TC206 Observational Method

Observational Method

Host Member Society: United Kingdom

Short name: Observationall Method (TC206) - Terms of Reference - approved

Contact: TC206 Secretary, Amit Srivastava

TC-206 External Website: tc206issmge

BGA Half-day Mini-Symposium on Observational Method, 2024

British Geotechnical Association Event: Half-day Mini-Symposium on Observational Method (6th February 2024, London, UK) 

The Observational Method (OM) in ground engineering is a continuous, managed, integrated process of design, construction control, monitoring and r

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NCE Tunnelling Conference - Debate discussion, 2023

In the year 2023, on 7th December, New Civil Engineer (NCE) conducted event that brought together the tunnelling community for an interactive and immersive day of case studies. Details can be accessed at (


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Smart Geotechnics Conference, 2023

In the year 2023, on 5th October, Ground Engineering ( conducted 2nd Smart Geotechnics conference at Victoria Park Plaza, London. The main facus of the conference was to bring together experts working in the field of GE Instrumentation and Monitoring, ge

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ISSMGE Interactive Talk TC206, 2023

In the year 2023, on 11th October 2023, the eleventh episode of International Interactive Technical Talk was launched by TC206. Duncan Nicholson, Tony O'Brien, Ying Chen and Anyang Yaw Michael  with Dr. Marc Ballouz discussed about Observational Method. The recorded vide

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4th International Symposium on Machine Learning and Big Data in Geoscience, 2023

In the year 2023, dated 29th August 1st Sept., the 4th International Symposium of Machine Learning and Big Data in Geoscience & Geoengineering (ISMLG) was held at University College Cork, Ireland. The theme of the symposium was Data-centric solutions for reshaping the next ge

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11th International Symposium on Field Monitoring in Geomechanics, September 2022

In the year 2022, the 11th International Symposium on Field Monitoring in Geomechanics was held at Imperial College London. Symposium themes included topics related to Tunnels and Underground Spaces, Bridges and Transport Infrastructure, Dams and Embankments, Slopes and Earthwork

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ISSMGE Interactive Technical Talk Episode 11: Observational Method (TC206)

The eleventh episode of International Interactive Technical Talk has just been launched and is supported by TC206. Duncan Nicholson, Tony O'Brien, Ying Chen and Anyang Yaw Michael are discussing with Dr. Marc Ballouz about Observational Method.

Watch ISSMGE Interactive Tec

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New Book by Powderham and O'Brien - The Observational Method in Civil Engineering

There is a new book on the Observational Method by Alan Powderham and Tony O'Brien entitled The Observational Method in Civil Engineering, which may be of interest to members.

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Objective 1:  Develop and disseminate knowledge and practice on the Observational Method (OM).

  • The Observational Method process was introduced by Peck (1969) in his Rankine Lecture  (Geotechnique,19,N0 2, 171 -187).
  • A definition for the OM is set out in the CIRIA R185 (1999):-
    • The Observational Method in ground engineering is a continuous, managed, integrated process of design, construction control, monitoring and review that enables previously defined modifications to be incorporated during or after construction as appropriate.  
    • The objective is to achieve greater overall economy without compromising safety.  The method can be adopted from the inception of a project, or later if benefits are identified
  • The OM has also been recognised by recent codes eg Eurocode and ISO.
  • An over-arching theme for the TC206 would be to develop the breadth of OM applications in different branches of Civil Engineering as a method of dealing with risk and uncertainty. The goal is to develop a common simple framework and definition across Civil Engineering.

Objective 2: Establish guidelines and technical recommendations within OM framework.

  • Currently the Eurocode is the most advanced standard dealing with the Observational Method. This should be extended to other codes and tested on projects.
  • Part of this objective is to introduce OM into parallel codes and disciplines, such as Tunnelling and Environmental Engineering. Key features to address are the large uncertainties in design parameters, modelling and construction methods. Instrumentation and data handling are equally important.

Objective 3: Play an active role in conferences organised by ISSMGE

  • TC206 can contribute to sessions or workshops at conferences organised by other ISSMGE committees. TC206 does not intend to organise separate conferences. The aim is to interact in the conferences to advance a clear OM process. The objective is to reduce the use of the trial and error approach, which is potentially dangerous.
  • ISSMGE case history conferences have much in common with OM. The back analysis or inverse analysis of case histories is key to assessing the most probable parameters. There is a need to promote papers which rigorously apply the OM framework. Contingency plans and mitigation measures are important to control safety. The TC206 will promote and encourage such papers.

Objective 4 - Interact with industry and overlapping groups working with OM.

  • One of the big barriers to OM is how to implement the OM into civil engineering contracts. It is important to identify parallel disciplines which use the OM process, but have a different frameworks and terminology. Tunnelling and rock mechanics are examples. What lessons can be learnt exchanging different views and approaches?
  • To develop the TC206 OM process, it is important to engage with other TCs regarding: -
    • Civil engineering applications that are appropriate for OM.
    • Site investigations and soil parameters - where a wide range of uncertainty exists. (TC 102)
    • Numerical modelling and its limitations links with back analysis assumptions. (TC103)
    • Instrumentation systems The data accuracy is very important.  (TC220)
    • Data handling, statistics and risk/safety assessment Machine learning and real time back analysis or inverse analysis is increasingly important to support the construction review stage.
    • The reassessment of conventional designs based on the back analysed most probable parameters. Establish the degree of conservatism and potential for material reduction.
    • The process of defining trigger values and contingency plans should be developed.
    • The contractual framework to use the OM is important to establish.

# Type Full Name Country
1 Chair Duncan Nicholson United Kingdom
2 Vice Chair Ying Chen United Kingdom
3 Secretary Amit Srivastava India
4 Corresponding Member Hock Liong Liew United Kingdom
5 Nominated Member Paweł Popielski Poland
6 Nominated Member Ravi Kiran Vaidya India
7 Corresponding Member B. Manna India
8 Corresponding Member Ankesh Kumar India
9 Nominated Member Christopher Menkiti United Kingdom
10 Nominated Member David Zhang Australia
11 Nominated Member Johan Spross Sweden
12 Nominated Member Tomasz Godlewski Poland
13 Corresponding Member Jinsong Huang Australia
14 Corresponding Member Andrew Ridley United Kingdom
15 Nominated Member B.K. Maheshwari India
16 Nominated Member Franz Tschuchnigg Austria
17 Nominated Member Miguel Conceição Portugal
18 Nominated Member Ayfer Erken Turkey
19 Corresponding Member Leen De Vos Belgium
20 Nominated Member Mehmet Berilgen Turkey
21 Corresponding Member Aliasger Haiderali United Kingdom
22 Nominated Member GUSTAVO ROCHA VIANNA Brazil
23 Nominated Member Habib Shahnazari Iran
24 Corresponding Member Truong Le United Kingdom
25 Nominated Member Noel Huybrechts Belgium
26 Nominated Member Zhiguo Yan China
27 Corresponding Member Gavin Toh Hong Kong Special Administrative Region
28 Corresponding Member Augus Maxwell Hong Kong Special Administrative Region
29 Corresponding Member James Sze Hong Kong Special Administrative Region
30 Corresponding Member Agustin Ruiz Lopez United Kingdom
31 Nominated Member Tara Wood Sweden
32 Nominated Member Christian Moormann Germany
33 Corresponding Member Ki-Tae Chang South Korea
34 Nominated Member Antonio Cañavate Grimal Spain
35 Nominated Member Ignasi Aliguer Piferrer Spain
36 Nominated Member Calogero Valore Italy
37 Nominated Member Mandy Korff Netherlands
38 Nominated Member Sebastiano Rampello Italy
39 Nominated Member Umur Salih OKYAY France
40 Nominated Member Tony O'Brien United Kingdom

The following “planned activities” are proposed by the TC206:-

  1. Contact TC members  (Objective 1) - The TC Members will write short CV’s summarising their OM experience and papers they have written.  The TC will then:-
    1. Identify gaps in the TC skill base and identify new members.
    2. Debate the difference in terminology between “Interactive Design” and “Observational Method” in (two) conference calls with the members.
    3. Identify a TC secretary from outside Europe with OM experience.

The timeframe for this is 3 months

  1. Establish Guidelines and Standards  (Objective 2) – Review the current use of OM in guides and design specifications.  

A developing area is real time back analysis using Bayesian methods to automate the redesign process.  Procedures need to be developed and tested.


A reference list and comparisons will be made.  The time frame for this is 6 months and parallels Eurocode updates.


  1. Conference Organised by ISSMGE  (Objective 3) – The OM is unlikely to warrant a conference by itself.  However, OM fits well with other ISSMGE conferences which have a large component of back analysis.  The following is planned:-
    1. Present at the ISSMGE Conf Sydney (Sept 2021) on the changes planned for the TC.
    2. Promote a clear framework and design process to be used with OM. 
    3. Organise sessions / participate in conferences on back analysis in geotechnics, including soil parameter assessment leading to most probable and characteristic parameters, tunnelling, environmental geotechnics, instrumentation, risk assessment, statistics and risk. 


  1. Interaction with Industry and other TC’s  (Objective 4) – To improve interaction with industry the TC206 needs to interact with construction contracts.  This will require contractor and client input.  The design and build contracts are possibly the easiest way to interact using value engineering clauses.  Initially the TC206 will encourage experienced contractors to join TC206.  The papers will be written to define contract options for OM input.

The Objective 4 identifies some of the other TC’s to interact with.The Chair/members of TC206 are individually interacting with the relevant TC’s and report back to the whole TC. From those contacts a proposal for a joint meeting is developed taking place at a ISSMGE conference.


The deliverables include:-

Objective 1 deliverables - An active TC206 group and clarification on ID / OM with a web site. – 3 months

Objective 2 deliverables – A coordinated approach to OM through different guides and codes.  The redrafting of the Eurocode is in progress.  The OM aspects will be disseminated - 6 months.

Objective 3 deliverable - Joint ISSMGE Conferences with other TC particularly on back analysis. - The ISSMGE 2021 will be a key target to link with other TC’s.

Objective 4 deliverable – A contractual framework for the use of OM by industry.  The first step in to identify key contractors and clients.  3 months – a contractual framework would take about a year.

Contact Technical Committee : Observational Method

This message will be sent to TC206 Observational Method officers