Recent Evening Meetings

The BTS holds monthly evening meetings from September to June, generally on the third Thursday of the month. Unless otherwise stated, the meetings are at the Institution of Civil Engineers (ICE). Additional meetings are arranged by the BTS Young Members, by regional groups and as joint meetings with other societies. BTS Members can view recorded lectures on the ICE website for the first three months after the meeting. Thereafter the recordings are available for all to view and links are added below.

17/01/2019

BTS January Meeting: Challenges of the Design and Construction at the Gotthard Base Tunnel, Switzerland

The 57 km long Gotthard Base Tunnel, a 9 billion Euro project, is the world’s longest railway tunnel. The main Breakthrough took place on the 15th October 2010. All 151.8 km of the overall system are complete and the tunnel has been in operation since 2016. This lecture will provide some feedback from the construction difficulties and lessons learnt from the two 30 km long southern TBM drives from Bodio to Faido under overburden reaching a maximum of 2,400 meters. The project overcame a major fault zone, squeezing ground conditions and rock bursts. The TBM was blocked by a collapse, and had to cross water-carrying faults with rock and water temperatures reaching 48°C. The project also needed to cross weak and potentially risky zones like the Piora Basin. A section of the tunnel was enlarged after squeezing rock nearly blocked the TBM drive. Expected water pressure exceeding 160 bars required suitable pre investigation equipment. A waterproofing system with sheet membrane was installed along the whole tunnel length and extensive testing was carried out. The presentation will give a general overview and go deeper in selected topics.

Speaker(s)

Yves Boissonnas, Head of Tunnelling, EMEA, SIKA
04/02/2019

Joint BTSYM / ICE London Graduates and Students Committee lecture on Fire Safety

BOOKING IS REQUIRED. Please follow the link in the flyer. The lecture focus areas include: The legal requirements and duties imposed on employers and those responsible for managing fire safety. Guidance and reference documents. General Fire Precautions – What should be considered. Ensuring compliance and following best practice. The consequences of failure – offences and prosecution. Preplanning – Emergency Response.

Speaker(s)

David Harold, London Bridge Associates
07/02/2019

Joint BTS/MinSouth meeting. Salt Mining in Cheshire

Winsford Salt Mine: From Drill and Blast to Automated Continuous Mining, will explore the historic method of drill and blast; focusing on the move from continuous miners to the automation of the miners and the benefits of automation. Alternative Mine Uses (AMU’s) which are in place to reduce the weather effect of a winter de-icing business will also be discussed.

Speaker(s)

Gordon Dunn, Compass Minerals UK
19/02/2019

BTS February Meeting: Joint BGA/BTS meeting: Water and Tunnelling – lessons from 40 years of interesting problems.

David Hartwell was awarded the 13th Skempton medal by the BGA in 2018. In this lecture he will share his experience of ‘Water and Tunnelling - Lessons from 40 years of Interesting Problems’ The talk will highlight David’s experience in finding solutions to problems with groundwater associated with shafts and tunnels over the last 40 years. Along the way lessons were learnt, many of which do not appear in groundwater or soil mechanics text books. Two major projects will be highlighted: the Storebaelt tunnels in Denmark including pressure relief for the cross passages and the MOSES offshore dewatering scheme. The second major project was the recovery of the flooded Docklands Light Rail tunnel under the river Thames; freezing was considered but the scheme adopted included wells in the river and horizontal wells drilled from within the tunnel.

Speaker(s)

David Hartwell
20/02/2019

BTSYM February Meeting: Bangkok Orange Line Metro Project

The Bangkok Orange Line metro project comprises approximately 4 km of twin bored tunnels, three stations boxes, three ventilation shafts and a cut and cover tunnel. Arup are working on the detailed design of this project for a Thai D&B contractor called Italian-Thai Developments. This talk will cover several interesting technical aspects of the project, as well as an overview of life on an assignment in Thailand.

Speaker(s)

Paul Bailie, Arup
14/03/2019

BTS March Meeting: Elan Valley Aqueduct

The dams and conduits that form the Elan Valley Aqueduct system were built by Birmingham City Corporation between 1893 and 1904.The presentation will cover the history of the Victorian built Elan Valley Aqueduct with a look at some of the original construction techniques.The reasons why the new tunnels had to be built will be explained and the speakers will also describe the three tunnelling projects.

Speaker(s)

Ken MacGregor, Barhale; Paul Dennison, Severn Trent Water
04/04/2019

BTSYM April Meeting: Ottawa Light Rail

The confederation line in Ottawa comprises 15 stations and stops; its centrepiece is a 2.5km long tunnel with three underground stations below downtown Ottawa. The mined construction method for the stations was chosen in order to minimise the impact to the surface. The underground stations are located directly adjacent to existing, sensitive and sometimes historic buildings requiring detailed studies of risks during construction and risk mitigation measures. This presentation will look at the detail behind the design and subsequent construction of three large caverns at shallow depth and twin track running tunnels in rock.

Speaker(s)

Thomas Schwind, Technical Director, Dr. Sauer & Partners
18/04/2019

BTS April Meeting: Harding Prize

Presentations by the two finalists of this year's Harding Prize. The winner will be announced at the end of the meeting. The Harding Prize competition is named in honour of Sir Harold Harding, the founding Chairman of the BTS. The competition is open to young engineers aged 33 or under. Original paper submitted must address aspects of tunnelling which are considered of interest to the tunnelling industry, with the winning paper selected by a judging panel.

Speaker(s)

Eugene Kwan Lok Wong (University of Cambridge) presenting his paper: Deformation of framed structures due to tunnelling – a rational and practical assessment approach; and Sandeep Singh Nirmal (RITES Ltd), presenting his paper: Design of steel fiber reinforced concrete segment with curved radial joints
16/05/2019

BTS AGM and BTS May Meeting: The Brunel Museum's Original Thames Tunnel Drawings, What They Reveal

This meeting will look at the collection of original Thames Tunnel drawings. Described as the most significant Brunel drawings ever to enter the public domain and acquired by the Brunel Museum, Rotherhithe, they cover the period when Marc Isambard Brunel was developing and executing (with the help of his son Isambard Kingdom Brunel) the construction of his Thames Tunnel, the first in the world under a navigable waterway. They reveal how his ideas started and evolved, pulling in and then discarding other contemporary inventions; how he won the conviction of his shareholders, then won them over, time and time again; how his audacious self-confidence and patience was challenged from all directions yet was finally rewarded. His achievement gave others the confidence to tunnel in soft grounds everywhere and laid the foundations for urban Metro systems throughout the world. Pictorially and conceptually, it seems just a few short steps from the Brunel tunnelling shield to a modern tunnel boring machine.

Speaker(s)

Bryn Bird (M retired) Brunel Museum
06/06/2019

BTSYM June Meeting: Ground Movement due to Circular Shaft Construction in London Clay

Until recently, there were few well-documented case studies of circular shafts, which made it difficult to estimate reliable ground movements arising from such construction. Careful interpretation of field observations of ground surface settlement during construction of 27 circular shafts built for Crossrail, London Power Tunnels and Northern Line Extension, together with centrifuge model testing in the geotechnical centrifuge at Cambridge University, provides new insight into the ground movements arising from circular shaft construction. Dr Faustin and Professor Lord Mair present normalised charts to estimate the settlement due to circular shaft construction in London Clay with due consideration for different shaft geometries and construction methods.

20/06/2019

BTS June Meeting: Novaliches to Balara Aqueduct number four

The Novaliches to Balara Aqueduct number four (NBAQ4) project is part of Manila Water’s improvement and expansion initiatives and is one of the largest and most important infrastructure projects undertaken by them to date. The project involves the construction of a new intake facility at the La Mesa reservoir, a 7.3 kilometre tunnelled aqueduct and an outlet facility at the Balara Water Treatment Plant. The existing aqueduct system (aqueducts 1, 2, and 3) is required to continuously deliver 1600 million litres per day (MLD) of raw water to Balara Treatment Plants 1 and 2. Built in 1929, 1956 and 1968 respectively, they are nearing, if not already exceeding, the service life of 50 years for concrete structures. Through the project, the construction of a fourth aqueduct, which is designed to latest seismic standards, will enable the assessment and rehabilitation of the existing aqueducts. NBAQ4 will deliver water to approximately seven million people in Manila. The PhP 5.3 billion (USD 104 million) contract was awarded to a joint venture of CMC di Ravenna (Italy), First Balfour, Inc. (Philippines), and Chun Wo Engineering (Hong Kong) in August 2017.

Speaker(s)

Brendan Henry, Practice Leader - Tunnels and Underground Space, GHD
05/09/2019

BTSYM September Meeting: Evaluation of the bearing capacity of fibre reinforced concrete sections under fire exposure

The presentation will look at evaluation of the bearing capacity of fibre reinforced concrete (FRC) sections, without any traditional steel reinforcement, subjected to different values of the fire duration. The presentation will also provide an approach to define bending moment–axial force interaction envelopes, through an analytical model based on the direct integration of the hot or residual mechanical properties of the material, throughout the member cross section. Finally, a parametric survey, specifically related to tunnel segments, with different geometries and FRC materials will also be shared to highlight the worst (or better) scenarios.

Speaker(s)

PhD. Fabio Di Carlo, University of Rome "Tor Vergata"
19/09/2019

Thames Tideway West: The Design and Construction of Hammersmith Connection Tunnel

The Hammersmith Connection Tunnel forms part of the £4.2billion pound Thames Tideway scheme. The tunnel will intercept sewer flows from the Hammersmith Pumping Station, where on average 2 million m3 of untreated sewage is discharged into the River Thames each year. The design of the tunnel includes a sprayed concrete primary lining and cast in place secondary lining. The waterproofing philosophy adopted by the designer omitted the need for a traditional waterproof membrane between the primary and secondary linings. Instead a crystallisation agent was specified and incorporated in the primary lining, with the aim of improving the permeability of the section and watertighness of the sprayed concrete joints. The ability of this crystallization agent to limit water ingress was verified through a programme of pre-construction testing. This testing proved that an admixture dosage of 5kg/m3 was sufficient to satisfy the design. During the construction of the tunnel a number of key innovations were implemented by the project team. These included the use of a fully hydrostatic PLC driven formwork system to cast the tunnel secondary lining. The presentation with discuss this innovation plus others, whilst providing a detailed overview of both design and construction aspects of the works.

Speaker(s)

Ed Batty, Tunnels Agent (Bam Nuttall). Peter Coppenhall, Designer Representative (Morgan Sindall Engineering Solutions).
15/10/2019

Tunnelling Under 21st Century Building Structures is not easy: Bond Street Station Upgrade and the infamous case of Avon House

Please note this event is taking place at the University of Northumbria. Bond Street Station Upgrade was a complex project to extend the existing London Underground station with significant tunnelling and underground works to provide a new satellite ticket hall to the north of Oxford Street in London UK with an associated plethora of new passenger and station interchange tunnels. It was completed for Christmas 2017. Building Damage Assessment was undertaken to ensure that appropriate action was considered to reduce the effect on the above ground buildings from the ground movements arising from tunnelling works. One of these buildings, known as Avon House, is a 1930’s steel framed building, altered over a number of years by the insertion of transfer beams in the upper floors to allow a more open space for this important Oxford Street Retail area. Archive searches, supplemented by 3D Modelling and supplementary geotechnical and structural investigation, allowed the contractor, and his key sub-contractor, to make appropriate measures to protect the building during tunnelling. The presentation will describe the scheme, the building damage assessment and the mitigation taken from three members of the project team. Drinks and a buffet will be provided afterwards.

Speaker(s)

Andy Clarke, Costain; Richard Totty, Bachy Soletanche; Paul Perry, Hewson Consulting Engineers
17/10/2019

BTS October Meeting: Encountering a large Drift Filled Hollow on the Lee Tunnel

Drift Filled Hollows (‘scours’, ‘pingos’) are small to very large Quaternary ground features. They can extend deep into bedrock geology and are infilled with disturbed, metastable, superficial deposits and highly weathered bedrock. They present major risks to tunnelling and construction projects, yet predicting their location is extremely difficult. This presentation will explain the ground model and ground risk analysis developed for the 6.9km Lee Tunnel drive in east London. We will show how the Slurry TBM coped with a potentially catastrophic encounter with one of the largest of these features at over 50m below ground level. We will detail the urgent measures taken following this encounter, the behaviour of the crucial Northern Outfall Sewer, look at lessons learned, how DFH’s are formed, and how these features may be predicted in the future.

Speaker(s)

Tim Newman, Geotechnical Engineer (Jacobs), John Corcoran, Site manager (Morgan Sindall), Jackie Skipper, Senior Partner (Geotechnical Consulting Group)
07/11/2019

BTSYM: New Austrian Tunnelling Method in Hyperbaric Atmosphere

Christoph’s presentation will explore the challenges and innovative solutions associated with the application of New Austrian Tunnelling Method in hyperbaric atmosphere during the con-struction of Tunnel Karl-Friedrich-Strasse in Karlsruhe (Germany). The project – Shortlisted for NCE Tunnelling Festival’s ‘Innovation in Tunnel Excavation’ award – posed a unique challenge with its small overburden (approximately 7m), a poor geol-ogy consisting of gravel, sand and fine sand and layers of rolling gravel. Given the tunnel’s variable geometry (of up-to 180m² tunnel face; 15 m diameter), NATM was chosen as the preferred excavation method. However, due to the inner-city location and a very high water table, the excavation had to be carried out in a hyperbaric atmosphere, of circa 1.0 bar, which created special challenges for the application of wet mix shotcrete. Other challenges included: air losses and the corresponding air flow, and the presence of his-toric buildings along the path of the excavation (including a 125y old brick lined sewer directly above the tunnel alignment).

Speaker(s)

Christoph Huber, SCL Agent, BeMo Tunnelling
14/11/2019

Harding Memorial Lecture: Innovations for Tunnels - A Construction Company's View

How will Robotics and Digitalization shape the future of our tunnel industry? On three recent tunnel projects in Hong Kong, Bouygues Construction has developed and implemented innovative methodologies and tools to overcome major challenges that always come with mega-scale projects (see Flyer for details). The key driver behind these innovations is first and foremost safety and risk mitigation, but it turns out that these novelties actually brought significant improvements in operational performance as a side effect. A new era of innovation for our tunnelling industry is being explored - what will come next?

Speaker(s)

Thibaut Lockart, Bouygues Construction

Meetings held in previous years can be found in the Evening Meetings Archive.