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An Experimental Study to Measure Grout Penetrability, Improve the Grout Spread, and Evaluate the Real Time Grouting Control Theory
KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.ORCID iD: 0000-0002-5394-3868
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Due to the significant influence of the grout penetrability properties on spread of grout in rock fractures, this study aimed to investigate the grout penetrability from four different aspects. In Part (a), after review of all the existing methodologies developed to measure the grout penetrability, Filter-pump and Penetrability-meter were examined against Short-slot to figure out which one is more reliable. The study decisively considered Short-slot more reliable. In part (b), the so-called varying aperture long slot (VALS), an artificial fracture with apertures of 230-10 μm, was developed to study the gout penetrability more realistically. In part (c), a low-frequency rectangular pressure impulse was introduced to improve the grout spread by successive erosion of the produced filter cakes in consecutive cycles. The results showed considerable improvement in experiments using Short-slot. The dissipation of the pressure impulses was then investigated using VALS with noticeable remaining amplitudes after 2.0-2.7 m. In part (d), VALS was once more introduced to examine RTGC theory in a fracture with variable aperture. The study showed a relatively satisfactory agreement between the experimental results and the predictions of the grout propagation using the hydraulic aperture, whereas the predictions using the mean physical aperture showed considerably faster spread.

Abstract [sv]

För att uppnå den täthet som krävs i undermarkskonstruktioner är det nödvändigt att uppnå tillräcklig spridning av bruket vid injekteringen. Cementbaserade injekteringsmedel är vanligast inom injekteringsindustrin, eftersom det har flera fördelar, särskilt från ekonomisk och miljömässig synvinkel. Eftersom inträngningsförmågan kan påverkas betydligt hos injekteringsmedel beroende på vilket bruk man använder, är syftet med denna avhandling att studera: a) Vilka av de befintliga metoder som har utvecklats för att mäta inträngningsförmågan hos injekteringsmedel är tillförlitliga? b) Hur kan man mäta inträngningsförmågan hos injekteringsmedel mer realistiskt? c) Hur kan man förbättra spridningen hos injekteringsmedel med hjälp av dynamiska tryckimpulser? och d) Kan Real Time Grouting Control (RTGC)-teorin användas för att förutse spridningen hos injekteringsmedel i en artificiell spricka med varierande vidd?

I del a) av studien genomfördes en undersökning av alla befintliga metoder som har utvecklats för att mäta inträngningsförmågan hos injekteringsmedel. Därefter genomfördes en jämförelse mellan Filterpumpen, Filterpressen (d.v.s. två av de vanligaste metoderna i svensk injekteringsindustri) och metoden Kort spalt under så lika provförhållanden som möjligt. Studien visade att Kort spalt är tillförlitligare på grund av dess mer realistiska provförhållanden (d.v.s. geometrin, trycket och injekteringsvolymen) och är därmed en bättre utvärderingsmetod.

I del b) utvecklades en så kallad Varying Aperture Long Slot (VALS), en fyra meter lång artificiell spricka med minskande spaltvidder (från 230 till 10 μm), som är en mer realistisk metod för att studera inträngningsförmågan hos injekteringsmedel under statiska/dynamiska tryckförhållanden upp till 20 bar.

I del c) användes en lågfrekvent rektangulär tryckimpuls för att förbättra spridningen hos injekteringsmedlet genom successiv erosion av filterkakor som har byggts vid förträngningar i konsekutiva cykler. Resultaten visade en förbättring på upp till 11 gånger mer volym i mätningar med Kort spalt med 30-43 μm breda spaltvidder. Sedan, spridningen av tryckimpulserna undersöktes längs VALS. Resultaten visade att de återstående amplituderna av tryckimpulser kan vara så stora som 46% respektive 25% av den applicerade amplituden 2,0 m respektive 2,7 m in i sprickan.

I del d) användes VALS igen för att undersöka om RTGC-teorin kan användas för att bedöma spridningen av injekteringsmedel i en konstgjord spricka med variabel spaltvidd. Studien visade en förhållandevis tillfredsställande överensstämmelse mellan försöksresultaten och förutsägelserna av spridningen hos injekteringsmedel när man tog hänsyn till den hydrauliska öppningen. Som jämföreslse gav förutsägelserna baserade på den genomsnittliga fysiska öppningen (felaktigt) en betydligt snabbare spridning. Detta visar att användning av den genomsnittliga fysiska öppningen inte alltid är lämpligt vid tillämpning av RTGC-teori. Beroende på de geometriska förhållandena kan den hydrauliska öppningen ge en mer realistisk förutsägelse av spridningen hos injekteringsmedlet.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2017. , p. 62
Series
TRITA-JOB PHD, ISSN 1650-9501 ; 1027
National Category
Geotechnical Engineering
Research subject
Civil and Architectural Engineering
Identifiers
URN: urn:nbn:se:kth:diva-217906ISBN: 978-91-7729-611-9 (print)OAI: oai:DiVA.org:kth-217906DiVA, id: diva2:1158297
Public defence
2018-01-09, Kollegiesalen, Brinellvägen 8, 114 28, Stockholm, 10:00 (English)
Opponent
Supervisors
Funder
Swedish Transport AdministrationSBUF - Sveriges Byggindustriers UtvecklingsfondRock Engineering Research Foundation (BeFo)
Note

QC 20171121

Available from: 2017-11-21 Created: 2017-11-19 Last updated: 2017-11-21Bibliographically approved
List of papers
1. Uncertainties in Grout Penetrability Measurements; Evaluation and Comparison of Filter pump, Penetrability meter and Short slot
Open this publication in new window or tab >>Uncertainties in Grout Penetrability Measurements; Evaluation and Comparison of Filter pump, Penetrability meter and Short slot
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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
Keyword
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
2. Varying aperture long slot (VALS), a method for studying grout penetrability into fractured hard rock
Open this publication in new window or tab >>Varying aperture long slot (VALS), a method for studying grout penetrability into fractured hard rock
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2017 (English)In: ASTM geotechnical testing journal, ISSN 0149-6115, E-ISSN 1945-7545, Vol. 40, no 5, p. 871-882Article in journal (Refereed) Published
Abstract [en]

This paper presents the design, manufacturing, and assembly of a new laboratory apparatus for investigation of grout filtration tendency and penetrability into rock fractures. The method makes it possible to examine grout samples composed of a wide range of cements and additives/ admixtures with different water-to-solid ratios. The apparatus can be used to investigate the influence of different parameters on grout penetrability. Examples of these parameters include the cement particle size/distribution curves/chemical compositions, and the type and ratio of additives/admixtures that provide a variety of setting/hardening times, and rheological and strength properties. The grouting operation into the rock fractures is replicated using an artificial slot with 4-m-long constrictions varying from 230 to 10 μm, and selective inlet and outlet. The apparatus can also accommodate grouting experiments under both static and dynamic pressure conditions up to 1, 500 kPa to study their influence. Illustrative results are also provided.

Place, publisher, year, edition, pages
ASTM International, 2017
Keyword
Cement-grout, Filtration tendency, Grout penetrability, Varying aperture long slot
National Category
Geotechnical Engineering
Research subject
Civil and Architectural Engineering
Identifiers
urn:nbn:se:kth:diva-216352 (URN)10.1520/GTJ20160179 (DOI)000413285400012 ()2-s2.0-85029087586 (Scopus ID)
Funder
Swedish Transport AdministrationSBUF - Sveriges Byggindustriers UtvecklingsfondRock Engineering Research Foundation (BeFo)
Note

QC 20171023

Available from: 2017-10-23 Created: 2017-10-23 Last updated: 2018-02-27Bibliographically approved
3. An Experimental Approach to the Development of Dynamic Pressure to Improve Grout Spread
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
Keyword
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
4. Application of Low-Frequency Rectangular Pressure Impulse in Rock Grouting
Open this publication in new window or tab >>Application of Low-Frequency Rectangular Pressure Impulse in Rock Grouting
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2017 (English)In: Grouting 2017: Grouting, Drilling, and Verification / [ed] Byle, MJ Johnsen, LF Bruce, DA ElMohtar, CS Gazzarrini, P Richards, TD, American Society of Civil Engineers (ASCE), 2017, Vol. 2, no 288, p. 104-113Conference paper, Published paper (Refereed)
Abstract [en]

In order to sufficiently seal an underground facility in fractured rock, it is essential to obtain adequate grout spread into the surrounding fractures. The grout spread itself depends on parameters, the most significant of which are the filtration tendency and rheological properties. These properties can be affected by the applied pressure. High-frequency oscillating pressure has been shown to improve grout spread by virtue of reducing the grout viscosity. However, this method has not yet been industrialized due to the quick dissipation of the oscillation along a fracture. In a recent investigation, we examined a low-frequency rectangular pressure-impulse using a short slot. The results showed significant improvements in the injected grout volume in comparison to the static pressure results. In this paper, we examine the method in a considerably longer artificial fracture in order to investigate the dissipation of the pressure impulses. The study indicates the potential of the method to improve the grout spread in rock grouting.

Place, publisher, year, edition, pages
American Society of Civil Engineers (ASCE), 2017
Series
Geotechnical Special Publication, ISSN 0895-0563 ; 288
Keyword
Grout spread, Filtration, Erosion, Cement-grout, Dynamic grouting, Rectangular pressure impulse, VALS
National Category
Geotechnical Engineering
Research subject
Civil and Architectural Engineering
Identifiers
urn:nbn:se:kth:diva-212961 (URN)10.1061/9780784480793.010 (DOI)000406688400010 ()2-s2.0-85025457576 (Scopus ID)978-0-7844-8079-3 (ISBN)
Conference
5th International Conference on Grouting, Deep Mixing, and Diaphragm Walls, Grouting 2017, Honolulu, United States, 9 July 2017 through 12 July 2017
Funder
Swedish Transport AdministrationRock Engineering Research Foundation (BeFo)SBUF - Sveriges Byggindustriers Utvecklingsfond
Note

QC 20170828

Available from: 2017-08-28 Created: 2017-08-28 Last updated: 2018-02-28Bibliographically approved
5. Evaluation of the Real Time Grouting Control (RTGC) Theory using an Artificial Fracture with Variable Aperture
Open this publication in new window or tab >>Evaluation of the Real Time Grouting Control (RTGC) Theory using an Artificial Fracture with Variable Aperture
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2018 (English)Manuscript (preprint) (Other academic)
Abstract [en]

The real time grouting control (RTGC) theory has been developed to monitor the spread of grout in rock fractures. It predicts the extent of the grout spread over time using the grout properties and the applied pressure. Despite extensive work conducted to verify it in both the lab and the field, it has not yet been sufficiently investigated in the lab under geometry conditions similar to a real fracture in rock. This paper presents a novel effort to examine the performance of the RTGC theory in the presence of constrictions by using an artificial fracture, the so-called varying aperture long slot (VALS). The paper compares the predictions of grout propagation with the experimental results. The predictions obtained using a hydraulic aperture, the way that the theory was previously used in the early stages of development, showed relatively good agreement with the experimental results. In predictions obtained using the mean-physical aperture, the way that the theory is currently used in field applications, the results showed considerably faster spread than the experimental results. This suggests that use of the mean-physical aperture does not always give a good approximation of the apertures to employ in predictions using the RTGC theory. Depending on the geometry conditions, the hydraulic aperture might be more realistic.

Keyword
Penetrability, Filtration, Real time grouting control (RTGC) theory, Varying aperture long slot (VALS), Cement-based grout, Hydraulic aperture, Mean-physical aperture
National Category
Geotechnical Engineering
Research subject
Civil and Architectural Engineering
Identifiers
urn:nbn:se:kth:diva-217905 (URN)
Funder
Rock Engineering Research Foundation (BeFo)SBUF - Sveriges Byggindustriers UtvecklingsfondSwedish Transport Administration
Note

QC 20171121

Available from: 2017-11-19 Created: 2017-11-19 Last updated: 2017-11-21Bibliographically approved

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