Hulme Prize 2015

This year I participated in Hulme Prize competition and my paper was shortlisted in Top 3 for presentation during a TUCSS seminar.

Hulme Prize presentation - invitation flyer

The Hulme Prize was set up by TUCSS in 1999 to honour Terry Hulme, Honorary Member of TUCSS, for his outstanding contribution to TUCSS and Tunnelling in Singapore. It is an annual competition for the best technical papers from young engineers or students (below 35) on any subject related to tunnelling and underground construction.

Hulme Prize paper presentation by Senthil Nath GT

Hulme Prize 2015 presentation in SMRT Auditorium

This paper can be accessed here.

Hulme Prize 2015

Breakthrough Magazine - Issue 1

First Issue of Breakthrough magazine was released this year during the ITA General Assemby meeting held during the WTC 2015 in Croatia. The issue could be accessed here.

Breakthrough Magazine - Issue 1

I was also featured in an interview column to talk about my 2nd level masters course at Politecnico di Torino, Italy.

Interview column

World Tunnel Congress 2015

In the month of May (22nd to 28th), I had the opportunity to attend the World Tunnel Congress in Dubrovnik, Croatia. This was my first World Tunnel Congress event and I had the opportunity to meet many friends from Italy, India, Germany and Singapore.

With my friend from Turin, Italy

ITA General Assembly

I had the opportunity to present my work titled "Probabilistic estimation of operating pressure for TBM Tunnelling". This paper basically presents probabilistic estimation of TBM operating pressure using Monte Carlo simulations as a part of design routine. This probabilistic approach would assist in risk assessment and will result in realistic face pressure values and thus avoid the operational disadvantages of over conservatively high face pressure values.

Face pressure estimation using Monte-Carlo Simulation

I also had the opportunity to get in touch with fellow ITA-YM members and was elected as the steering committee member of ITA-YM for a tenure of 2 years.

The Italian Art of Tunnelling

Literature survey will show that the fundamentals of modern tunnelling were already well understood during 19th and 20th century. The basic processes were almost completely understood by then and the only actual innovations have been in the use of new materials (shotcrete, high-strength steel, steel fibre reinforcements, admixtures, etc).

Based on the country of origin and underlying principles, there have been many classification of "tunnelling methods". It is quite obvious that differentiation of various "tunnelling methods" is sometimes difficult and they often overlap with each other. More often, a combination of "methods" offers an optimal solution for the problem at hand. However, for the case of classification, the classical tunnelling methods can be broadly divided into:

• German Tunnelling Method - Core method
• The English Tunnelling Method - Longitudinal beam/ trestle method
• Belgian Tunnelling Method - Underpinning method
• The (old) Austrian Tunnelling Method - Upraise tunnelling
• The New Austrian Tunnelling Method (NATM) - Thin-walled support to relieve ground pressure
• The Italian Tunnelling Method - ADECO-RS (Lunardi Method)

This post covers some salient points of the Italian tunnelling method.

Italian - Packing method in squeezing condition [4]

Traditionally, the Italian tunnelling method referred to packing method. It is used to overcome very difficult geological conditions (strongly squeezing rock with water ingress). Excavation is done in parts with immediate installation of packing material (even within the finished dimension of tunnel) and later broken out after ring closure. Later, the tunnelling method developed by Dr. Lunardi and Prof. Pelizza was referred as New Italian method, which was called ADECO-RS (Analysis of COntrolled DEformation in Rocks and Soils). The intention was to develop a process, which can conter the disadvantages of the NATM in regard to safety and cost-effectiveness in squeezing ground conditions.

While the Austrian method calls for partial excavation to increase face stability, the Italian method advocates full face excavation but with advance face support using methods like glass fibre anchors, jet grouting etc. This results in early ring closure than with the excavation of the entire cross-section in parts and keeps the deformation of the rock mass low. In addition, it also permits the use of large and powerful machines and hence faster production rates.

Lunardi [3] summarizes that the ADECO-RS approach emphasis to:

• Analyse the deformation response of the ground both ahead of and down from the face (using experimental, full scale, numerical, empirical tools etc)
• Controlling the susceptibility to deformation of the ground ahead of the face (advance core) by using appropriate stabilization techniques (various face stabilization techniques proposed in Dr. Lunardi's paper are shown below).

Choice of face stabilization methods [4]

While it may seem very similar to the New Austrian Method of measurement and control, Lunardi [3] clearly summarizes the difference in design and control using the pictures below:

Difference in analysis approach

Difference in control approach

Elaborate explanation about ADECO-RS method is given in Dr. Lunardi's book [1].

References:
[1] P. Lunardi, Design and Construction of Tunnels: Analysis of Controlled Deformations in Rock and Soils (ADECO-RS). Springer, 2008.

[2] Pelizza, S.; Peila, D.: Soil and Rock Reinforcements in Tunnelling. In: Tunneling and Underground Space Tech. 8 (1993), No. 3, S. 357–372.

[3] P. Lunardi, “The design and constrution of tunnels using the approach based on the analysis of controlled deformation in rock and soils,” Tunnels & Tunnelling International, no. May, pp. 3–30, 2000.

[4] Maidl, Bernhard, Markus Thewes, and Ulrich Maidl. Handbook of Tunnel Engineering I: Structures and Methods. Vol. 1. John Wiley & Sons, 2013.