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General Report - Session II
Laboratory Testing of Geomaterials: Strength Properties and Treated Soil
Rapport général - Session II
Essais de laboratoire des géomatériaux : propriétés mécaniques et sols traités
Kim D.-S.
Korea Advanced Institute of Science and Technology (KAIST)
ABSTRACT: This report presents a brief review of 30 papers submitted for the session on Laboratory Testing of Geomaterials
Ⅱ
:
strength properties and treated soils. The paper topics were very diverse but the papers were separated into four broad categories : 1)
shear strength, 2) treated soil, 3) testing method and 4) miscellaneous. Some papers include valuable database of important strength
parameters for design and some of the tested soils include special soils. The report includes discussions related to the categories,
summarizes the papers, and highlights their major conclusions.
RÉSUMÉ : Ce rapport présente un bref résumé des 30 contributions soumises à la session Essais de laboratoire des Géomateriaux
Ⅱ
:
propriétés mécaniques et sols traités. Les sujets traités ont été variés, mais finalement les contributions écrites ont été groupées en
quatre grandes catégories: 1) résistance au cisaillement, 2) sols traités, 3) méthode d'essai et 4) sujets divers. Certains articles
comprennent des bases de données pertinentes de paramètres importants de résistance pour la conception d’ouvrages et certains sols
testés font partie des sols spéciaux. Le rapport comprend des discussions liées aux catégories, synthétise les résultats et met en
évidence leurs principales conclusions.
KEYWORDS: laboratory test, shear strength, treated soil, testing method, database
1 INTRODUCTION
The theme of this session focuses on Laboratory Testing of
Geomaterials II: strength properties and treated soils. The 30
papers submitted to this session are reviewed and summarized
in this report. To guide readers to the most relevant papers,
Table 1 is provided in the appendix that shows the paper ID and
main focus of each paper, subdivided into four broad categories:
a) shear strength, b) treated soil, c) testing method, and d)
miscellaneous. The first session of shear strength was
subdivided by three topics: 1) database of strength and stiffness
properties, 2) gas-hydrate bearing soil and mining by-products,
and 3) soil fabric and particle characteristics.
The diversity of authors and tested soils truly highlights the
international nature of our profession. Authors are from
Australia, Brazil, Chile, Denmark, France, Greece, Hong Kong,
Hungary, India, Iran, Iraq, Japan, Korea, Mexico, South Africa,
Sweden, Taiwan, Thailand, United Kingdom, and United States,
based on the first author. Some of the papers include some
valuable database such as anisotropic strength ratio of natural
clays (2173), drained strength parameters from New Orleans
area (2280), over-consolidated Danish clays (2399), soft and
stiff Bangkok clays (2872), and rockfill materials (3011). Some
of the tested soils include special soils such as gas-hydrate
bearing ground in the Lake Baikal (2001), hydrophobic (non-
wettable) sand (2178), soil with diatom microfossils in Mexico
City (2239), coal mine debris (2782), and copper mine tailings
(2800). The report includes discussions related to the categories,
summarizes the papers, and highlights their major conclusions.
2 SHEAR STRENGTH
2.1.
Database of Strength and Stiffness Properties
In the design of getechnical structures, strength and stiffness
parameters obtained by well-documented database and/or
correlation with index properties are valuably utilized in the
early stage of design. This session introduces test database
including anisotropic undrained strength ratio, the comparison
of drained strength parameters obtained by traxial and direct
shear tests, drained strength parameters on OC Danish clay,
stiffness and strength parameters for Bangkok clays and rockfill
materials. For cohesive soils, strength parameters are correlated
with plasticity index and compared with the well-known
empirical correlations by Broker and Ireland (1965), Berre and
Bjerrum (1973), and Ladd et al. (1977). Strength and stiffness
parameters based on Duncan and Chang (1970) model were
obtained for Bangkok clay, Baghdad soil, and rockfill materials.
Six papers are in this topic and each paper is summarized as
below.
In paper 2137, Won developed the relation between anisotropic
strength ratio (K
s
=S
uE
/S
uC
) and plasticity index using the
collected database of 203 pairs of triaxial tests performed on NC
natural clays from 14 countries. For a consistent comparison,
data selection criteria were carefully established. He found that
the anisotrophy was strongly influenced by the definition of
failure in extension test, and no general trend of anisotrophy
with plasticity were observed, once the anisotrophy data are
grouped into their depositional environments (Fig.1). It is
interesting to note that this is opposite to the well-known trend
that anisotrophy decreases with plasticity index and he
emphasized the importance of careful consideration of site
specific characteristics, spatial variability, depositional and
post-depositional environments of the clay.
In geotechnical projects, triaxial and direct shear tests are often
used interchangeably to determine drained shear strength
parameters without regard to the potential difference. In paper
2280, Castellanos and Brandon performed a series of 63
consolidated undrained (CU) triaxial tests and 146 consolidated
drained (CD) direct shear tests on undisturbed samples from
New Orleans area to compare the shear strength parameters.
They showed that drained friction angles obtained from the CU
triaxial tests were considerably higher than those obtained from
CD direct shear tests in New Orleans area (Fig 2) because
1
