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General Report of TC 211
Ground Improvement
Rapport général du TC 211
Amélioration des sols
Huybrechts N.
Belgian Building Research Institute, BBRI & KU Leuven, Belgium
Denies N.
Belgian Building Research Institute, BBRI, Belgium
ABSTRACT: The present General Report highlights the significant contributions of the papers of the Session of the XVIII ICSMGE
dedicated to Ground Improvement. All papers that have been reviewed are referred (in bold) in the General Report in order to provide
a balanced overview of the entire Technical Session.
This General Report discusses the latest developments and current researches in the field of Ground Improvement (GI) works. The
various GI techniques are classified considering the recent classification proposed by Chu et al. (2009). The papers are then tackled
according to the described GI technique and with regard to the topics that are assessed: execution process, mechanical characterization
of the treated material (in laboratory or in situ), case history, Quality Assurance/Quality Control (QA/QC) activities and design
aspects. Conceptual works and numerical modeling are supported by laboratory and field investigations - with in situ monitoring and
large scale tests. Finally, other references on the topics discussed are also given in the report.
RESUME : Le présent rapport général met en évidence les contributions significatives des articles de la session « amélioration des
sols » de la 18
ème
CIMSG. Tous les articles revus ont été référencés (en gras) dans le rapport général de manière à fournir une vue
d’ensemble équilibrée du contenu de cette session.
Ce rapport discute des derniers développements et des recherches actuelles dans le domaine des travaux d’amélioration des sols. Les
différentes techniques sont classées selon la récente classification proposée par Chu et al. (2009). Les articles sont ensuite abordés en
tenant compte de la technique d’exécution décrite et du sujet choisi par les auteurs : procédé d’exécution, caractérisation mécanique
du matériau traité (en laboratoire ou in situ), cas pratique, activités de contrôle et d’assurance du point de vue de la qualité et aspects
liés au dimensionnement. Les approches de conception et la modélisation numérique sont supportées par des recherches en laboratoire
et par l’expérience de chantier – apportée par le monitoring in situ et par les essais en grandeur réelle. Finalement, d’autres références
concernant le domaine de l’amélioration des sols sont aussi indiquées.
KEYWORDS: ground improvement/reinforcement, deep mixing, drainage, geosynthetics, grouting, inclusions, vacuum consolidation
1 INTRODUCTION
Ground improvement (GI) is one of the major topics in
geotechnical engineering. With regard to the world population
growth and in response to the expansion needs of our society, it
has become a fast growing discipline in civil engineering as an
alternative allowing construction on soft/weak/compressible
soils. Various specialized ground improvement conferences
have been frequently held in the past and recent years such as
the International Symposium on Ground Improvement
organized by the Technical Committee 211 of the ISSMGE and
recently held in Brussels (Denies and Huybrechts, 2012)
especially with more than 140 papers and 7 General Reports
focusing on GI works. A number of books covering various
topics on ground improvement have been also published in the
past. Most of them are referred in Chu et al. (2009). During the
last decades the importance of the ground improvement market
has enormously increased. New methods, tools and procedures
have been developed and applied in practice. In order to support
this evolution in a scientific way, research programs have been
and are being carried out worldwide, leading to more and better
insights and delivering the basis for the establishment of design
methods, quality control procedures and standards. As a result,
many technical papers on GI works were published in journals
and conference proceedings. It is not possible to mention all.
Separate lists are given on the TC211 website
(
. Major GI techniques have been
documented by the Working Groups of TC211 and are currently
available on this website.
TC211 adopts a classification system as shown in Table 1 in
Chu et al. (2009) with the following categories (and methods):
- A. GI without admixtures in non-cohesive soils or fill
materials (dynamic compaction, vibrocompaction,…)
- B. GI without admixtures in cohesive soils (Replacement,
preloading, vertical drains, vacuum consolidation,…)
- C. GI with admixtures or inclusions (Vibro replacement,
stone columns, sand compaction piles, rigid inclusions,…)
- D. GI with grouting type admixtures (Particulate and
chemical grouting, Deep mixing, jet grouting,…)
- E. Earth reinforcement (geosynthetics or MSE, ground
anchors, soil nails,…)
This classification is based on the broad trend of behaviors of
the ground to be improved and whether admixture is used or
not. In the following sections, the papers of the Session of the
XVIII ICSMGE dedicated to GI works will be reviewed
according to this classification and with regard to the topics that
are assessed: execution process, mechanical characterization of
the treated material, case history, QA/QC activities and design
aspects. It can already be noted that there is no paper
considering GI without admixtures in non-cohesive soils
(category A) in the present Technical Session.
