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Malmgren, Lars
Publications (10 of 21) Show all publications
Shirzadegan, S., Nyberg, U., Zhang, P., Nordlund, E., Malmgren, L., Nordqvist, A. & Andersson, U. B. (2013). Large-scale dynamic testing of ground support system at the Kiirunavaara underground mine: Test 1 (ed.). Paper presented at . Luleå tekniska universitet
Open this publication in new window or tab >>Large-scale dynamic testing of ground support system at the Kiirunavaara underground mine: Test 1
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2013 (English)Report (Other academic)
Place, publisher, year, edition, pages
Luleå tekniska universitet, 2013
National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-23831 (URN)8987fb62-1dbf-4f1d-998a-e82065f1d46a (Local ID)8987fb62-1dbf-4f1d-998a-e82065f1d46a (Archive number)8987fb62-1dbf-4f1d-998a-e82065f1d46a (OAI)
Note

För godkännande; 2013; 20130419 (shashi)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Shirzadegan, S., Nyberg, U., Zhang, P., Nordlund, E., Malmgren, L., Nordqvist, A. & Andersson, U. B. (2013). Large-scale dynamic testing of ground support system at the Kiirunavaara underground mine: Tests 4 & 5 (ed.). Paper presented at . Luleå tekniska universitet
Open this publication in new window or tab >>Large-scale dynamic testing of ground support system at the Kiirunavaara underground mine: Tests 4 & 5
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2013 (English)Report (Other academic)
Place, publisher, year, edition, pages
Luleå tekniska universitet, 2013
National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-24951 (URN)d313ef9b-0f15-4697-9ab8-2ea589f2c6bb (Local ID)d313ef9b-0f15-4697-9ab8-2ea589f2c6bb (Archive number)d313ef9b-0f15-4697-9ab8-2ea589f2c6bb (OAI)
Note

För godkännande; 2013; 20130419 (shashi)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Shirzadegan, S., Nyberg, U., Zhang, P., Nordlund, E., Malmgren, L., Töyrä, J., . . . Andersson, U. B. (2013). Large-scale dynamic testing of ground support system at the Kiirunavaara underground mine: Tests 6&7 (ed.). Paper presented at . Luleå tekniska universitet
Open this publication in new window or tab >>Large-scale dynamic testing of ground support system at the Kiirunavaara underground mine: Tests 6&7
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2013 (English)Report (Other academic)
Place, publisher, year, edition, pages
Luleå tekniska universitet, 2013
National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-24288 (URN)a5c7b9ff-a2e5-4f23-81b5-1f9a26b5c22a (Local ID)a5c7b9ff-a2e5-4f23-81b5-1f9a26b5c22a (Archive number)a5c7b9ff-a2e5-4f23-81b5-1f9a26b5c22a (OAI)
Note

För godkännande; 2013; 20130419 (shashi)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Shirzadegan, S., Nyberg, U., Zhang, P., Nordlund, E., Malmgren, L., Nordqvist, A. & Andersson, U. B. (2013). Large-scale dynamic testing of rock support system at the Kiirunavaara underground mine: Tests 2 & 3 (ed.). Paper presented at . Luleå tekniska universitet
Open this publication in new window or tab >>Large-scale dynamic testing of rock support system at the Kiirunavaara underground mine: Tests 2 & 3
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2013 (English)Report (Other academic)
Place, publisher, year, edition, pages
Luleå tekniska universitet, 2013
National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-22091 (URN)17a3712c-823a-4582-b0b0-b2172aa169f6 (Local ID)17a3712c-823a-4582-b0b0-b2172aa169f6 (Archive number)17a3712c-823a-4582-b0b0-b2172aa169f6 (OAI)
Note

För godkännande; 2013; 20130419 (shashi)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Zhang, P., Yi, C., Nordlund, E., Shirzadegan, S., Nyberg, U., Malmgren, L. & Nordqvist, A. (2013). Numerical back-analysis of simulated rockburst field tests by using coupled numerical technique (ed.). In: (Ed.), Yves Potvin; B.G.H. Brady (Ed.), Ground Support 2013: Proceedings of the Seventh International Symposium on Ground Support in Mining and Underground Construction. Paper presented at International Symposium on Ground Support in Mining and Underground Construction : 13/05/2013 - 15/05/2013 (pp. 565-581). Perth, Australia: Australian Center for Geomechanics
Open this publication in new window or tab >>Numerical back-analysis of simulated rockburst field tests by using coupled numerical technique
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2013 (English)In: Ground Support 2013: Proceedings of the Seventh International Symposium on Ground Support in Mining and Underground Construction / [ed] Yves Potvin; B.G.H. Brady, Perth, Australia: Australian Center for Geomechanics , 2013, p. 565-581Conference paper, Published paper (Refereed)
Abstract [en]

In order to assess the capacity of ground support systems when submitted to dynamic loading, simulated rockburst tests utilizing blasting have been performed for many years in different countries with limited success. In general, the blasts need to be carefully designed in order to reach the goal; however, different blast layouts (e.g. blasthole angle, burden) have been used based on researcher’s experience without conducting detailed analyses, the exception being a field test by CSIR. Recently, field trials have been conducted at the LKAB Kiirunavaara underground mine with some unexpected results which show that either the whole tested panel was destroyed or only a few fractures were formed without any ejections being observed. The aim of this paper is to investigate the failure mechanism in the simulated rockburst tests and improve the blast design by back-analyzing the test results using a coupled numerical modeling technique. The blast was simulated by using finite element method (LS-DYNA) and the dynamic interaction between the blasting generated waves and the opening was simulated by using discrete element modeling (UDEC) with the dynamic input from LS-DYNA. The numerical modeling showed that blasting can create both radial fractures radiating from the blasthole and fractures parallel or sub-parallel to the surface of the tested panel caused by reflected tensile stress waves. By comparing the results of the numerical modeling with the measured data, it is shown that the collapse failure was mainly controlled by the creation of a cone-shaped area formed by radial fractures and the burden seems to be a critical factor. In order to obtain fractures caused by reflected tensile stress waves and reduce blasting induced radial fractures, 2 parallel blastholes are suggested with larger burden (> 5 m) for future tests. Furthermore, the limitation of the current numerical modeling has also been discussed. The coupled numerical technique has shown its advantage when simulating blasting as well as interaction between waves and opening and it can thus be used as a tool for extrapolating results from simulated rockburst experiments if detailed geological structure and ground support system can be incorporated in the model and the model can be well calibrated.

Place, publisher, year, edition, pages
Perth, Australia: Australian Center for Geomechanics, 2013
National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-27851 (URN)16ae608b-d079-4170-b5ca-88ee9758c9eb (Local ID)978-0-9806154-7-0 (ISBN)16ae608b-d079-4170-b5ca-88ee9758c9eb (Archive number)16ae608b-d079-4170-b5ca-88ee9758c9eb (OAI)
Conference
International Symposium on Ground Support in Mining and Underground Construction : 13/05/2013 - 15/05/2013
Note
Godkänd; 2013; 20131129 (pinzha)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-04-17Bibliographically approved
Edelbro, C., Sjöberg, J., Dahner-Lindqvist, C. & Malmgren, L. (2012). Prediction and follow-up of failure and fallouts in footwall drifts in the Kiirunavaara mine (ed.). Canadian geotechnical journal (Print), 49(5), 546-559
Open this publication in new window or tab >>Prediction and follow-up of failure and fallouts in footwall drifts in the Kiirunavaara mine
2012 (English)In: Canadian geotechnical journal (Print), ISSN 0008-3674, E-ISSN 1208-6010, Vol. 49, no 5, p. 546-559Article in journal (Refereed) Published
Abstract [en]

A likely result of changes in rock stresses due to progressing mining is an increased number of compressive stress–induced failures. This paper presents the results from numerical analysis and observations of stress-induced fallouts infootwall drifts in the Kiirunavaara underground mine. A brittle-plastic cohesion-softening friction-hardening (CSFH) material model was used for simulating brittle fallouts. To account for mining-induced stress changes, the local model stress boundary conditions were extracted from a global model. The rock mass properties were based on field observations in the footwall drifts as well as on results from laboratory testing. A multi-stage analysis was carried out to gradually change the stresses to simulate mining progress. A parametric study was conducted in which strength properties, location, and shape of the footwall drift were varied. Yielded elements and maximum shear strain were used as damage and fallout indicators. The modelling results were sensitive to the shape of the drift. The location of the predicted fallouts was in good agreement with the location of observed fallouts for the case in which the drift roof was simulated flatter than the theoretical cross section. The results indicate that the true shape of the drift is different from the planned one

Keywords
Civil engineering and architecture - Geoengineering and mining engineering, Bergmekanik, Mining, Samhällsbyggnadsteknik och arkitektur - Geoteknik och gruvteknik
National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-4638 (URN)10.1139/t2012-012 (DOI)000303505000004 ()2-s2.0-84860465685 (Scopus ID)29ca456b-92b2-48a6-85b0-741a42347aae (Local ID)29ca456b-92b2-48a6-85b0-741a42347aae (Archive number)29ca456b-92b2-48a6-85b0-741a42347aae (OAI)
Note

Validerad; 2012; 20120412 (carik)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Shirzadegan, S., Nordlund, E., Nyberg, U., Zhang, P. & Malmgren, L. (2011). Rock support subjected to dynamic loading: Field testing of ground support using simulated rockburst (ed.). In: (Ed.), Qihu Qian; Yingxin Zhou (Ed.), Harmonising rock engineering and the environment: proceedings of the 12th ISRM International Congress on Rock Mechanics, Beijing, October 18 - 21, 2011. Paper presented at ISRM International Congress on Rock Mechanics : 18/10/2011 - 21/10/2011 (pp. 1269-1273). Leiden: CRC Press/Balkema
Open this publication in new window or tab >>Rock support subjected to dynamic loading: Field testing of ground support using simulated rockburst
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2011 (English)In: Harmonising rock engineering and the environment: proceedings of the 12th ISRM International Congress on Rock Mechanics, Beijing, October 18 - 21, 2011 / [ed] Qihu Qian; Yingxin Zhou, Leiden: CRC Press/Balkema , 2011, p. 1269-1273Conference paper, Published paper (Refereed)
Abstract [en]

Increasing the mining depth at LKABs Kiirunavaara mine located in the northern part of Sweden is leading to higher stress magnitudes, resulting in increased seismic activity and more rockburst damage. The effectiveness of various ground support systems under dynamic loading conditions has therefore become of prime interest to LKAB for successful and safe mining at deep levels. Therefore, a series of rockburst simulations will be conducted, using explosives to generate the dynamic load, on a number of support systems. This paper covers the results from the first trial test called Zero test-1. The test included ground motion measurements with a number of accelerometers, fracture investigation, ground and support motion imaging, as well as the deformation measurements. The methodology used to simulate rockbursts is discussed and the issues met in these tests are also addressed for further improvement.

Place, publisher, year, edition, pages
Leiden: CRC Press/Balkema, 2011
National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-37173 (URN)b1b57ebf-43b9-449e-9034-0d764168ebaa (Local ID)978-0-415-80444-8 (ISBN)b1b57ebf-43b9-449e-9034-0d764168ebaa (Archive number)b1b57ebf-43b9-449e-9034-0d764168ebaa (OAI)
Conference
ISRM International Congress on Rock Mechanics : 18/10/2011 - 21/10/2011
Note
Godkänd; 2012; 20120229 (andbra)Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2017-11-25Bibliographically approved
Nordlund, E., Saiang, D., Zhang, P., Basarir, H., Nyberg, U., Shirzaegan, S., . . . Sandström, D. (2011). Rock support system in interaction with the rock (ed.). Paper presented at Bergforsk Annual Meeting 2011 : 04/05/2011 - 05/05/2011. Paper presented at Bergforsk Annual Meeting 2011 : 04/05/2011 - 05/05/2011.
Open this publication in new window or tab >>Rock support system in interaction with the rock
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2011 (English)Conference paper, Oral presentation only (Other academic)
National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-32949 (URN)79f14128-8867-45ad-8c2e-5eb59fcd7746 (Local ID)79f14128-8867-45ad-8c2e-5eb59fcd7746 (Archive number)79f14128-8867-45ad-8c2e-5eb59fcd7746 (OAI)
Conference
Bergforsk Annual Meeting 2011 : 04/05/2011 - 05/05/2011
Note
Godkänd; 2011; 20110816 (ysko)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-06-11Bibliographically approved
Nordlund, E., Nyberg, U., Saiang, D., Shirzadegan, S., Westblom, M., Zhang, P., . . . Malmgren, L. (2011). Samverkan mellan bergförstärkningssystem och bergmassa (ed.). In: (Ed.), (Ed.), Bergmekanikdag 2011: Föredrag. Paper presented at Bergmekanikdag 2011 : 14/03/2011 - 14/03/2011 (pp. 19-28). : Stiftelsen bergteknisk forskning - Befo
Open this publication in new window or tab >>Samverkan mellan bergförstärkningssystem och bergmassa
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2011 (Swedish)In: Bergmekanikdag 2011: Föredrag, Stiftelsen bergteknisk forskning - Befo , 2011, p. 19-28Conference paper, Published paper (Other academic)
Place, publisher, year, edition, pages
Stiftelsen bergteknisk forskning - Befo, 2011
Series
Bergmekanikdag Stockholm, ISSN 0281-4714
National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-32348 (URN)6d441bef-5de8-4a8f-8828-38dabab02668 (Local ID)6d441bef-5de8-4a8f-8828-38dabab02668 (Archive number)6d441bef-5de8-4a8f-8828-38dabab02668 (OAI)
Conference
Bergmekanikdag 2011 : 14/03/2011 - 14/03/2011
Note
Godkänd; 2011; 20110825 (ysko)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-04-16Bibliographically approved
Malmgren, L. & Nordlund, E. (2008). Interaction of shotcrete with rock and rock bolts: a numerical study (ed.). Paper presented at . International Journal of Rock Mechanics And Mining Sciences, 45(4), 538-553
Open this publication in new window or tab >>Interaction of shotcrete with rock and rock bolts: a numerical study
2008 (English)In: International Journal of Rock Mechanics And Mining Sciences, ISSN 1365-1609, E-ISSN 1873-4545, Vol. 45, no 4, p. 538-553Article in journal (Refereed) Published
Abstract [en]

The shotcrete-rock interaction is very complex and is influenced by a number of factors. The influence of the following factors was investigated by a series of numerical analyses: the surface roughness of the opening, the rock strength and Young's modulus, the discontinuities, the extent and properties of the excavated disturbed zone, the mechanical properties of the interface between shotcrete and rock, and the thickness of the shotcrete lining and the rock bolts. The study was carried out as a sensitivity analysis. The results showed that the rock strength and the surface roughness had significant impact on the number of failures at the rock-shotcrete interface and in the shotcrete lining. Furthermore, the behaviour of the lining is sensitive to small amplitudes of the surface roughness. In all the cases investigated, a high interface strength was favourable. The results indicate that if a thick shotcrete lining is dependent on the bond strength. The benefit of using a thicker lining can be doubtful. The analyses showed that for an uneven surface the extent of the EDZ had a minor effect on the behaviour of the shotcrete lining. Furthermore, if rock bolts were installed at the apex of the protrusion instead of at the depression, the number of failures decreased both at the interface and in the lining

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-8753 (URN)10.1016/j.ijrmms.2007.07.024 (DOI)000255622100007 ()2-s2.0-40649084102 (Scopus ID)74983bb0-7373-11dd-a60f-000ea68e967b (Local ID)74983bb0-7373-11dd-a60f-000ea68e967b (Archive number)74983bb0-7373-11dd-a60f-000ea68e967b (OAI)
Note
Validerad; 2008; 20080826 (ysko)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved

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