general, the microstructure properties of rock aggregate work together to affect their mechanical properties, and it is difficult to correlate a single microstructure property with the mechanical properties of rock aggregates. In particular, for the three types of rock Avja, LEP and Vandle in this study, crack size distribution, grain size and grain perimeter (i.e. grain shape and spatial arrangement) show good correlations with the mechanical properties. The crack length and the grain size negatively affect the mechanical properties of Avja, LEP and Vandle, but the perimeter positively influences the mechanical properties. Besides, the modelled rock aggregate breakage properties in both single aggregate and inter-aggregate tests reveal that the aggregate microstructure, aggregate shape and loading conditions influence the breakage process of rock aggregate in service. For the rock aggregate with the same microstructure, the quadratic shape and good packing dramatically improve its mechanical properties. During services, the aggregate is easiest to be fragmented under point-to-point loading condition, and then in the sequence of multiple-point, point-to-plane and plane-to-plane loading conditions

National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-14349 (URN)10.1002/nag.1053 (DOI)000305680500003 ()2-s2.0-84862906319 (Scopus ID)db38b3b8-f01c-479e-8a06-81973fcc6150 (Local ID)db38b3b8-f01c-479e-8a06-81973fcc6150 (Archive number)db38b3b8-f01c-479e-8a06-81973fcc6150 (OAI)
Note

Validerad; 2012; 20110617 (andbra)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Liu, H., Lindqvist, P.-A., Åkesson, U., Kou, S. & Lindqvist, J. (2011). Characterization of rock properties using texture-based modelling: a geometallurgical approach (ed.). In: (Ed.), Johanna Alatalo (Ed.), Conference in Mineral Engineering: Luleå, 8-9 February 2011. Paper presented at Konferens i mineralteknik 2011 : 08/02/2011 - 09/02/2011. Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>Characterization of rock properties using texture-based modelling: a geometallurgical approach
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2011 (English)In: Conference in Mineral Engineering: Luleå, 8-9 February 2011 / [ed] Johanna Alatalo, Luleå: Luleå tekniska universitet, 2011Conference paper, Published paper (Other academic)
Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2011
National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-39616 (URN)e71a1f25-beea-4387-b866-af891307137b (Local ID)978-91-7439-220-3 (ISBN)e71a1f25-beea-4387-b866-af891307137b (Archive number)e71a1f25-beea-4387-b866-af891307137b (OAI)
Conference
Konferens i mineralteknik 2011 : 08/02/2011 - 09/02/2011
Note

Godkänd; 2011; 20110414 (andbra)

Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2018-03-20Bibliographically approved
Zhang, Z., Lindqvist, P.-A., Naarttijärvi, T. & Wikström, K. (2010). A feasibility study on controlling ground vibrations caused by blasts in Malmberget underground mine (ed.). Fragblast, 8(1), 3-21
Open this publication in new window or tab >>A feasibility study on controlling ground vibrations caused by blasts in Malmberget underground mine
2010 (English)In: Fragblast, ISSN 1385-514X, E-ISSN 1744-4977, Vol. 8, no 1, p. 3-21Article in journal (Refereed) Published
Abstract [en]

In order to control or reduce the ground vibrations caused by underground blasts in Malmberget mine, a number of blast tests were carried out during production blasts and a series of single shot waveforms were obtained. Then the single shot waveforms from the same ring or different rings were analysed and compared with each other. The results showed that the single shots are reproducible, meaning that the ground vibrations caused by underground blasts can be controlled by means of the interference of the vibration waveforms measured. Finally, a formal test using electronic detonators and employing an optimum delay time of 8 ms was done in production. The test for an 11-borehole ring shows that the maximum vertical ground vibrations are reduced to the maximum vertical vibrations of a single shot. Particularly, the total vibration history for the 11-borehole-ring blast is shortened to about 200 ms over a velocity of 2 mm/s. However, the total vibration history of a normal production blast of 11-borehole ring is always 1400 ms over a velocity of 2 mm/s, namely the total vibration time of a production blast can be reduced to one seventh of that of the common production blasts by using the vibration control method. This indicates that the vibration control method introduced in the paper is feasible for underground mining blasts

Keywords
Civil engineering and architecture - Geoengineering and mining engineering, Samhällsbyggnadsteknik och arkitektur - Geoteknik och gruvteknik
National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-9457 (URN)10.1080/13855140512331389604 (DOI)818dc0a0-2aa7-11df-be83-000ea68e967b (Local ID)818dc0a0-2aa7-11df-be83-000ea68e967b (Archive number)818dc0a0-2aa7-11df-be83-000ea68e967b (OAI)
Note

Validerad; 2010; 20100308 (andbra)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-03-20Bibliographically approved
Liu, H., Kou, S. & Lindqvist, P.-A. (2008). Numerical studies on bit-rock fragmentation mechanisms (ed.). Paper presented at . International Journal of Geomechanics, 8(1), 45-67
Open this publication in new window or tab >>Numerical studies on bit-rock fragmentation mechanisms
2008 (English)In: International Journal of Geomechanics, ISSN 1532-3641, E-ISSN 1943-5622, Vol. 8, no 1, p. 45-67Article in journal (Refereed) Published
Abstract [en]

The rock fragmentation process induced by a single button-bit, two neighboring button-bits, and multiple button-bits are numerically studied using the rock and tool interaction code (R-T2D). Through this study, a better understanding of the bit-rock fragmentation mechanisms is gained. It is found that side crack is initiated from the crushed zone or bifurcated from Hertzian crack to propagate approximately parallel to the free rock surface but in a curvilinear path driven by the tensile stress associated with the expansion of the crushed zone during the loading process. In the crushed zone, the mechanism of side crack is mixed tensile and shear failure, but outside the crushed zone, the dominant mechanism of side crack is tensile failure. A semiempirical and semitheoretical relationship among the side crack length, the drilled rock property, and the drilling force is formulated to approximately predict the side crack length. In the simultaneous loading, the interaction and coalescence of side cracks induced by the neighboring button-bits with an optimum line spacing enable formation of largest rock chips, control of the direction of subsurface cracks and a minimum total specific energy consumption. A formula is derived to determine the optimum line spacing on the basis of the drilled rock properties, the diameter and shape of the button-bit, and the drilling conditions. In the rock fragmentation by multiple button-bits, most of the rock between the neighboring button-bits is chipped as a result of the coalescence of side cracks. In the remaining rock, the intensely crushed zones and significant extensional cracks are observed adjacent to the sidewall and the inside of the borehole. Fragment side distribution shows more than 80% of the fragments are fines in the crushed zones as well as the cracked zones, the large fragments be indeed observed, which are the big chips caused by the coalescence of side cracks.

Keywords
Civil engineering and architecture - Geoengineering and mining engineering, Samhällsbyggnadsteknik och arkitektur - Geoteknik och gruvteknik
National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-13814 (URN)10.1061/(ASCE)1532-3641(2008)8:1(45) (DOI)000209489500007 ()2-s2.0-38349006849 (Scopus ID)d1a71cf0-2b24-11dd-8657-000ea68e967b (Local ID)d1a71cf0-2b24-11dd-8657-000ea68e967b (Archive number)d1a71cf0-2b24-11dd-8657-000ea68e967b (OAI)
Note
Validerad; 2008; 20080526 (cira)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Miskovsky, K., Duarte, M. T., Kou, S. & Lindqvist, P.-A. (2007). Influence of the mineralogical composition and textural properties on the quality of coarse aggregates (ed.). In: (Ed.), (Ed.), 2007 General Assembly of the European Geosciences Union, Vienna (Austria), 15-20 Apr 2007: . Paper presented at General Assembly of the European Geosciences Union : 15/04/2007 - 20/04/2007. : European Geosciences Union (EGU)
Open this publication in new window or tab >>Influence of the mineralogical composition and textural properties on the quality of coarse aggregates
2007 (English)In: 2007 General Assembly of the European Geosciences Union, Vienna (Austria), 15-20 Apr 2007, European Geosciences Union (EGU), 2007Conference paper, Meeting abstract (Other academic)
Place, publisher, year, edition, pages
European Geosciences Union (EGU), 2007
National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-28322 (URN)21709d20-40f0-11dd-8634-000ea68e967b (Local ID)21709d20-40f0-11dd-8634-000ea68e967b (Archive number)21709d20-40f0-11dd-8634-000ea68e967b (OAI)
Conference
General Assembly of the European Geosciences Union : 15/04/2007 - 20/04/2007
Note
Godkänd; 2007; 20080623 (andbra)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
Liu, H. Y., Kou, S. Q., Lindqvist, P.-A. & Tang, C. A. (2007). Numerical modelling of the heterogeneous rock fracture process using various test techniques (ed.). Paper presented at . Rock Mechanics and Rock Engineering, 40(2), 107-144
Open this publication in new window or tab >>Numerical modelling of the heterogeneous rock fracture process using various test techniques
2007 (English)In: Rock Mechanics and Rock Engineering, ISSN 0723-2632, E-ISSN 1434-453X, Vol. 40, no 2, p. 107-144Article in journal (Refereed) Published
Abstract [en]

A series of numerical tests including both rock mechanics and fracture mechanics tests are conducted by the rock and tool (R-T2D) interaction code coupled with a heterogeneous masterial model to obtain the physical-mechanical properties and fracture toughness, as well as to simulate the crack initiation and propagation, and the fracture progressive process. The simulated results not only predict relatively accurate physical-mechanical parameters and fracture toughness, but also visually reproduce the fracture progressive process compared with the experimental and theoretical results. The detailed stress distribution and redistribution, crack nucleation and initiation, stable and unstable crack propagation, interaction and coalescence, and corresponding load-displacement curves can be proposed as benchmarks for experimental study and theoretical research on crack propagation. It is concluded that the heterogeneous material model is reasonable and the R-T2D code is stable, repeatable and a valuable numerical tool for research on the rock fracture process.

National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-5104 (URN)10.1007/s00603-006-0091-x (DOI)000245363300001 ()2-s2.0-34047111392 (Scopus ID)3207b180-6b46-11dc-9e58-000ea68e967b (Local ID)3207b180-6b46-11dc-9e58-000ea68e967b (Archive number)3207b180-6b46-11dc-9e58-000ea68e967b (OAI)
Note
Validerad; 2007; 20070925 (bajo)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Li, L., Tang, C., Tang, S. & Lindqvist, P.-A. (2006). Damage coupled thermo-mechanical model for rock failure process and applications (ed.). Paper presented at . Acta Mechanica Sinica, 38(4), 505-513
Open this publication in new window or tab >>Damage coupled thermo-mechanical model for rock failure process and applications
2006 (Chinese)In: Acta Mechanica Sinica, ISSN 0567-7718, E-ISSN 0459-1879, Vol. 38, no 4, p. 505-513Article in journal (Refereed) Published
Abstract [en]

Based on the heterogeneous characteristics of rock at mesoscopic level, the thermo-mechanical (TM) coupled behavior during the failure process of rock subjected to thermal stress is analyzed with elastic damage mechanics and thermo-elastic theory. A mesoscopic TM coupling model, implemented in rock fracture process analysis (RFPA), is proposed, which can be used to study the damage and failure process, as well as elastic stress for the coupled TM rock problem. With the numerical model, the damage and associated mechanical properties evolution of mesoscopic structure in rocks subjected to TM loading can be analyzed. Numerical simulation is carried out to investigate the stability of the rock pillar in a hard rock laboratory. The numerically obtained stress field, failure pattern of pillar rock and associated acoustic emission (AE) events all agree well with the in-situ data, which shows that the proposed model is reasonable and effective, and may provide guides for the experiment design and associated applications

National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-6007 (URN)433508b0-a093-11df-a707-000ea68e967b (Local ID)433508b0-a093-11df-a707-000ea68e967b (Archive number)433508b0-a093-11df-a707-000ea68e967b (OAI)
Note
Godkänd; 2006; 20100805 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Li, L., Tang, C. & Lindqvist, P.-A. (2006). Fracture Behavior in a Rock Pillar Subjected to Coupled Thermo-Mechanical Loading (ed.). Paper presented at International Conference on Fracture and Damage Mechanics : 13/09/2006 - 15/09/2006. Key Engineering Materials, 324/325, 443-446
Open this publication in new window or tab >>Fracture Behavior in a Rock Pillar Subjected to Coupled Thermo-Mechanical Loading
2006 (English)In: Key Engineering Materials, ISSN 1013-9826, E-ISSN 1662-9795, Vol. 324/325, p. 443-446Article in journal (Refereed) Published
Abstract [en]

Using RFPA code, analyses have been carried out to investigate the stability of a rock pillar in a experiment for nuclear waste repositories, the numerically obtained stress field, temperature distribution, failure pattern of the pillar rock and associated AE events are all agree well with the in-situ data. Minor fracture initiation may take place in the vicinity of the boreholes after heating. Heating induces minor spalling at central pillar wall for 0.5 m sections below the tunnel floor, but the area of spalling is found to be limited. The core of the pillar remains intact for stress conditions corresponding to 120 days of heating which not only prove that the proposed technique provides a powerfully alternative and effective approach for the study on thermal-mechanical-damage coupling mechanism but also provide meaningful guides for the experiment design and associated applications.

National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-27778 (URN)10.4028/www.scientific.net/KEM.324-325.443 (DOI)2-s2.0-33750913189 (Scopus ID)15075e60-5cd8-11df-ab16-000ea68e967b (Local ID)15075e60-5cd8-11df-ab16-000ea68e967b (Archive number)15075e60-5cd8-11df-ab16-000ea68e967b (OAI)
Conference
International Conference on Fracture and Damage Mechanics : 13/09/2006 - 15/09/2006
Note

Godkänd;2006;20100511 (andbra);Konferensartikel i tidskrift;Bibliografisk uppgift: Volumne: 324-325

Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-12-14Bibliographically approved
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