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Compaction- and strength properties of stabilised and unstabilised fine-grained tills

Lindh, Per LU (2004)
Abstract
Fine-grained soils are often regarded as problematic soils in earthworks because of their water- and frost sensitivity. Only limited amounts of fine-grained tills are used as earthwork material today. The main objective of this thesis is to improve the knowledge of how to use and also treat a fine-grained till, so that a greater amount can be utilised as earthwork material. To achieve an increasing use of fine-grained tills, they must be handled in a certain way or treated/modified to achieve the desired properties. This thesis is focused on the compaction- and strength- properties of tills, both untreated and treated with a stabilising agents.



Compaction is essential to achieve a good base for foundations for roads,... (More)
Fine-grained soils are often regarded as problematic soils in earthworks because of their water- and frost sensitivity. Only limited amounts of fine-grained tills are used as earthwork material today. The main objective of this thesis is to improve the knowledge of how to use and also treat a fine-grained till, so that a greater amount can be utilised as earthwork material. To achieve an increasing use of fine-grained tills, they must be handled in a certain way or treated/modified to achieve the desired properties. This thesis is focused on the compaction- and strength- properties of tills, both untreated and treated with a stabilising agents.



Compaction is essential to achieve a good base for foundations for roads, railways and other constructions. To achieve a good result, the water content of the soil to be compacted must be within a certain range. Densification of fine-grained soils at low water contents is about to overcome the soils' “cohesion”. The soils' apparent cohesion is the sum of cohesion and matrix suction. The density increase during compaction is related to the applied compaction energy and the water content of the soils.



The results in this study are based on both laboratory investigations and well as field studies. The laboratory results are based on tests performed on 13 different soils. The main type has been clay till but coarser soils such as clayey sand tills have also been studied. The field tests have been performed at two different sites.



To conclude: the thesis work shows that fine-grained tills can be used as qualified fills in earthworks, and that the MCA (Moisture Condition Apparatus) has been proven to be a very efficient and accurate tool to predict the properties of a fine-grained till.



The relation between the undrained shear strength, cu and MCV (Moisture Condition Value) is expressed by the following equation; cu = 14.1*e^(0.22*MCV) where cu is the undrained shear strength in kPa.



Lime is the main soil-stabilising agent. However, cement may be preferred in cold weather conditions since to the chemical reactions also occur at low temperature.



Blended binders have proven to be very efficient and could well compete with single binders and in many cases give a considerably better effect than a single binder. Blended binders have many advantages regarding the binders’ working period.



The evaluations of blended binders are preferable performed with response surface methodology (RSM) a statistical evaluation technique that evaluates the interactions between the different agents. Different RSM techniques should be used depending on which type of parameter is to be evaluated. (Less)
Abstract (Swedish)
Popular Abstract in Swedish

Finkorniga moräner betraktas ofta som problemjordar inom anläggningsbranschen beroende på jordarnas känslighet för förändringar i vatteninnehåll och för deras tjälegenskaper. I dagsläget används endast en begränsad mängd finkorniga moräner i anläggningsbyggande. Huvudmålet med denna avhandling har varit att öka kunskapen om dessa jordars egenskaper och att finna/utveckla möjligheter att behandla dessa så att de kan få ökad användning i anläggningsbyggandet.



För att uppnå en ökad användning av finkorniga moräner gäller det att de behandlas på ett korrekt sätt eller att deras egenskaper förändras så att de uppfyller satta kriterier. Denna avhandling är fokuserad på jordarnas... (More)
Popular Abstract in Swedish

Finkorniga moräner betraktas ofta som problemjordar inom anläggningsbranschen beroende på jordarnas känslighet för förändringar i vatteninnehåll och för deras tjälegenskaper. I dagsläget används endast en begränsad mängd finkorniga moräner i anläggningsbyggande. Huvudmålet med denna avhandling har varit att öka kunskapen om dessa jordars egenskaper och att finna/utveckla möjligheter att behandla dessa så att de kan få ökad användning i anläggningsbyggandet.



För att uppnå en ökad användning av finkorniga moräner gäller det att de behandlas på ett korrekt sätt eller att deras egenskaper förändras så att de uppfyller satta kriterier. Denna avhandling är fokuserad på jordarnas packnings- och hållfasthetsegenskaper både med och utan bindemedel.



Resultaten i denna avhandling är till största delen baserade på laboratorieförsök. Laboratorieförsöken har omfattat 13 olika jordar varav huvuddelen är lermoräner men också jordar som leriga sandmoräner har studerats. Fältförsök har utförts på två platser.



Packning är mycket viktig för att uppnå en bra grundläggning av vägar, järnvägar och övriga konstruktioner. För att uppnå ett bra resultat måste vattenkvoten i jorden vara inom ett visst spann. Packning av en finkornig morän med låg vattenkvot handlar om att övervinna dess kohesion. Jordens skenbara kohesion är summan av porundertryck och äkta kohesion. Ökningen av jordens densitet vid packning är relaterad till använd packningsenergi och jordens vattenkvot.



Denna avhandling visar att finkorniga moräner kan användas som kvalificerat fyllningsmaterial och att MCA har visat sig vara ett mycket effektivt och exakt redskap för att prediktera finkorniga jordars egenskaper. Vidare visas att med hjälp av MCV är det möjlig att prediktera en jords packnings- och hållfasthetsegenskaper även för en modifierad jord.



Relationen mellan odränerad skjuvhållfasthet, c u , och MCV(Moisture Condition Value) kan uttryckas enligt ekvation cu =14,1*e^(0,22*MCV) där cu är uttryckt i kPa.



En finkornig morän kan läggas upp för avvattning genom luftning men en mycket snabbare och mer precis behandling är modifiering som dessutom är mindre väderberoende. Försöken visar att finkorniga svenska moräner kan behandlas med både enkla och blandade bindemedel. Kalk är det dominerande bindemedlet men cement kan i vissa sammanhang vara att föredra eftersom cement reagerar även vid låga temperaturer.



Blandade bindemedel har visat sig väl så bra som enkla bindemedel och kan i många fall ge bättre resultat. Blandade bindemedel har oftast längre bearbetbar tid och är därför att föredra.



Vid utvärdering av blandade bindemedels effekt bör responsytemodellen användas. Detta är en statistisk utvärderingsmetod som kan visa på om där föreligger samspelseffekter mellan olika bindemedel. Beroende på vilka parametrar som skall utvärderas kan olika responsytemodeller användas (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Rogers, Christopher, Professor, University of Birmingham, UK
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Väg- och vattenbyggnadsteknik, Compaction, Fine-grained tills, Strength, Civil engineering, Soil stabilisation/modification, hydraulic engineering, soil mechanics, offshore technology, Material technology, Materiallära, materialteknik
pages
368 pages
publisher
Soil Mechanics and Foundation Engineering
defense location
V-building, room V:A, John Ericssons väg 1, Lund Institute of Technology.
defense date
2004-06-03 10:15:00
ISBN
91-973723-5-8
language
English
LU publication?
yes
id
a8392800-2cc7-4e6a-8f84-969a764ad2c3 (old id 21787)
date added to LUP
2016-04-04 10:49:48
date last changed
2018-11-21 21:01:01
@phdthesis{a8392800-2cc7-4e6a-8f84-969a764ad2c3,
  abstract     = {{Fine-grained soils are often regarded as problematic soils in earthworks because of their water- and frost sensitivity. Only limited amounts of fine-grained tills are used as earthwork material today. The main objective of this thesis is to improve the knowledge of how to use and also treat a fine-grained till, so that a greater amount can be utilised as earthwork material. To achieve an increasing use of fine-grained tills, they must be handled in a certain way or treated/modified to achieve the desired properties. This thesis is focused on the compaction- and strength- properties of tills, both untreated and treated with a stabilising agents.<br/><br>
<br/><br>
Compaction is essential to achieve a good base for foundations for roads, railways and other constructions. To achieve a good result, the water content of the soil to be compacted must be within a certain range. Densification of fine-grained soils at low water contents is about to overcome the soils' “cohesion”. The soils' apparent cohesion is the sum of cohesion and matrix suction. The density increase during compaction is related to the applied compaction energy and the water content of the soils.<br/><br>
<br/><br>
The results in this study are based on both laboratory investigations and well as field studies. The laboratory results are based on tests performed on 13 different soils. The main type has been clay till but coarser soils such as clayey sand tills have also been studied. The field tests have been performed at two different sites.<br/><br>
<br/><br>
To conclude: the thesis work shows that fine-grained tills can be used as qualified fills in earthworks, and that the MCA (Moisture Condition Apparatus) has been proven to be a very efficient and accurate tool to predict the properties of a fine-grained till.<br/><br>
<br/><br>
The relation between the undrained shear strength, cu and MCV (Moisture Condition Value) is expressed by the following equation; cu = 14.1*e^(0.22*MCV) where cu is the undrained shear strength in kPa.<br/><br>
<br/><br>
Lime is the main soil-stabilising agent. However, cement may be preferred in cold weather conditions since to the chemical reactions also occur at low temperature.<br/><br>
<br/><br>
Blended binders have proven to be very efficient and could well compete with single binders and in many cases give a considerably better effect than a single binder. Blended binders have many advantages regarding the binders’ working period.<br/><br>
<br/><br>
The evaluations of blended binders are preferable performed with response surface methodology (RSM) a statistical evaluation technique that evaluates the interactions between the different agents. Different RSM techniques should be used depending on which type of parameter is to be evaluated.}},
  author       = {{Lindh, Per}},
  isbn         = {{91-973723-5-8}},
  keywords     = {{Väg- och vattenbyggnadsteknik; Compaction; Fine-grained tills; Strength; Civil engineering; Soil stabilisation/modification; hydraulic engineering; soil mechanics; offshore technology; Material technology; Materiallära; materialteknik}},
  language     = {{eng}},
  publisher    = {{Soil Mechanics and Foundation Engineering}},
  school       = {{Lund University}},
  title        = {{Compaction- and strength properties of stabilised and unstabilised fine-grained tills}},
  year         = {{2004}},
}