1680
Proceedings of the 18
th
International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013
Figure 21. Three dimensional finite element model (after Komiya).
Figure 22. Vertical displacement against the evolution of the box-
module construction (after Komiya).
The development of new construction techniques often raises
doubts about the expected settlements and stress conditions of
the structure. Numerical modelling and real cases monitoring, as
in Komiya, assist the general engineering practitioner to better
understand and trust the method.
Th
divided in six general topics
and reviewed briefly.
his report are an image of the information
e validity of the results and
egions to take a more active part in the
co
a role in underground construction and
all
ave to be described with the details. For example,
the
to properly explaining the steps and
bo
as installed, and how and
ho
ited and not
lim
8 CONCLUSIONS
is report presented an overview of the papers submitted for
the TC204 session of the 18
th
International Conference on Soil
Mechanics and Geotechnical Engineering. The papers covered
several aspects of “Underground Construction in Soft Ground”
and also some topics on rock tunnelling that were assigned to
this session. The 27 papers were
The comments on t
displayed on the papers, th
conclusions are responsibility of the authors of the papers. The
board of the TC204 committee would appreciate the
cooperation of all member societies were underground works
are going on at the moment, no paper was submitted from South
America, Eastern Europe, Africa, Middle East, Oceania, South
and Southeast Asia. We would like to invite the member
societies from these r
mmittee activities.
It is difficult to compare the papers with the papers presented
in Alexandria 4 year ago, because by then the papers were in
different themes. However, looking at the titles comparable
subjects are dealt with than 4 years ago. There are new
developments in underground construction: optical fibres are
used more than is suggested from the one paper presented here,
the increased computational power has led to complicated
numerical models (FEM and DEM) to simulate the various
interactions that play
ows probability analyses using these models. These topics are
already quite common on specialist conferences on underground
construction and probably will appear in the next general
conference.
Not all papers present the conditions for which the results
and data analysis have to be depicted, as numerical method,
mesh conditions, boundary conditions, calculation steps,
numerical tools, model preparation procedures, adopted model
scale, in flight actions etc. This complicates the application of
the results in other studies.
Also the procedures currently employed as the official and
correct tools to account for the underground construction related
phenomena h
β method for 2D finite element analysis of tunnel
construction that diminishes the excavation contour stress in
steps. The β value as well as how it was estimated or calibrated
should always be stated in the paper.
When more refined modelling procedures are used, even
more effort should be put in
undary conditions of the model. For example, in hydro-
mechanical analysis the initial conditions and especially how
the hydraulic and mechanical equilibrium equations are solved
radically affect how the results should be analysed.
The same lack of detailing can be said for the full scale or
real case monitoring. As presented in the monitoring topic, the
type of instrument, how and when it w
w often it was measured completely defines the range of
validity and reliability of the displayed results.
We expect that the this TC 204 session can bring significant
contributions to the underground space research and practice
fields, so that the important advantages of the use of the
underground space for our cities can be fully explo
ited by our technical capabilities.
9 ACKNOWLEDGEMENTS
The first author would like to acknowledge the financial support
of “Conselho Nacional de Desenvolvimento Científico e
Tecnológico – CNPq, Brasil”.
