you you and we’ve got a terrific talk tonight
from The Young Turks my goodness we do have the bright and
beautiful to talk to you tonight and what what few of what changes they’re
going to see in in their future careers so Hammersmith connection tunnel and our
two Young Turks Peter cop and halt Morgan symbol engineering solutions
Peter works for Morgan symbol engineering solutions and engineering
consultancy within Morgan symbol infrastructure
he’s a chartered civil engineer with over six years of experience in
tunneling and was one of the first students to obtain the MSC tunneling and
underground space from Warwick University he previously worked on the
construction of the ICL tunnels at the cross sea 310 contract and for the last
two years has worked as the designers representative on Thames Tideway West at
battey of BAM Nuttall that works for the major projects division of BAM Nuttall
he’s a chartered civil engineer with over seven years of site experience Ed’s
career began as a TBM shift engineer on Ed’s
career began as a TBM shift engineer on Coast rail contract c300 for ten his
experience on this TBM was the focus of his Harding prize paper which won the
competition in 2014 over the last seven years it has been exposed to various
types of tunneling including hand works as CL primary and secondary lining that
is currently working on the Frogmore connection tunnel where he holds the
position of tunnel manager but just just before we start and if you could make
sure any mobile portable devices were switched to silent so there are two
Young Turks get a clean run of it there are no fire alarms or any other
stuff, so get a fire alarm I guess it’s a so a good idea to leave the building we’ve got a few more coming in and then
went once once we’ve sat down but I the seats are at the front buddy you can come
down here don’t don’t be shy you’re not normally good evening ladies and gentlemen
tonight we’re going to talk to you about the Thames Tideway tunnel and the focus
of our presentation will be on the Hammersmith Lexington I’ll start off
with the problem and it’s a problem I’m sure you’re all aware of so Joseph
puzzle jet bill asks who is in the 1850s so Joseph
puzzle jet bill asks who is in the 1850s ? 1 There are now 9 million people flushing and washing in our city and
Buzzle Jets sewers are full to the brim with every downpour these sewers
overflow known of combined sewer overflows and
they overflow into the River Thames this 6 happens on average once per week and the
result thirty-nine million tons of raw sewage entering our river every year so
how to solve this second big stink or luckily for all of us in this room the
solution came in the form of a 25 kilometer long leg mentally lying to
know the tunnel starts acting in the West and spans across London through two
Admirals pumping station in the east as it spans across London it picks up 34 of
the worst offending csos once operation operational instead of a sewage entering
the river it will make its way to the tunnel where it will be stored and
transported back some treatment works for safe treatment give him a scale of the scheme the
tunnel was split up into three key contracts namely west central and east the Western contract contract see 405
was awarded to the BAM Nuttall Morgan sindelle and Balfour Beatty joint
venture in September 2015 it was procured using an NEC option C single
phase design construct contract the joint venturers freaky designers
undertaking their design then I’ve shown on this slide a point of note is that
Morgan’s and engineering solutions are responsible for the shaft internal
temporary and permanent to work design the scope of C 405 West comprises seven
key shafts most of which have been designed and constructed using SLE
linings five of those seven structures are now complete and over 15,000 cubes
RCL have been applied in that process our main drive is a six point nine
kilometer long single bore of seven point one meters internal diameter a
drive starts in Tamworth Road and goes west towards acting storm tanks our main
tunnel TBM rachel is about four hundred and fifty rings in she’s got a long way
to go but she’s making good progress she’s constructing our tunnel with a
look up of 1.4 millimeters per meter so far she has churned up and spat out over
70,000 tons of London clay from beneath the river the scope of west also
involves four smaller connection tunnels and these have been constructed using a
range of methods including mechanized tunneling pipe track and SEL the focus
of our presentation will be on the hammersmith pumping station and you can
see that on the slide now so to set the scene with Hammersmith I’d like to self
of this picture of five operatives at work these five highly skilled men have
been given the grueling task of working in the live image and all of the
Hammersmith pumping station they’re working in the close proximity
of raw sewage mixed with discarded wet wipes and sanitary products the works
must be undertaken while keeping the pumping station life as if it goes
offline this may result in the catastrophic flooding of West London the
endlich channel is just one key element of this asset of national importance it
channels suit songs overleaf relief flows into the pumping station where
eight storm water pipe that some water pumps pick them up and pump them out
into the Thames the works in the channel are planned in such a way that the men
and their tools can be removed quickly in the event of the storm the channel is
80 metres deep five metres wide 25 metres long when storm relief flows make the way to
Hammersmith then to the inlet channel of a flow rate of up to 30 cubic meters per
second now to put that into context this great theater is 80 meters deep it is 12
meters wide and it is 8 meters high it therefore has a volume of 1,700 cubic
meters I’d like to you or to imagine that the storm flows entering this room
and not the Hammersmith pumping station on entry to the room it would take just
9 seconds for you all to be swimming in sewage in 55 seconds later the room
would be full and we’ve been serious trouble the hammersmith site was signed
over to the BM B joint venture in the summer of 2016 and works have been going
on since a site is surrounded by a number of key residential receptors and
sensitive assets so she’s Frank Frank Banfield Park to
the north and the residents of Chancellor’s old and Fullman reach to
the south west and east the works at how much was her very typical to oversee
ourselves on the scheme their purpose is to transfer the flows from the pumping
station into the main tunnel and that is achieved for an interception chamber a
connection to a culvert a drop shaft and a connection tunnel the interception
chambers being constructed directly adjacent to B in that tunnel and the
works here progressing well the team for now it’s the weight of over 4,000 tons
of material I have just started the internal structures once complete the
inception chamber wall houses series of penstock gates which will control flows
into the new tide wave scheme the connection to know which 300 meters long
and juts out into the center of the turns where it needs to main to long the
tunnel passes under a number of key assets including the river wall two
blocks of luxury flats with an average value of one point four million are now
past year over to Peter who will take you for the design of the works
before you started anybody stood at the back there’s seats at the front here if
you want to she could come down maybe and I see that somebody actually stood
behind paraponera plenty don’t be shy there plenty of seats to the front okay before I take you free design I
would take you through to Georgie of Hammersmith from the initial ground
investigation that was carried out by Thames Tideway and outlined in gbr
report you can see there’s only a few bore holes that were so important being
be undertook further ground investigation to confirm that the
consistency of the ground and of the GPR and from this initial ground
investigation it was consistent with what the GPR stated the geology
comprises of made ground overlying rivers terraced deposits the London clay
formation and the Lambeth group the connection tunnel was situated in the
ideal location it’s in the middle of London clay formation it has a 90 meter
cover towards the Lambeth group and it has 20 metres clay cover to the crown of
the tunnel as it passes out underneath a river Thames from the ground
investigation data we’re able to tell that the piezometric level was recorded
at 100 metres above tunnel datum but for the purpose of design 105 metres above
tunnel Dayton has been assumed which is consistent with the existing ground
level here is the overview of the client reference design that shows the key
requirements for the design development we have a 35 meter deep shaft with 11
metres in turn odometer a 48 metre long duration chamber with a five point one
meter internal diameter and a 250 meter long connection tunnel were for me two
internal diameter but if the tunnel and the sheriff required the use of a
primary in the secondary lining and the use of a waterproof membrane as well so
comply with the streets water ingress requirements there is a B&B MSC s
innovation to remove this waterproofing which required consent from tender
territory as well there’s a 3.5 meter internal dam to
stainless steel tube in the middle of the shaft the purpose of this is to
transport the sewage down from the top of the shaft to dept of shaft in a
harmless manner otherwise if the surge came down itself it would come crashing
down to the floor and it damaged the structure the way this works is by
creating a vortex with in this tube so the surge comes towards the top of the
tube and it spins down the shaft all the way down to the bottom in a harmless
manner now we’ve undertaken a number of
computational fluid dynamic models and real-life scale tests undertaken just to
verify this assumption and this short video shows how the series will travel
along the connection cover and down the shaft as a vortex the next video I’m
about to show will show another scaled down model which is about 1/10 which is
one tenth of the size of the actual shaft and just to know as the water
comes out at the bottom of the vortex you’ll see the amount of air that is
generated in this he says we go along the connection
Grover down the vortex so as your a note from that video
there’s a lot of air that’s generated under bottom after the vortex and it’s
really important that any of this trapped air is removed from the system
so it doesn’t cause damage in the future so this is where the duration chamber
and the vent pipe come into play as a sewage movies from the shaft means a
duration chamber there’s a flow restrictor at the end of the duration
chamber which basically holds up the sewage just long enough for the to allow
the air to basically rise to the surface and leave the sewage they then travels
along the top of duration chamber out of the vent pipe and back up to the surface
in the harmless manner for the design the works information several key
requirements 120 years design life to be able to accommodate the predicted sewage
flows and the surge pressures that would be experienced by both the shaft and the
tunnel to comply with districts water ingress requirements and the sewage
egress requirements to minimize the requirement for repair replacement and
maintenance of the works as well the finally the design construction must
stay within the boundaries that are stipulated by the development consent
order and in terms of Hammersmith this is very tight which Edward touch upon
later as already mentioned the water ingress of requirements are very strict
as you can see here the maximum acceptable water ingress into the
completed shafts and the tunnels are no point 1 litres per meter square per day
on average or naught point 2 litres per meter squared per day over any 10 meter
section part 2 of this clause also states there is limited damp patches
which is defined as discoloration that part of the surface of the lining and
this part can be open to interpretation and has caused issues as well on one of
issues it’s caused the point of contention along the way our area also states that limitations
are super applied to both ingress and egress so we have to ensure that the
water doesn’t come in and the series doesn’t escape and this is verified by
observation and measurement within the tunnel and outside of the tunnel is
verified by calculation and 1/2 in the ground water quality in the local area
these strict requirements have been outlined by toad way it’s ensure that
the maintenance operations costs of the system is minimized across the whole of
the Thames Tideway scheme I will now give you an overview of the design
development gate process which is very similar to the RIBA stages as a
design-build contract the contracts has been heavily involved for our all of the
stages from gates 1 to 6 and they’ve helped develop the design for the use of
several constructibility meetings a key stage here is gate free where we had
interdisciplinary reviews these were the likes of micro hydraulics architecture
and landscape operations and maintenance and many more and it’s key that this was
undertaken prior to progressing on to detail design also it gave three this is
the first instance that the Thames Tideway design engineering team and a
desiring Authority where were to comment and approve design and the initial
design concept BIM has been used throughout the project to help
coordinate designs and provide a single point of reference for information this
has been available for all parties involved in the contract the hammersmith
design started in September 2015 along with the start of the contract the
primary lining for just a shaft finished in December 2017 and 4d for the tunnel
the primary lining and the second July and finished in April 2018 so not very
long ago the shafts Eckrich aligning is closer to being finished and the
internal structures the vortex and the cover slab are still ongoing here’s an overview of the gate 5 design
each of elements they have been specified here are to comply with
durability requirements in terms of the mix design and the design crack whips
this is in order to make sure that it meets these tight water ingress
requirements the first stage you can see here is the seeking par wall which is
highlighted in red and listen a was the initial shaft excavation in various
deposits while cutting off and the water ingress from the water been gravels the
second pile wall is only is only temporary works however it will remain
in place for the length the duration of the structure itself the shaft primary
liner is recreated with still 5 reinforced SCL with 1.2 meter advances
as it progresses the shava shava Milani and the SEO allowed flexibility so
therefore in order to minimize the thicknesses and also demerit material
consumed and as we progressed down to the bottom of the shaft also it has an
elliptical shape which incorporates the tunnel opening portal there’s a
thickening section here which uses a traditional and barbed reinforcement
which is also to be sprayed in at the bottom of the shaft is the base slab
this is a 2 point 2 meter thick base slab which is designed as a flattop
structural dome and this resists the long-term pressures of uplift from the
geostatic and water pressures the shaft secretary lining has hybrid
reinforcement so it utilizes high-performance steel fibers and
traditional bar reinforcement it’s up to 800 millimeters thick in places the
traditional bar reinforcement helps to tie in the accommodating structures in
inside of the shaft so despising the any of the internal
structures and vortex tube itself the tunnel primary lining is also installed
in a similar manner to the shaft that still fiber reinforced and is restored
in one meter sections and it’s 325 millimeters thick the shaft second relining is 250
millimeters thick and design design follows the smart shell technique which
removes the requirement for traditional bar reinforcement and uses
high-performance steel fibers in this case which to drum x5d fibers to replace
any of that reinforcement and this technique was proven before hand on the
tunnel projects by full-scale tests and has been verified since there had been
some lessons learned from the lead on a project such as we’ve reduced the length
of the shutter from 30 meters down to 6 meters
I’m also ensuring the shutters pulled were for hydrostatic pressure as well there are two principal design load
cases which are calculated from the dominant loading conditions they’re
experienced so in case one is the highest external pressures that’ll be
that shaft and the tons of experience as you can see it will have geostatic
pressures from the from the ground and it also have the highest ground water
pressure so in this circumstance at 100 105 meters above the tunnel dating this
will oppose the shaft the shaft and the tunnel where is weakest state which and
in the worst load condition which is when the shaft internal empty this will
incorporate the maximum bending moments and stresses that are anticipated to
develop in the structure so this over this therefore overall governs the
design of the shaft and the tunnels for design case 1 as well an additional
surcharge has been placed them on the surface and it’s just represents any
future required developments that will be undertaken design case to the highest internal
pressures that will be experienced so the ground loading stays the same the
ground water pressure will be reduced to his lowest known level and the shaft and
tunnel itself will before and this represents a surge event to be able to
understand how the primary and secondary ins work we need to understand how to
installed the primary lining you first isn’t stored sequentially as mentioned
one point to me advances or one me to advances in the tunnel and this takes
all the initial groundwater loading in order group all the ground pressure as
well the second G lining is then the stored
in a stress-free environment however over time additional external
pressures are experienced by the shaft and by the tunnel this result this is
resulting from clay consolidation changes in groundwater seepage the surge
events and it causes the primary line to deform which then activates the
secondary lining which results in the two linings working together and a
combined manner when in operation the primary line will always remain in
compression and the second aligning would go into tension in the surge event this shows a typical section of the
completed lining we have a 75 mil initial steel fiber reinforced ACL this
is for the immediate ground support of the excavation but it also offers an
additional protection measure so it protects the structure from sulphate
attack from the groundwater and hence is not considered as part of structural
thickness of the structure itself the primary lining also still fiber
reinforced and will be the same mix as the initial layer itself as our sole
purpose of water tight formation as I saw
water-type measure he uses still fibers to control the cracking in the temporary
condition so this is during the installation when bending is expected
and as mentioned it provides the only water tightness that we have as there’s
no traditional membrane in between the primary and secondary linings the
secondary lining itself has cast up against the primary lining as mentioned
before is reinforced with drum x5d fibers and some areas have rebar as well
and to be able to control the crack grips and limit the crack widths down to
less than 0.2 millimeters this is why they in place with the reinforcement and
this ensures the durability and promotes self-healing of the concrete as well in
order to have a watertight spray concrete lining the design is stipulated
a bespoke SCL mix which has a low cement ratio low water to cement ratio and a
low permeability a crystallization agent has also been put into the mix to help
enhance the mix as well there’s been a key focus on joints the joints with
details such that they’re 45 degrees there needs to be clean free from
contamination and stool fibres exposed as you’d expect from a good quality SEL
joint however to help with any poor workmanship or any any bad joints that
may be experienced we’ve also offered a more balanced and braces approach and
the sequence itself has been staggered so if you imagine a 400 mil thick lining
if you had one one place of water ingress that comes through that lining
only has to travel 400 millimetres the staggered approach allows that’s trouble
through two different areas and extends to water part of up to about one meter
which greatly reduces the chance of water ingress we watch through secretary measures and
high-risk areas such as around the base lab and around any junctions as well and
this includes re injectable tubes and water bars here you can see the key
requirements that as the designer ms es we have outlined for the watertight SC l
mix the sewer fibers require minimum tensile string for 1500 MPA the master
break concrete requires a low permeability coefficient of 1 times 10
to the minus 12 now let’s put that into context normal spray concrete has a
permeability coefficient of around about 1 times 10 to the minus 10 and up to
around about 1 times 10 to the minus 12 as well so we need to make sure that
we’re better than this and not just across the math spray concrete but also
at the joints as well within this very concrete the key addition here is the
crystallization agent and in this case we’ve used as I pecs
we recommend – of 5 kilograms per meter cubed and the way this crystallization
agent works is that it’s infused with the mix itself so it actually becomes
part of the mix and the reaction of any moisture that travels through the
concrete and by reacting the moisture and the byproducts of cement hydration
is able to form insoluble crisp insoluble crystals within like the
capillaries of the concrete which helps provide further ratio further assurance
of a watertight concrete the final mix that was used by B&B was developed in
conjunction with CPI and BASF and a lot of testing was under undertaken we now
have a look at the effect of adding this crystallization crystallization agent
had on the mix itself and you’ll see how it affected the early age strength
development and the plastic properties dysgraphia shows early age strength
development that was required we have the J plus plus curve which is a more
onerous curved and the standard j2 curve that’s used in spray concrete as it
requires a higher and earlier assurance gain and this was the curve that was
stipulated for use in the design as you can see with the addition of Zhai pecs
on our control sample over 7% accelerator it was not able to meet this
in the early set in the early hours on the workability as well when we added as
I pecs it reduced a retention time down from four hours to two hours or under
two hours in this circumstance this was not very reliable if we working with CPI
and BASF it was identified as I pecs was interfering with super plasticizer mr.
lay in the strength gain of the concrete once this was realized the super
plasticizer has changed and the accelerator has changed from SI 162 SI
194 as you can see with a new super plasticizer and the accelerator were
easily able to meet and exceed 2 J plus plus requirements and you’ll notice is
actually below accelerators Rock with only six point five percent the other
testing of 5.5% also exceeded this and that’s generally where we look to spread
between five point five and six point five percent the workability as well was
improved to a minimum of two hours and this was deemed adequate for the site
team here are series of photos from the trials taken in July 2017 a numerous
amount of tests were undertaken from about forty flexural beams and
twenty-five panels the concrete proved easy to spray with low levels of rebound
and good compaction this is regardless of location so such
as the invert the shoulders to mix proved to be very good and as you can
see for my cause and off lecture beams as well we managed to obtain a very good
mix there was a particular focus on the joints in joints so here on the left
hand side we’ve set up a panel the way we’d go about this is we spray the first
hand side and we try and form the food we would form the joint during the
spraying process after sprayed would come along with clean and tidy up the
joint with a high pressure jet wash similar to what we’d actually do in the
works we’d leave the sample for 24 hours after which would return and then spray
the rest of the panel once the panel was complete and cured for 28 days we’d come
back and we’d cost directly through the middle of the joint so we were able to
test this joint for compressive strength for more importantly permeability to
water penetration tests were undertaken on the mix the first one was a European
standard test which is specified in the works information this test the sample
for Phi for 72 hours under five bar the second test was a Morgan syndra
developed test it’s a far more ownerís test as it’s tested for nine to six
hours and at mbar of water pressure and it doesn’t just just measure the water
penetration but it also measures the amount of water left within the sample
as well and formulas were able to ascertain the water permeability
coefficient and as you can see on the screen this is a general setup of
testing equipment and what we’re trying to achieve on the right-hand side is
just very low penetration after six weeks of trials BB develops their final
mix they selected germ acts 4d fibers to be able to meet a minimum tensile
strength the permeability coefficient was a
minimum of seven times ten to the minus fourteen across both the mass very
concrete and the jointed samples which is much lower than our requirement and
the additional type X was still included as well the addition of his eye pics
eventually were managed to be able to satisfy the LA strength but it has
hindered to workability retention of the mix it’s also important to note at this
point as well that because of the addition of Zhai picks and the change of
the AB mixtures who experience the higher cost of your SEO mix of around
about sixty pound per meters cubed are now passed repaired those of you stood
at the back there are seats at the front so we’ll just take a couple of minutes
while laddies is getting ready for you to come down there’s more there’s plenty
of seats at the front so okay so the the pic top set works for
their shutting canon tunneling works commenced in the summer of 2017 and this
in itself was quite a puzzle to to solve given the proximity of these nearby
receptors the focus of this set up was to minimize the noise and nuisance
associated with the works initial ideas pointed towards the use of an acoustic
said which would be placed over the shaft cranium batching plant but given
the tight constraints at the DCO we were not possible to do that as you can see
from the image site bound you or given was a mere two meters away from the
extra dose of the shaft so this is the compromise safe setup we came to start
with concrete batching we initially considered the use of a traditional plan
given the tyre vailable working space this was not possible it was also not
seen as wise to have a group of bins that will own a day-to-day associated
with that due to the issues with the mix and the flow retention reduction ready
mix it also not be feasible additionally the code of construction
practice only love deliveries between 8 & 6 and we wanted to tunnel on a 24 hour
basis so the selected solution was provided by CPA euro mix and this was a
pre blended silo system this system worked by mixing all the dry
constituents off-site and kiln dried them and then the delivered to site in a
tanker and blown into the silo all that’s left to do on-site is dosed the
mixture with water and that’s done with a screw at the bottom of each silent we
went for four silos with a total capacity of 350 tons and this gave us
about a week’s supply the next point of interest is there lexicalized grain and
this cost an absolute fortune but as you can imagine it’s quite neat use of the
space thus of them being spun 30 meters over the shaft this was also a lot
quieter than a diesel crawler crane the runway for the crane was a real focus on
the design of that any metal to metal or metal concrete
components had rubber rubber pads on them to minimize the vibration the
runway was equipped with a number of flapjacks flapjacks so to enable the
team to take out any settlement as the shaft sinking internally works
progressed the last point worth noting is the muck bin design we went to went
for I’m following a number of quite high-profile near misses on Crossville
with precast L blocks we decided to go for a quite robust again expensive
kingpost Murray an alternative we saw this is best practice in a way of
reducing the risk you recovered from Peter the design required high focus on
quality SEL and this was very much in the back of our mind when planning the
works and we saw these free building blocks as key ways of driving that high
quality we needed to attract a highly skilled and experienced workforce we
needed to drive ownership between the gangs it’ll all be aware as many games
it’s always the gangs fault who’s not on shift we also wanted good levels of
Workforce morale we saw the best way to solve all three blocks was through the
proper selection of a shift pan you know actually thinking about that so here the shift buttons we went with
drops up shafts it part shift button very straightforward 10-hour shift
Monday to Friday no weekend working the tunnel shift pattern we went for a seven
a five to four free shift pattern with an 11 hour shift again no weekend
working the 11 hour shift didn’t comply with one of the key red lines of the
works information that been set out and that was a ten hour shift limit on
tunnel workers but through fatigue analysis we could show that actually
this had a lower fatigue or than a lot of the traditional shift patterns
7 27 27 3 where you work in 8 9 and 10 hours so dispensation was received however there’s a number of conditions
attached we have to provide regular questionnaires to the workforce
to gauge morale and fatigue and also provide fatigue awareness training for
all key members of the workforce shaft sinking took place early 2018 and we
were the first team untied way to start ACL Peter described the shaft earlier we
split it down into 29 advances of 1.2 meters the lining thickness changes as
we go down the shaft and we could only start that staggered joint detail that
Peter talked about from advanced 4 onwards excavation of the shaft that
always followed the same process but looking at the center advanced formation
using an 8 an excavator and then trimming the berm at one point 8 meter
deep burn back to profile the next stop step this was the key step in the whole
construction process joint preparation so there’s two stages to this stage one
inspect the joint and identify any poor SCL or overspray then if there was any
poor SLO overspray removed this with an excavator mounted rockwheel the second
stage we then jet wash the whole joint using high pressure jet washer quite a
lethal thing and this was my robot mounted so here’s what a good joint
looked like on the left you can see the six hundred mill stagger between the
death seal layers on the right 45-degree joint and five is exposed free of pull
material a point worth worth noting is one of the key hole points in RC ITP was
the inspection of these joints and every joint required sign-off by an engineer
with a minimum of five years sel experience application of SEL they
straightforward two layers with this continuously if possible to find a good
bond between the layers and then finally the levy ventures green cut before
starting the next excavation well all I see how works best practice from tight
and from across well joy was adopted this included our air fed our PE and
Bluetooth communication for any operative
any SEL restricted area in terms of testing we went above and beyond the
minimum works information requirements we needed a good quality SEL de and Dow
and that was absolutely critical for the design to do that we sat out a daily
workmanship panel and this was done at a frequency of one panel per nozzle Minh a
day so if two nozzle and spray the shaft advance would spray two panels these
panels would be called inspected for workmanship compaction voidage and
compressive strength it might seem over-the-top but even we
could identify any issues with the workers or the equipment within 24 to 48
hours it’s really critical so there’s a picture of the completed shaft and
totally took 15 weeks to complete we had an average advance rate of two point
before his poet over 1,000 meters cubed of SEL was sprayed in the process in
terms of settlement which Eve 19 millimeters or 19 point 1 millimeter
sorry enough prediction were 19 millimeters so I’m on target with that
moving on to the tunnel the tunnel was split up into one meter advances there’s
295 in total the face was excavated we using the ice ICT 120 had an excavator
and the 15 tons of spoil from each round was transported to pit bottom using a
series of track dumpers once a pit bottom it was lifted to the surface
using the Goliath grey like with all our tunnel headings on Tideway west the
laser show method was adopted that makes use of a remote profiling system called
the tunnel Beamer and also an inclined face as you can see on this exclusion
zone management plan our face was inclined to 20 degrees to the vertical
they significantly reduces the risk of injury associated with SEL fallout
this is adopted throughout Tideway West and I’m proud to say to this day we have
not asked one engineer or operative to work below freshly sprayed concrete
I think that’s a really strong point internal ground investigation was
undertaken using Pro grilling at 12 meter intervals with probe of 60 meters
ahead and what we found was consistent with this site investigation on this
image you can see a clear interface between London clay units be an API I
and that was denoted with a band of clay stone in the face the tunnel detail was
slightly different to the shaft given the constraints of its diameter and the
lining thickness so we were able to applaud adopter a large stagger but we
still had a stagger we had a hundred mil initial there and then a minimum of a
hundred mil stager between that and the prime ruler like the shaft we were
looking for the same drawing quality so 45 degree join fives expose to permitted
material removed the preparation of this joint took place in a similar manner any
poor material rock wheeled off of an high-pressure jet washed this is a bit
more challenging than the shaft so we found that the rock will often damages
that leading leading edge that initial and it be broken away shop great for the
tunnel was battling inside surface and pumped 350 meters to the face started by
applying the initial from the imager and working to the crown blowing that out of
an applying primer again invert the crown all in one operation
there is a real focus of the management of the dust during the invert section
this is an example of a man on the blowpipe blowing away a rebound from
that critical trailing edge however this is a challenge you’re very much reliant
on the skill of that man to ensure there’s no contamination of that joint challenges joint preparation aside the
tunnel advanced a good rate it took his 22 weeks to complete and we achieve an
average production rate of fourteen point one meters per week this Ray
actually meets the requirement we set out within the tender that was with a
seven-day week working shift pad so we’d reduce the number of gangs and
hours and we still make them at the target in terms of settlement on the
tunnel again we were broadly in line with the predictions read a maximum
settlement of 10 millimeters along the centerline okay so the interesting bit
post construction of their cell linings we undertook an ingress check so we
looked at both from the clauses not quite one liters per meter square today
and the second Clause is there any damp patches with visible movement of water
so I’ll start with the shaft surface area the shaft just over a thousand
square meters the allowable ingress per 24 hours was at 106 liters so that’s
what the works information would allow our actual ingression 24 hours 0 so the
second point number of visible joints with damp patches with visible movement
of water zero so following the completion of the shaft primary lining
completely compliant there was some ingress into the shaft though there were
two damp patches I’ll talk you through them now this is where we missed some
call hole repairs on the way down the shaft so we didn’t count that in the
analysis they will be repaired later but that does provide evidence that water is
loading shaft and it is watertight ok so moving on to the tunnel works
information allowed 434 liters of ingress for 24 hours we did our
measurements we had 9 liters in the hole 300 metres of the tunnel
however we came a bit under stuck on the second clause we did have a number of
damp spots we had 79 damp spots on the leading edge of the advances we’re not
talking about ruining water we’re talking about damp spots with a visible
sheen we found the second clause very hard to interpret
especially with decline the conclusion of that was we injected all those all
those damn sports so here’s an example of the typical locations of the damp
spots we observe and as I said earlier it’s extremely challenging to spray a
tunnel invert join without getting destruct in it and this is the evidence injection of those dumps boxes and taken
in accordance with be SEM 1504 and we use the type s swelling Mersey there you
have it after the injection we undertook another inspection following doing the
resin injections and the tunnel was signed office watertight okay so moving
on to the secondary line in construction this is one of the many elements of work
that worked at Hammersmith that was a project first and this was seen as very
much being a testbed for the tideway West in the whole of whole of Tideway
the design required a four-round shutter and we went to Colonel Technic miss
lavinia two deliveries of bespoke saw shutter just for these works this sure
takes onboard a lot of key learning from Lee t’l as Peter said the first one was
the shorter length that Lee will try pour concrete into a 30 meter long shot
here we’ve got a six metre long shot the maximum shot a landfill will adopt and
Tideway West is actually 10 meters so warm furtively turn off the second key
learning was designed the shut off a full hydrostatic head that means we can
fill it as quickly as we like the length and that feature together means you can
feel the shutter quick that significantly reduces the risk of cold
joint or voids or poor flow of concrete the shutter also incorporated a number
of key innovations the first one was the PLC automation and this is the first
tunnel shifter to have an integrated PLC so key components of the shutter were
fully controlled by that logic computer that enabled some key data collection
and also some new functionality so we could operate the shuttering
semi-automatic and automatic mode that gave us an extra safety net because it
meant we couldn’t damage the me machine I’ll give you an example when running
this in semi-automatic mode we could not drive the shortfall
with this food bars retracted we could not collapse the skin with the legs
retracted the final innovation was the use of automatic spud bars and again
they might look like normal spud bars but it takes away any manual movements
to lock and set these into position the key aim of this wood bars with a quick
setting and also for data collection prior to making the works the psych team
did some pretty comprehensive pretrial from the mixed development we started
off with free Ready Mix suppliers and whittled that down to one that makes was
then optimized for filling and vibration we wanted a good finish in the invert
that was one of the key issues at least at all to do that we had a bespoke
testing station again provided by kern and this made use of some of the forms
from the lee tunnel shutter as you can see the testing station was equipped
with a number of key features like the tunnel tunnel shutter it had the same
vibrators it had the same injection ports it had the same ceramic coating on
the forms the frame of the testing station enabled us to simulate not just
the invert which was done on retinol but also the knee and axis positions 10-12
panels were undertaken and with each panel we’ll try different consistencies
different filling methods so submerge Faline or top down filling and different
vibration settings so frequency I’m pattern and duration on the left you can
see the testing stations in use and the trials involved is simulating the tunnel
works so we batch the concrete delivered it to
site then pumped it 300 meters to the forms injected the forms and invite
their vibrator than is plant on the right you can see our form that’s been
struck once we’ve done this would inspect the surface of a blow hole
coverage depth or any of the defects and also take cause to validate compaction
and fiber distribution as you can see there’s some blow holes present and
that’s pretty common when you’ve got a fall around
shutter you’ve always got a top shutter effect and what you see there is
actually pretty good the panels enable is that outline what
good look like and this was all in a number of true they’re figure points
being set for the works so we had triggers on blowhole coverage depth and
diameter the delivery of the shutter took place in March this year and we
assembled 90% of it on the site surface five hundred and crane came in for the
lift it’s quite a tight one there was just
two hundred and fifty millimeters clearance between the ventilation
structure and the formwork as the Sai AP for that lift I was very relieved asked
for it dropped past at that point the show was loads bit bottom than the front
and rear portals was attached and then we tested all the spud bars all the
automation before driving at 300 meters to the end of the tunnel so that’s the
the shutter in situ the lining works when you take him with
a day shift and back shift shift pan watch a little split shift where they
overlapped and we were working 7:00 till 10:00 p.m. when planning the works
there’s a real focus on how we communicate between pit bottom pump man
and the lead liner obviously we did this with radios but we supplemented that
with a radio Vermont so the mine is a shutter could you stop the pump at any
point that was particularly useful when closing the poor as it eliminated the
risk of over filling the spud bars proved to be a sect that success they
were easy to set and quick the PLC enabled us to program a predetermined
pre low pressure so the spud bars would be extended that low divining to a
preload and we know the were firm in place also during pouring the sensors in
the spud bars enabled us to monitor the pressures
this is a useful tool and it enables us to see if there’s any differential
filling within the shutter finally we use the timber stop end and a quite a
robust one see 2014 Bills of 100 female thickness that this was required
to hold back the hydrostatic pressures particularly in the invert of the
formwork or the distribution system was done in steel and we started off by
using ten of the sixteen available injection ports
after a few pause we we identified that the concrete was performing well it was
self leveling and we reduce this to four ports the final filling sequence was the
pump submerge from the invar of the lattice level but then closed up all of
the two shoulders the thirty-five cubic meters of concrete required for each
pour took approximately two hours to to get by in the shutter so here are a few
pictures of the finished job after a sort of slow learning curve two to three
weeks of a poor every other day we were hitting our output and we achieved one
for 24 hours all the way through the tunnel we didn’t miss one pour as you
can see the finish is pretty exceptional and the the invert section you know they
exceeded expectations you’ll see from these pictures that the tunnel is
completely dry there’s no ingress at all so in terms of
water tightness requirements we’ve absolutely nailed it here okay I’ll hand
you back to Peter you will conclude our presentation we believe the words the hammersmith are
showing a potential of a water-type primary lining and we’ve done a small
comparison here against traditional waterproof membranes as well
each waterproof system has its own merits and we’re not taking that one
waterproof system is better than the other this is just another option to
consider for future projects the comparison does not take into
account any of the costs or trialing times that were undertaken before the
work started as you can see from what’s on the screen there is a potential of
saving the number of activities have been reduced the number of resources
required and the different interfaces have also been reduced not to mention
all the associated paperwork that goes with these and all the time that you
require for approvals as well in particular for Hammersmith what was
realized in terms of savings was a program saving mainly there was a small
cost saving as well associated with these works and in future with future
developments there’s a very strong possibility that this cost saver could
be increased further with the cost of the mix being reduced and with the link
for trialing as well or something further reduced as well especially now
as the president has been sets there’s potential that watertight spray concrete
lining can be used in future to move all the waterproof membrane was a BM B was a
joint BM BM SES innovation it was implemented in the early stages of
design development this utilized a bespoke spray concrete lining mix with
Xipe X which is to offer us a low permeability low permeability concrete
across bo for the massive body of the concrete and the joints this allowed the water
this allowed the primary line to be watertight and to work together with the
secondary lining in a combined manner the design of the philosophy was adopted
in the early stages to help simplify construction to reduce the cost of
construction despite that despite the extra cost of the mix itself reduce the
number of construction stages save time in terms of program offer the
flexibility that primary line in profile it can give you in terms of the SEL
reduce them out of material use in particular traditional reinforcements to
meet the durability requirements and to work with the limit amount of space that
was on on the site itself the shift pattern adopted by Hammersmith
proved to be a big success working weekdays only help minimise fatigue it
matched the production rates of the tender 24/7 pattern it’s sure that we
had a happy workforce and retained the workforce throughout the whole of the
construction of the primary learning and the secondary learning and overall it
drove good quality as well throughout the works the final finish of the tunnel
exceeded the expectations and this was achieved by the concrete testing carried
out prior to the construction and making minor adjustments along the way all of
the key learning that we’ve Orakei learning in the innovations that we’ve
learned how miss myth will be taken forward into the main tunnel on Thames
Tideway West as you’ve seen the prime lining of the shaft was completed with
100% water tightness without any additional work required due to more
difficult and naturally dusty environment of the tunnel itself some
leak injection was required to help bring it back within specification but
overall the watertight sel the high quality workmanship that we’ve achieved
has automated led to draw a tunnel at Hammersmith thank you oh what a fantastic job and a fantastic
presentation thank you I know there are a lot of SEL disciples in the room so
I’m expecting a lot of questions tonight so if there’s somebody sat on the floor
up there is that do you want to come down in front because you’ll be sat on
the floor for another half an hour thing no okay why we have a first question
please I’m good ah here we go so James in by engineering fantastic presentation
thanks guys it’s probably best prepared presentation and presented presentation
we’ve seen here for a long time so well done just wanted to ask why did the
tunnel and sharp need to be so dry yeah well this was Sal we’ve tied way because
if you could imagine if they had adopted the BTS specification for a sewer tunnel
they would have a lot been allowed a lot more water in there but if you imagine
all the tunnels on Tideway and all that ingress times 120 years that’s a lot of
extra pumping that you need to do abbey mills pumping station so it’s purely
driven by cost it’s nothing to deal with yeah just to reduce the cost of
maintenance of the whole scheme itself frontier can you wait for their Alex leave we
went on link so the XS he’ll mix did you test that against water pressures oh
yeah we did water penetration testing which is which are touched upon earlier
so we undertook trials before what we all took initial trials way before we
wanted to do with in works so we demonstrated this initial case study
first and as I mentioned we use two different water penetration tests to
demonstrate the effectiveness of this and then we further reinforce this by
more testing that being beyond the tip later on as well well the way the test
it works is um the sample itself is basically sealed on all sides and then
we drive a water pressure up uniformly across the bottom of the sample through
both mass poured concrete and jointed concrete and then we keep this pressure
there for nine to six hours where is consistent at 10 bar water pressure
throughout and then as I mentioned before from this were able to determine
the permeability coefficient because we could measure the depth of penetration
and the amount of water retained in the samples next to Willie yeah here we go hi John
from Vedic clothing and there’s not just a comment and other design I just have
some comments on innovations and because you’re learning philosophers are using
concrete the concrete area contact ok rid of the membrane basically due to
your full string the concrete you have very high wages amok and strain and also
due to the long-term consolidation you you’re not ready for so pretty clear
chrome 16 and across you will generate a beautician and you know that we all need
to like throw cracks these things we have seen when crossbow few occasions
and someone called upgrade and they probably think that well so for me I
mean your second line it was in grunt oh crap you dumb their weights concrete and
does not perform any functionality and the more problem just because you’re
young clay with the time develops your lining deformation will be bigger in the
bigger your even your funeral cracks in the crown and once it starts operation
the crowd was still regenerate and then you allowing water in cohesive water to
reach 2,000 lining for me it’s like it’s kind of mistake not if I so I hope these
kind of things probably the next time to be avoided thanks yeah yeah thank you
I mean the the primary lining is surfers designed to be watertight over the whole
duration of 120 years and it’s only expected really to deform in tension by
doing this installation so over there’s like over the lifetime once it’s been
installed or you’re gonna be getting its compression onto the primer lining so
you should get any more water ingress than what you already have at a moment
and the second design itself is designed purely for tension
well not pure attention but it’s designed for attention in terms of a
load a surge event another question yeah
Charles Allen it’s fun too Charles at the front well first of all congratulations for
creating the dried tunnel in London clay that’s not my question my question is
you showed you he showed a video of the modelling for the hydraulics and you
showed the vortex shaft the water drops raft tremendous amount of aeration of
the bottom of that that can create a problem called cavitation what’s being
done to mitigate against cavitation of the base in at the bottom of the shaft there’s the same if it’s just concrete
it’s gonna disappear within about two years yeah there’s a certain amount of
benching that’s been put in its place to help to help with this and as our judge
work judgment that we’ve been putting into the designed to help help allow for
this as well there’s nothing additional except for
the benching that’s been put in there to help provide moving off the water and to
make it self-cleaning as well okay we go we’ve we’ve handed over to the naughty
corner oh I’ve been a how much miss resident for 40 years and I’ve got to
congratulate you because I didn’t even notice you were there honestly really
nice siphoning very good but I just want to come you to confirm something it’s
not you that’s buggered up Hammersmith bridge is it it is him no okay I just I’m very pleased that you were
you with what you’ve done in that I’ve been arguing for 20 odd years that you
don’t need waterproofing in London clay yeah the one thing I did notice though
on your program you didn’t allow on your program the time it took you to do the
injection sealing at the end yeah which I think was a bit of catch-up beyond the
waterproof membrane right the injection was actually done concurrently with the
second okay so you do the first bit get the shuttering and then you take it off
the critical graph yeah I think it’s fair to say that with every
waterproofing system you use you have to do some injection anyway yeah you know
we’ve tried applying muster seal against so you do have to inject with all
methods in my opinion and the designer is happy with this composite lining idea
you see that really works well the design doesn’t rely on kompis action so
we’re relying on the primary lining to take who to the hometown loading so the
primary linings taking the long-term ground loading the second relying is
really taking the surge locally correct okay I’ll pay with that no Mike
McConnell is the pharmacy robbery yeah Mike and Carl retired ultra PD
congratulations guys the owner of detail in the actual testing and initiatives
and how you can do things better was excellent I think I’m left with the
memory here that you mentioned you want to transfer that onto the main board on
the western side of things but from a client’s point of view higher are all a
good value better practice points being picked up there that tied awake and then
try to introduce it in the other way in contracts yeah
we very much work as an alliance and Tideway and any issues any innovations
it’s just shared openly we’ve had issues at Hammersmith and they’ve already been
shared with West yes yeah even throughout the design stages
we have we held a transformational it’s a health and safety working group but we
also talk about design you know one of our key points was we’ve got an inclined
face and you guys you should try and adopt that as well if you if you can so
that is ongoing our next question and assembled you must
be bursting for a question there great torque thanks Judd million questions
just on the cavitation thing I was very interested in the vortex art involved in
Cara 30-plus years ago and at the bottom of the pot the drop shafts we had these
whacking great cast iron or st on sources that we cast in they worked well
five dollars each we put the other things in the bottom we do have a lot of
bench disks to help like material has been specified anyway about this system initially we
did have dead time but once we got into the swing of it the shifts were knocking
in five rings or six wings and we do actually have a gap we have we had
supervision throughout and so we always had a hand over it worked it took a few
weeks to get into it but by the end of it all getting fifty meters a week every
week Donald at the back don’t lament hyperbolic tanh safety dust
is one of the big health hazards of spray trunklid work he obviously did a
lot of testing and mixed design via short reads did you consider dust as a
major design parameter and if not why not well
rebound is was a mix design from I think we needed a maximum of 15% and we got 5%
but in terms of respiro ball dust we didn’t do any readings during the trials
I think one thing we should say is that the use of positive pressure fed RPE on
Tideway has gone a lot a lot further than we did on cross well we had air
flow helmets on cross her out but I remember the maintenance been the lead
minor banging his filter on the early math as we go down into the tunnel now
we have proper maintenance regimes in place to look after this equipment so I
think there’s been a real step change from from cross level to what we’ve what
we’ve achieved on pal day well dusters and natural by Potter’s is no of spirit
concrete linings and throughout the construction of the tunnel we
consistently down down as much as possible bloke blew out the dusts of
where possible we did pretty much as much as we could do really to try and
remove dust from the joint location I’m reversing my comment about naughty
corner now Roy you didn’t answer Donal second question there you’ve danced
around it anyway you blown away the dust that’s just putting it up into the
atmosphere the whole thing I’m not saying wasn’t as obvious on most of your
but in previous presentations she the one that’s been very obvious on the wall
on cross web especially excellent photographs but the mists that were
there from the reflection from the dust in the air and that’s Restaurant dust
you mentioned the helmets great if you maintain them did everything go anywhere
them did you wear one when you went down every engineer and operative in our
restricted area I love you if they were spraying yes but I generally go down
when they’re not spray yeah but that’s the whole point that the dust get that
is still there maybe not visible but it’s restful dust
yes and no precautions with anything so again you answered the question in there
and that’s the whole point where a very long discussion in another meeting here
earlier about this prior to this point with SEL the whole problem respirable
dust is usually not it you’re paying lip-service you give the guy on the on
the nozzle but the rest of the people you’re not and now you’re talking about
the dust that was affecting some of the joints and your answer was we cleaned
that by blowing it away it’s not a proper answer doctors sorry not a proper
solution to the problem not commenting on any any powders ceteris at frontier
you go you got a micro Thank You mighty thanks very nice presentation for it a
question for you were looking that perhaps the verification regime of
taking course he’s not very good isn’t is it something that you would like to
suggest to avoid in the future are you talking about the workmanship annulled
yes or taken course from the axle works well I think we have to take certain
amount of course from the works to ensure compliance in this instance it
was quite annoying as we wanted a water tight lining and we were drilling holes
in it but there was no way around that in the works information if there’s a
way to avoid you’d avoid the song time to just hear if there was a way to avoid
taking a course you would avoid yes we would yeah certainly to other
observations I’ve heard a lot about design the gentleman I think someone was
happy to discuss it to his downstairs because it would take some time the the
cavitation I think I think is is a real issue but as far as I remember this
feels very quickly isn’t the shaft so the cavitation you require to is more
pronounced where you don’t when this hits the bottom and then very quickly
this pizza do you want to discuss a divorce attorney this is another another
question but thank you very much for the presentation it was rated one more
question because we do have to Alan Scott from like a rock thanks for a
great presentation would you how confident would you be to use this
waterproofing system in soils granular soils with higher water pressures like
than with groups and channel 10 Assessors it all comes down to being
able to get good quality spray concrete so if you can’t get good quality it’s
very concrete and you can’t address the joints properly then you’re gonna leave
yourself exposed so it’s gonna be very difficult to use in you know Sands
ourselves I think we’ve got a bash on a little bit now I mean it was a fantastic
presentation really good a hell of a lot of detail in it and
think we should thank the speakers and I in our usual way please and now I’d like to invite Donald to the
stage who wants to say something else Thank You mr. chairman
good evening ladies and gentlemen right tonight I want to talk with buddy
standard six one six for safety and tunneling I could tell you that the
division of BS six one six four has been completed and the document will be
published sometime late in October however tonight and here for a different
reason I want to recognize the contribution which one of the members of
six one six four committee has made over the past 35 years of soul
he’s been heavily involved in four revisions of the standard they send out
text for comment he’s always amongst first to respond sometimes he responds
before even asked for comment in the latest revision as in the others he is
worked on and been responsible for many of the changes and the sections to deal
with plant and equipment this British Standards institution distinguished
service certificate and I’m very pleased to ask Peter ended to come up and
receive the certificate for all the work he’s done on bs6 164 over three a half
decades well done Peter so from the young turks
to the elder statesman there so we have the chair slide snap please so we’ve
been promising an evening out of London for some time and here it is Tuesday the
15th of October 2019 5:30 in Newcastle subject will be building damage and Bond
Street Station building damage assessment BTS will be providing buffet
and drinks afterwards and for those of you who want to rod young will be
provided providing a guided tour of the clubs of Newcastle after that so it’s up
to you which which part of the menu you want to select but please if you’re in
that area please go up and enjoy the night next please so as you know we’re coming up to our
fiftieth anniversary and we’re putting a call out for sponsorship there are there
was an email sent out two days ago I believe for sponsorship for corporate
members and individual members we’ve already had a number of positive
responses I think we’ve had three corporate members coming forward already
offering sponsorship and more impressively a number of individual
members coming forward and offering sponsorship as well so if you’ve got any
questions on sponsorship see Annie – woo in the bar next please call for content
in the book we have today put aside a budget for the
publisher we’ve got a lot of stories we’ve got a lot of raw material looking
at you all in here tonight there’s a whole load more to harvest so if you
have a story to tell amusing or otherwise see John Corcoran
or Ken spy be at the bar next please we’ve opened up bookings for health and
safety course to be run at the end of November the prices opened up I think on
Monday prices are 155 pounds for members 190 pounds for non-members I think had
you spend more than 155 pounds on your shoes days this is a two two day course
for a hundred and fifty five pounds and it is filling up fast so if you want if
you if you want to save on the shoes and go on the course this is it next please
now Anita has given me a lot of words to read out here so if you’ll bear with me
I’m going to read them out she says however would you mind reading a longer
bit please the BTS are now incorporating data from the transforming tunneling
safety group TTS G onto our website TTS G aim to drive a step change in
tunneling safety Health and Welfare one route identified as contributing to this
is that we must as an industry improve the way we learn from our experience so
very much touching on on the questions asked tonight therefore we have opened a
portal for the sharing of good practice and lessons learned on the TTS web page
you can find safety videos health safety and welfare lessons learned
good practice guides good practice proposals TTS G would like
more contents on the website with your contributions today we’ve had
contributions from Vaughn C construction Balfour Beatty Morgan sindelle and
Tideway so please more contributions if you have them if you have any
information that you want to share please contact Nick Butler and Nick
Butler Nick Butler’s email is their quite simple to remember Nick Butler at
mock next please so moving on to our calendar
looking forward our next meeting is on the 17th of October and it’s going to be
all about drift filled hollows pingos I think so or on London clay next please
and that that’s a geological section I think of what is that a Pingo John is it
yeah that there’s a Pingo I’m not sure what the other picture is but I’m moving
on from that please on the 14th of November you all remember that this is
the anniversary of the Channel Tunnel opening and we’ve invited Bruno Kampf of
week across to give the Harding memorial lecture and we have recently certainly
been market leaders in terms of innovation in TBM tunnelling so this is
so this is another good reason to come on Thursday the 14th of November and I
think who knows what next please Bruno’s put in a couple of pictures of the
innovation and tinman using a TBM for cross passage and construction next
please right firstly I would like to thank Mike
McConnell for his sterling attempts at bringing the institution of civil
engineers to heal on refusing to service with sausage and chips and pasty and
chips Mike taking up his shillelagh and
certainly gave the responsible director a battering that he will remember for
some time the good news is that the institution of civil engineers are
bringing back sausage and chips and pasty and chips but not tonight the bad
news is that they’re putting the price up to four pounds seventy three four
four either and the good news is that they’ll be provided well maybe maybe not
they’ll be providing baked beans as well as the sauces and chairs but the the
tunneling society of of today decided to take the risk on numbers the at the IC e
were concerned about the numbers taking up the the meal we have offered to take
the risk on numbers so please do call in next month for your sausage and chips
and we do we do have a plan to look at sponsorship of the sausage and chips as
well as the bar so that price might come down right next Lee’s right I think it’s
fantastic to see so many of you here tonight had in his part of presentation
a testament as a highly skilled and experienced workforce and supervision
involved in the construction of tunneling and it’s so good to see so
many supervisors here tonight we we engineer’s find a hundred and one ways
of not doing something leaving the foreman to find the one way of doing it
I’m so pleased those of you who are supervising please come along in future
you are the backbone of our industry and more than welcome a on on a Thursday
evening or any other activity of the tunneling society now the good news for
all of you is that the bar is sponsored tonight by CPI and Morgan symbol
engineering solutions so that was a spontaneous applause for both his
sponsors and without further ado the bar is open thank you

BTS Lecture Thames Tideway West The Design and Construction of Hammersmith Connection tunnel
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