Consortium for Research into Congested Underground Space (CoRCUS)

About CoRCUS

The Consortium for Research into Congested Underground Space (CoRCUS) have extensive experience – and a sound appreciation – of the challenges posed by new construction in congested underground spaces in the urban environment.

Working around existing infrastructure and buried assets is increasingly unavoidable in urban environments, and the need to protect these assets from damage can significantly influence, and sometimes hinder, the development of new schemes. These issues affect the majority of new underground construction schemes in urban areas; any new shafts or tunnels needed for such an enterprise are necessarily in close proximity to existing station structures.

Furthering the understanding of the ground’s response to congested underground construction events and the assessment of the impact of new construction on existing assets is a complex task.  It is necessary to understand the geometry of the new and existing assets, proposed construction methodology, material properties for the assets and the surrounding soil, carbon impact and the condition of the existing assets.

Simplified assessment methods exist but by their very nature these are inherently conservative, and asset owners are inevitably cautious; a better understanding of the mechanisms involved would potentially allow this level of conservatism to be reduced. The vision of this Consortium is to conduct research, informed by practice, which will further our understanding and engineering capabilities in this important area.

News and events

• CoRCUS meeting 1(a) – 27^th January, 2021
• CoRCUS meeting 1(b) – 27^th September, 2021
• CoRCUS meeting 2 – 24^th March, 2022
• CoRCUS meeting 3 – 17^th January, 2023
• CoRCUS meeting 4 – 29^th June, 2023
• CoRCUS meeting 5 – 20^th September, 2023
• CoRCUS meeting 6 –  5^th March, 2024

Funding and support from:

Consortium partners

• Dr Sam Divall – Chair

Sam is a Senior Lecturer in Geotechnical Engineering at City. Dr Divall has published papers mostly in the area of the ground's response to construction in a congested underground space. Dr Divall has worked on many collaborative research projects, both numerical and physical modelling based. He is a Chartered Civil Engineer with the Institution of Civil Engineers (ICE). He is also an invited member of the ISSMGE Technical Committee for Physical Modelling in Geotechnics (TC104). He was also Vice-chair for the 9th International Conference on Physical Modelling in Geotechnics (ICPMG 2018), co-editor of the proceedings. Dr Divall has won the British Geotechnical Association’s (BGA) Young Geotechnical Engineers’ Symposium Award (2012) and has been an invited speaker at many international conferences. His research outputs include 11 journal articles, 18 international conference proceedings, co-editor of one international conference proceedings.

• Dr Neil Philips – Vice-chair (COWI)

Neil is a Senior Tunnel Engineer at COWI with 15 years’ experience within the tunnelling and underground space sector. He has worked on many projects ranging from the construction of shafts and pipe jacks, up to large infrastructure tunnelling works. He obtained a Masters degree and PhD investigating the understanding and optimisation of slurry tunnelling; which were sponsored by the tunnelling industry. He is also a Chartered Civil Engineer with the Institution of Civil Engineers (ICE).

Academic Partners

• Prof Michael Davies (City, University of London)
• Prof Sarah Stallebrass (City, University of London)
• Prof Neil Taylor (City, University of London)
• Dr Miguel Bravo Haro (City, University of London)
• Prof Jamie Standing (Imperial College)
• Dr Emilio Bilotta (University of Napoli Federico II, Italy)
• Dr Tra Nguyen (Vietnam Aviation Academy, Ho Chi Minh City, Vietnam)
• Dr Binh Le (Anglia Ruskin University)

Industry Partners

• Paul Gallagher - Managing Director Designate (Joseph Gallagher limited)
• Hilary Skinner - Technical Director (COWI)
• Dr Vicky Potts - Technical Director (COWI)
• Jag Chima - Technical Director (COWI)
• Paul Challinor - Senior Construction Manager at STRABAG (SCS Railways)
• Dr Richard Goodey - Associate (A-squared Studio Engineers Ltd)
• Maddy Losito - Project Engineer (TfL Engineering)
• Dr Njemile Faustin – Principal Geotechnical Engineer (AECOM)
• Anita Wu - Associate (London Bridge Associates)
• Dr Eric Ritchie - Innovation Manager (Ferrovial)
• Dr Chris Menkiti - Senior Partner (GCG LLP)
• Ross Dimmock - Vice President Tunnelling (Normet Group)

Current projects

• Title: Reducing the risk of long-term damage to buildings caused by tunnelling-induced settlement in soils in low lying South East Asian cities (successfully completed)

Supported by: UKRI - Global Challenges Research Fund

Description: The project permitted experts in tunnelling in urban environment at City, University of London to establish collaborative work with engineers and academics in Vietnam, directly, towards the specific issue of tunnelling in the typical soils found in this developing nation. The two teams will work together as co-creators of this research in order to solve problems commonly encountered in South East Asia where many large cities are located in areas that are geologically similar to Ho Chi Minh City. In addition, knowledge transfer of the outcomes of research leading to a greater understating of the engineering challenges associated with tunnelling in challenging ground conditions will enhance the opportunity for UK based engineering consultants to engage in projects overseas, thus enhancing UK invisible exports.

• Title: Quantifying long-term tunnelling-induced ground movements in fine-grained soils (on-going)

Description: Tunnel construction inevitably leads to ground movements that potentially can damage surface and subsurface structures. It is therefore important, when designing tunnels in urban environments, that the resulting ground response is predicted reliably. Short-term ground movements are directly attributed to the excavation and can be predicted reliably with confidence. However, there is a dearth of guidance on predicting the magnitude and extent of long-term tunnelling-induced ground movements. This works aims to establish the fundamental mechanisms associated with long-term tunnelling-induced ground response, utilising geotechnical centrifuge experiments that simulate the whole-life behaviour of a prototype lined tunnel constructed in fine grained soils.

• Title: An investigation into underground openings from shafts to tunnels (on-going PhD).  Supported by: COWI and Joseph Gallagher Limited.

Description: During tunnelling works there is the requirement for a connection to other buried infrastructure (e.g. vent shaft or pedestrian tunnel). The operation of connecting the tunnel requires the formation of an opening, the partial demolition of the shaft, disturbing the loading and support equilibrium, and risking the integrity of the structure. This leads to the requirement for temporary works, which are typically omitted from the Permanent Works Designer’s scope, often falling to the Tunnelling Contractor as a temporary works item. Consideration must be given on how ground loads carried by the shaft are transmitted around the newly formed opening. However, this leads to conservative solutions being adopted. There are limited guidance on approaches to the design of an opening in a shaft and result in methods such as wished in place being used. Initially, a comprehensive review of current practice (including an industrial partners sharing method statements).

PhD candidate: Mayda Ucur

• Title: Reducing tunnel volume loss using data processing techniques (on-going PhD). Supported by: Skanska Costain STRABAG Joint Venture on HS2

The project will be, firstly, collating two Big Data sets captured during tunnelling works (settlement and TBM driving data) and conducting a series of interrogations to establish the most important variables. The next stage is to employ data processing techniques to create the relationships necessary to predict settlements for a given TBM data set. The aim for this section of the proposed work will be to predict settlement data further along a route using TBM data from earlier in the drive.  The validation of the modelling will be extended by a series of experiments with carefully controlled conditions which will in turn supply more data for the predictive model. The data will be made available if requested for alternative analyses to be conducted by HS2 or its nominated suppliers. The model and all of the HS2 tunnelling data will be not only shared with HS2 and its nominated suppliers, but it will also be wholly non-proprietary and published as part of the academic record and learning legacy of this project.

PhD candidate: currently recruiting.

Civil Engineering lab

Purpose-built laboratory housing a recently refurbished Acutronic 661, 40 g-tonne, geotechnical centrifuge with state of the art instrumentation, image capture, and hydraulic, electrical and optical slip rings.

The centrifuge facility is operated by a highly experienced team of researchers using actuators, motors and syringe pumps to carefully simulate geotechnical events in flight. It is accompanied by space for model preparation, including consolidation presses to create clay soil beds for testing and additional loading frames for 1g testing.

Element testing laboratory containing automated stress path triaxial apparatus, shear box apparatus, a Bishop ring shear apparatus and a high pressure triaxial cell. This facility also provides space for classification tests and a range of customised tests investigating soil slurries, bentonite and the effect of adding polymer.