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Publications (10 of 92) Show all publications
Wonglert, A., Jongpradist, P., Jamsawang, P. & Larsson, S. (2018). Bearing capacity and failure behaviors of floating stiffened deep cement mixing columns under axial load. Soil and foundation, 58(2), 446-461
Open this publication in new window or tab >>Bearing capacity and failure behaviors of floating stiffened deep cement mixing columns under axial load
2018 (English)In: Soil and foundation, ISSN 0038-0806, Vol. 58, no 2, p. 446-461Article in journal (Refereed) Published
Abstract [en]

This research aims to clarify and gain an insight into the impact of the length of the stiffened core and the strength of the deep cement mixing (DCM) socket on the behaviors of floating stiffened deep cement mixing (SDCM) columns. The observed behaviors include the axial ultimate bearing capacity, settlement and failure mode. The study begins by conducting a series of physical model tests as a preliminary investigation. The results reveal that the strength of the DCM socket can be reduced to a certain value by inserting a sufficiently long reinforced core to achieve the highest possible load-carrying capacity, indicating an optimum length of the stiffened core for a specific DCM socket strength. For a parametric study on the actual scale condition, full-scale load tests on a floating DCM and an SDCM column with eucalyptus wood as a core in the thick soft clay layer area were carried out to provide a reference case. The extended numerical analysis results suggest that the modes of failure depend on the length of the stiffened core and the strength of the DCM socket. The results from the numerical parametric study were used to establish a guideline chart for suggesting the appropriate length of the core in accordance with the strength of the DCM socket of the floating SDCM columns. The field pile load test results also confirm that core materials with a lower strength and stiffness, such as eucalyptus wood, could potentially be used as a reinforced core.

Place, publisher, year, edition, pages
Japanese Geotechnical Society, 2018
Keywords
DCM, SDCM, Bearing capacity, Failure, Numerical analysis, Physical model
National Category
Geosciences, Multidisciplinary
Identifiers
urn:nbn:se:kth:diva-230549 (URN)10.1016/j.sandf.2018.02.012 (DOI)000432690700015 ()2-s2.0-85042184222 (Scopus ID)
Note

QC 20180620

Available from: 2018-06-20 Created: 2018-06-20 Last updated: 2018-06-20Bibliographically approved
Wersäll, C., Nordfelt, I. & Larsson, S. (2018). Resonant roller compaction of gravel in full-scale tests. Transportation Geotechnics, 14, 93-97
Open this publication in new window or tab >>Resonant roller compaction of gravel in full-scale tests
2018 (English)In: Transportation Geotechnics, ISSN 2214-3912, Vol. 14, p. 93-97Article in journal (Refereed) Published
Abstract [en]

Results from a recent study indicated that compaction by vibratory roller can be made more time- and energy-efficient by operating at a vibration frequency close to resonance. In this paper, the results are verified and the reduction in operating time is quantified by conducting detailed full-scale tests under realistic conditions at two frequencies: the standard operating frequency of the roller and a lower frequency slightly above resonance. Compaction was done in two tests per frequency with 16 passes in each test. The obtained compaction was quantified using a combination of measurement techniques, including laser levelling, nuclear density gauge and static plate load tests. The results confirm that the lower frequency is more efficient for compaction and that utilizing resonance in the roller-soil system can reduce the number of passes. In addition, lowering the frequency reduces energy consumption, environmental impact and machine wear. 

Place, publisher, year, edition, pages
Elsevier Ltd, 2018
Keywords
Compaction, Frequency, Nuclear density gauge, Plate load test, Resonance, gravel, loading test, rock mechanics, vibration, wear
National Category
Civil Engineering
Identifiers
urn:nbn:se:kth:diva-223120 (URN)10.1016/j.trgeo.2017.11.004 (DOI)000427928700010 ()2-s2.0-85034743044 (Scopus ID)
Funder
Swedish Transport Administration
Note

Export Date: 13 February 2018; Article; Correspondence Address: Wersäll, C.; Department of Civil and Architectural Engineering, KTH Royal Institute of TechnologySweden; email: carl.wersall@byv.kth.se. QC 20180327

Available from: 2018-03-27 Created: 2018-03-27 Last updated: 2018-04-11Bibliographically approved
Prästings, A., Larsson, S. & Müller, R. (2017). Optimizing geotechnical site-investigations. In: Proceedings of the 19th International Conference on Soil Mechanics and Geotechnical Engineering, Seoul 2017: . Paper presented at 19th International Conference on Soil Mechanics and Geotechnical Engineering, 17 to 21 September 2017, Seoul 2017 (pp. 639-642).
Open this publication in new window or tab >>Optimizing geotechnical site-investigations
2017 (English)In: Proceedings of the 19th International Conference on Soil Mechanics and Geotechnical Engineering, Seoul 2017, 2017, p. 639-642Conference paper, Published paper (Refereed)
Abstract [en]

One major question to deal with in the process of updating the current version of Eurocode 7 is how to convert thequality of a performed site-investigation into a measurable context. This should, in turn, affect the safety factor applied to the soil-strength properties in a limit state. This paper presents a study in which the total uncertainty from the evaluation of undrained shearstrength in clay is assessed from single and multiple site-investigation methods with regard to both random and systematicuncertainties. A Bayesian procedure is used to convert potential reduction of random and systematic uncertainties into a measurablecontext in relation to: (1) the type of site-investigation method, (2) the combination of methods, and (3) the number of measurementsperformed.

Abstract [fr]

L’une des questions majeures qui se posent lors du processus de mise à jour de la version actuelle de l’Eurocode 7est la suivante : comment convertir la qualité d’une investigation de site en une quantité mesurable ? Cela devrait alors affecterle niveau de sécurité appliqué aux propriétés de résistance du sol dans un état limite. Cet article présente une étude au cours de laquelle l’incertitude totale découlant de l’évaluation de la résistance au cisaillement de l’argile non évacuée est évaluée à partir de méthodes d’investigation de site uniques et multiples en relation avec des incertitudes aléatoires et systématiques. Une procédure bayésienne est utilisée pour convertir la réduction potentielle des incertitudes aléatoires et systématiques en une incertitude mesurable en rapport avec : (1) le type de méthode d’investigation de site, (2) la combinaison des méthodes, (3) le nombre de mesures effectuées.

National Category
Geotechnical Engineering
Identifiers
urn:nbn:se:kth:diva-221082 (URN)2-s2.0-85040043034 (Scopus ID)
Conference
19th International Conference on Soil Mechanics and Geotechnical Engineering, 17 to 21 September 2017, Seoul 2017
Funder
Swedish Research Council Formas
Note

QC 20180115

Available from: 2018-01-12 Created: 2018-01-12 Last updated: 2018-01-15Bibliographically approved
Nejad Ghafar, A., Ali Akbar, S., Al-Naddaf, M., Draganovic, A. & Larsson, S. (2017). Uncertainties in Grout Penetrability Measurements; Evaluation and Comparison of Filter pump, Penetrability meter and Short slot. Geotechnical and Geological Engineering
Open this publication in new window or tab >>Uncertainties in Grout Penetrability Measurements; Evaluation and Comparison of Filter pump, Penetrability meter and Short slot
Show others...
2017 (English)In: Geotechnical and Geological Engineering, ISSN 0960-3182, E-ISSN 1573-1529Article in journal (Refereed) Published
Abstract [en]

To measure grout penetrability in fractured hard rock, various measuring instruments have been developed over the years. Penetrability meter and Filter pump have been designed to use in both the lab and the field. Short slot has been applicable mainly in the lab due to its complexity. The fact, that these instruments have been built based on different assumptions, limitations, and test conditions, makes their results occasionally in contradict. Deficiency in design of the instruments as well as the methods of evaluating grout penetrability is additionally a basis for uncertainty in results. This study is an experimental effort to determine and thoroughly perceive the nature of the most governing uncertainties in grout penetrability measurements. The test apparatus, procedure, and method used to evaluate the grout penetrability in both Penetrability meter and Filter pump were thus modified. The aim was to control the corresponding uncertainties and make their limitations and test conditions as similar as possible with the ones in Short slot. The results suggested that to obtain a more realistic evaluation of the grout penetrability, measurement should be accomplished at both the high and the low pressures with sufficient grout volume using Short slot. Moreover, application of both Filter pump and Penetrability meter is no longer recommended due to the revealed uncertainties.

Place, publisher, year, edition, pages
Springer, 2017
Keywords
Penetrability, Filtration, Filter pump, Penetrability meter, Short slot, Cement-based grout
National Category
Geotechnical Engineering
Research subject
Civil and Architectural Engineering
Identifiers
urn:nbn:se:kth:diva-185191 (URN)10.1007/s10706-017-0351-4 (DOI)
Funder
Swedish Transport AdministrationSBUF - Sveriges Byggindustriers UtvecklingsfondRock Engineering Research Foundation (BeFo)
Note

QS 2016

Available from: 2016-04-12 Created: 2016-04-12 Last updated: 2017-11-21Bibliographically approved
Nejad Ghafar, A., Mentesidis, A., Draganovic, A. & Larsson, S. (2016). An Experimental Approach to the Development of Dynamic Pressure to Improve Grout Spread. Rock Mechanics and Rock Engineering, 49(9), 3709-3721
Open this publication in new window or tab >>An Experimental Approach to the Development of Dynamic Pressure to Improve Grout Spread
2016 (English)In: Rock Mechanics and Rock Engineering, ISSN 0723-2632, E-ISSN 1434-453X, Vol. 49, no 9, p. 3709-3721Article in journal (Refereed) Published
Abstract [en]

Dynamic grouting is one of the methods to improve grout spread in rock that have been investigated since 1985. The results were promising, but all tests were performed under noticeable simplifications related to conditions in rock fractures. This study is an experimental approach to improve the grout spread using low-frequency instantaneous variable pressure as a new alternative with better control of filtration. The method is tested through parallel plates with constrictions of 30 and 43 µm under the applied pressures with 4 s/8 s and 2 s/2 s peak/rest periods. The results reveal conclusively the effectiveness of the method and provide a basis for further development of dynamic grouting.

Place, publisher, year, edition, pages
Springer, 2016
Keywords
Grout spread, Filtration, Erosion, Cement-based Grout, Dynamic grouting, Variable pressure
National Category
Geotechnical Engineering
Research subject
Civil and Architectural Engineering
Identifiers
urn:nbn:se:kth:diva-185192 (URN)10.1007/s00603-016-1020-2 (DOI)000382673200020 ()2-s2.0-84976299566 (Scopus ID)
Funder
SBUF - Sveriges Byggindustriers UtvecklingsfondRock Engineering Research Foundation (BeFo)Swedish Transport Administration
Note

QC 20160608

Available from: 2016-04-12 Created: 2016-04-12 Last updated: 2017-11-21Bibliographically approved
Ignat, R., Baker, S., Liedberg, S. & Larsson, S. (2016). Behavior of braced excavation supported by panels of deep mixing columns. Canadian geotechnical journal (Print), 53(10), 1671-1687
Open this publication in new window or tab >>Behavior of braced excavation supported by panels of deep mixing columns
2016 (English)In: Canadian geotechnical journal (Print), ISSN 0008-3674, E-ISSN 1208-6010, Vol. 53, no 10, p. 1671-1687Article in journal (Refereed) Published
Abstract [en]

This paper describes the instrumentation, execution and performance of two full-scale tests where a braced steel sheet pile wall interacting with rows of overlapping dry deep mixing columns was excavated and then loaded to failure. The purpose of these tests was to provide knowledge of the behavior of deep mixing column rows located in passive zone and interacting with a retaining structure. Both tests were extensively instrumented on the active as well as on the passive side of the retaining structure. In both conducted tests a stability failure of the retaining structure occurred, resulting in heave at the bottom of the excavation and large settlements of the ground surface behind the sheet pile wall. For a spacing between LC-panels of 3.0 m a very brittle failure developed suddenly in the clay between the panels with small deformations prior to failure. In the second test, with a spacing of 1.5 m between LC-panels, the failure developed in the LC-panels as well as in the clay between the panels. Even if a similar failure mechanism developed, measured horizontal displacements, horizontal stresses, and pore pressure response prior to failure differed between the tests.

Place, publisher, year, edition, pages
NRC Research Press, 2016
Keywords
dry deep mixing, field test, excavation support, failure mechanism, pore pressure response
National Category
Geotechnical Engineering
Identifiers
urn:nbn:se:kth:diva-188805 (URN)10.1139/cgj-2016-0137 (DOI)2-s2.0-84989849507 (Scopus ID)
Note

QC 20160712

Available from: 2016-06-17 Created: 2016-06-17 Last updated: 2017-11-28Bibliographically approved
Lingwanda, M., Prästings, A., Larsson, S. & Nyaoro, D. L. (2016). Comparison of geotechnical uncertainties linked to different soil characterization methods. Geomechanics and Geoengineering, 1-15
Open this publication in new window or tab >>Comparison of geotechnical uncertainties linked to different soil characterization methods
2016 (English)In: Geomechanics and Geoengineering, ISSN 1748-6025, E-ISSN 1748-6033, p. 1-15Article in journal (Refereed) Epub ahead of print
Abstract [en]

One of the essential inputs in settlement prediction models is the soil modulus, which may be obtained from laboratory tests or estimated from in situ measurements. The total uncertainty in predicting the confined modulus of a sandy soil is quantified with data from side-by-side in situ testing using the standard penetration test, the static cone penetration test, the light dynamic probing and the laboratory oedometer test. To estimate transformation errors, correlations are proposed between in situ and laboratory data. The results indicate that similar magnitudes of total uncertainties are associated with the in situ methods, which are approximately twice as high as those from the direct oedometer method. The quantified uncertainties are an important input for reliability-based designs of foundations under similar soil conditions.

Place, publisher, year, edition, pages
Taylor & Francis, 2016
National Category
Geotechnical Engineering
Identifiers
urn:nbn:se:kth:diva-161340 (URN)10.1080/17486025.2016.1184761 (DOI)2-s2.0-84969753258 (Scopus ID)
Note

QC 20160608

Available from: 2015-03-11 Created: 2015-03-11 Last updated: 2017-12-04Bibliographically approved
Nejad Ghafar, A., Mentesidis, A., Draganovic, A. & Larsson, S. (2016). Ett nytt sätt att förbättra inträngnigs egenskaperna hos cementbaserat injekteringsbruk med momentant varierande tryck. Bygg & teknik (1), 17-22
Open this publication in new window or tab >>Ett nytt sätt att förbättra inträngnigs egenskaperna hos cementbaserat injekteringsbruk med momentant varierande tryck
2016 (Swedish)In: Bygg & teknik, ISSN 0281-658X, no 1, p. 17-22Article in journal (Other (popular science, discussion, etc.)) Published
Abstract [sv]

Ett mycket viktig moment i samband med undermarksbyggande är tätning av konstruktioner för att hindra vatteninflöde eller ett eventuellt läckage av lagrade material i konstruktionen. Sedan mitten på 1980-talet har man på Kungliga tekniska högskolan (KTH) forskat kring injekteringen av sprickor i berg med varierande tryck för att förbättra inträngningsförmågan av cementbaserade bruk. I tidigare studier har man huvudsakligen undersökt effekten av högfrekventa oscillerande tryck på brukets inträngningsförmåga men den uppnådda förbättringen har visat sig vara relativt begränsad. I ett doktorandprojekt på KTH har vi genomfört en experimentell studie för att undersöka påverkan av istället ett lågfrekvent tryck med en momentan tryckförändering på brukets inträngningsförmåga. Resultaten har visat på en betydande förbättring av inträngningsförmågan hos bruket jämfört med injektering med konstant tryck. Projektet har finansierats av Stiftelsen Bergteknisk Forskning (BeFo), Svenska Byggbranschens Utvecklingsfond (SBUF) och Trafikverket.

Place, publisher, year, edition, pages
Stockholm: Förlags AB Bygg & teknik, 2016
National Category
Geotechnical Engineering
Research subject
Civil and Architectural Engineering
Identifiers
urn:nbn:se:kth:diva-180703 (URN)
Funder
SBUF - Sveriges Byggindustriers UtvecklingsfondRock Engineering Research Foundation (BeFo)Swedish Transport Administration
Note

QC 20160222

Available from: 2016-01-20 Created: 2016-01-20 Last updated: 2017-11-22Bibliographically approved
Krounis, A., Johansson, F., Spross, J. & Larsson, S. (2016). Influence of cohesive strength in probabilstic sliding stability re-assessment of concrete dams. Journal of Geotechnical and Geoenvironmental Engineering, 143(2), Article ID 04016094.
Open this publication in new window or tab >>Influence of cohesive strength in probabilstic sliding stability re-assessment of concrete dams
2016 (English)In: Journal of Geotechnical and Geoenvironmental Engineering, ISSN 1090-0241, E-ISSN 1943-5606, Vol. 143, no 2, article id 04016094Article in journal (Refereed) Published
Abstract [en]

For concrete dams, cohesive strength often constitutes a significant share of the overall shear strength of partially bonded concrete-rock interfaces. However, cohesive strength is also associated with great uncertainties that may have a significant impact on the assessed stability of the analyzed structure. In this paper, the merits of including cohesion are evaluated using a probability-based approach to analyze the sliding stability of an existing concrete gravity dam. The shear strength properties of the interface are inferred from a limited number of site-specific tests and previous knowledge from similar structures using Bayesian updating. The study shows that the potential gain from cohesive strength is strongly related to the involved uncertainties and identifies the bonding percentage and basic friction angle as the most influential parameters. The importance of testing, both with regard to the specific project and for future projects, is also highlighted.

Place, publisher, year, edition, pages
American Society of Civil Engineers (ASCE), 2016
Keywords
Cohesive strength, Concrete dam, Concrete-rock interface, Partially bonded, Sliding stability
National Category
Geotechnical Engineering
Research subject
Civil and Architectural Engineering
Identifiers
urn:nbn:se:kth:diva-185143 (URN)10.1061/(ASCE)GT.1943-5606.0001583 (DOI)000394257800001 ()2-s2.0-85010665903 (Scopus ID)
Note

QC 20160411

Available from: 2016-04-11 Created: 2016-04-11 Last updated: 2017-11-30Bibliographically approved
Wersäll, C. & Larsson, S. (2016). Influence of force ratio and frequency on vibratory surface compaction. In: Phung Duc Long (Ed.), Geotechnics for Sustainable Infrastructure Development: . Paper presented at 3rd International Conference on Geotechnics for Sustainable Infrastructure Development, Hanoi, 24th-25th Nov 2016, Vietnam.
Open this publication in new window or tab >>Influence of force ratio and frequency on vibratory surface compaction
2016 (English)In: Geotechnics for Sustainable Infrastructure Development / [ed] Phung Duc Long, 2016Conference paper, Published paper (Refereed)
National Category
Geotechnical Engineering
Identifiers
urn:nbn:se:kth:diva-187311 (URN)
Conference
3rd International Conference on Geotechnics for Sustainable Infrastructure Development, Hanoi, 24th-25th Nov 2016, Vietnam
Note

QC 20160614

Available from: 2016-05-19 Created: 2016-05-19 Last updated: 2017-08-28Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-9615-4861

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