1151
Hydro-mechanical properties of lime-treated London Clay
Propriétés hydromécaniques de l’argile de Londres traitée à la chaux
Mavroulidou M., Zhang X., Kichou Z., Gunn M.J.
Faculty of Engineering Science and the Built Environment, London South Bank University, 103 Borough Road London
SE1 0AA, United Kingdom
ABSTRACT: This paper investigates the effect of lime on the hydromechanical properties of untreated London Clay (a high plasticity
clay) and lime-treated and London Clay samples, using two different curing methodologies, and two different dosages of hydrated
lime beyond the Initial Lime Consumption level. They were then subject to a number of triaxial tests, to investigate the effect of the
above factors on the properties and behaviour of the treated soil in the saturated and partially saturated state. Soil water retention
curves were also determined and the favourable effect of the lime on the volumetric stability of the soil demonstrated.
RÉSUMÉ : On étudie l’effet de la chaux sur les propriétés hydromécaniques de l’argile de Londres, à partir d’une série d’essais
triaxiaux.
On décrit
l’effet du dosage en chaux, des conditions de cure et de la saturation partielle
.
Les résultats expérimentaux
indiquent que la chaux a réduit la compressibilité et a amélioré la résistance de cisaillement du sol. Cependant les éprouvettes traitées
à la chaux ont affiché un comportement avec radoucissement en grandes déformations, contrairement aux éprouvettes d’argile de
Londres qui ont affiché un comportement avec écrouissage positif (durcissement). Ce comportement était particulièrement prononcé
dans le cas des éprouvettes à dosage en chaux élevé. Dans la suite on mesure la succion et les courbes de retention d’eau à l’aide de la
méthode du papier filtre, démontrant l’effet favorable de la chaux sur la stabilité volumique du sol.
KEYWORDS: lime treated London Clay; hydro-mechanical properties; triaxial testing; soil water retention curve
1 INTRODUCTION
Lime treatment has been extensively used to improve the
engineering properties of clay soils; namely to increase the
workability of high plasticity soils during construction, and for
the stabilisation of roads and pavements (capping layers, sub-
bases and subgrades). With these applications in mind, research
on lime-stabilised clays has historically focused mainly on
properties such as plasticity, CBR or Unconfined Compression
Strength (UCS). There is however limited information in the
international literature based on triaxial testing that can be used
to describe the constitutive behaviour of lime-treated soils.
There is also lack of information on the properties of these soils
in the partially saturated state, although they are typically
compacted and hence, partially saturated. This paper
investigates the mechanical properties of a high- plasticity clay
(London Clay) and the effect of factors such as lime percentage
and curing methodology through CD triaxial tests. Results for
the soil water retention curve of this soil are also presented.
2 MATERIALS AND EXPERIMENTAL PROCEDURES
2.1 Materials
The soil used in this study was London Clay taken from an
excavation at Westminster Bridge in the city of London and
depths corresponding to B2 stratigraphic unit (King, 1981). The
soil was air-dried at an average temperature of 22
0
C and a
relative humidity of 60% for a month and pulverised. Figure 1
shows the particle size distribution of the portion of the soil
passing the BS 425 μm sieve. X-ray diffraction (XRD) tests
showed 50% Illite, 26% Montomorillonite, 15% Kaolinite and
9% Chlorite (relative % of each clay mineral with respect to
clay fraction).
Figure 1. Particle size distribution of the London Clay soil
Figure 2. Plasticity characteristics for different percentages of lime
