Meeting No. 3 : Scope - Studies for HL-LHC Civil Engineering

Celine BellengerYung LooClaire WilsonMatt SykesDr David Hiller

19/03/2015

Scope of work

Proposal 1Task 1: Roadheader Vibration Support

Task 2: LHC displacement predictions from Hi-Lumi tunnelling

Output: Summary technical note

Proposal 2Task: Baseline toolbox of typical construction activity and low excavation vibration methods

Output: Summary technical note

+ Meeting at CERN to present main findings

Out of scope – Vibration testing support

No realistic alternative to improve current prediction/approximation without conducting some site trials and measuring with specialist instruments that give the full range of vibration that is of interest

Test measurements necessary and mandatory to understand and investigation of the profile of vibrations across the affected length of the LHC

Vibration testing support has been removed from the offers (no site trials)

Some readjustment/recalibration will be needed in all cases: to be planned

Scope of work – Task 2: LHC displacement

Task 2: LHC displacement predictions from Hi-Lumi tunnelling Analysis to calculate the instantaneous ground movements on the LHC from the

HL-LHC tunnelling works, at Point 5. Ascertain relevant geotechnical data (case studies, sensitivity analysis) Results in 3 directions (3D ground movement modelling) to determine potential tunnel induced ground movements and associated sensitivity analyses.

Nota 1: need to know understand tolerable limits along the LHC Nota 2: potential long term movements not considered

Scope of work – Task 2: LHC displacement

Scope of work – Task 2: LHC displacement

12m outer diameter shaft

Proposed High Luminosity LHC tunnel

Existing LHC tunnel modelled as displacement lines

Scope of work – Task 1: Roadheader data

Task 1: Roadheader Vibration Support Investigate roadheader suppliers Case studies Potential vibrations and impacts on the LHC from the HL-LHC tunnelling works Nota: need to know understand tolerable limits along the LHC.

PPV = 2* π * f *AWith PPV = Zero-to-Peak, or Peak Particle Velocity (Units: m/sec, mm/sec)

f = Frequency (Units: Hertz)A = Zero-to-Peak, or Peak Displacement (Units: m, mm)

i.e. for 1 μm:

Frequency Amplitude PPV

Hz μm mm/s

50 0.6 0.19

50 1 0.31

100 1 0.63

150 1 0.94

200 1 1.26

Scope of work – Task 1: Roadheader data

Suppliers contacted for roadheader vibration data:

• Sandvik:• Some information available on vibration (see following slide)• Lowest values in the 0.01mm/s range at 40m distance, or just

below

• Herrenknecht:• Do not manufacture roadheader (only roadheader booms for

some open face tunnelling machines)• No published information on vibration available, even for TBM

• Eickhoff Bochum : • Do not manufacture roadheader anymore (second handed

roadheader on the market)• No vibration data

Scope of work – Task 1: Roadheader data

Further information from Sandvik:

• Vibration measurements only from heavy duty roadheader series MT720

• Ground conditions, physical properties of the material and influencing parameters like acoustic impedence, reflection etc make it difficult to compare roadheader applications

• Roadheader max frequency 80Hz, mean 40-70Hz – in agreement with Dr Hiller

• “Vibration intensities at a Roadheader application are pretty low compared to a D&B operation and even approx. 30-35m behind the operating face we were not able to differ between Roadheader induced vibrations and background noise!”

• More detailed project information on 4no. projects – geophones within the tunnel behind the face and in boreholes adjacent to tunnel

Scope of work – Task 1: Roadheader data

Suppliers contacted for roadheader vibration data:

• Erkat:• Work only with drum cutters • According to their experience on several jobsites the vibration

level will be below 0,03 mm/s.

Roadheader

Drill and BlastProject Sonnenburg in North-Italy

Rock : Quarz Phylites (UCS 70-170 MPa)

0.03

Scope of work – Task 1: Roadheader data

Suppliers contacted for roadheader vibration data:

• CSM-Bessac:• Do not manufacture roadheader (open face with drum cutter)• Experience on molasses: Saint Genis Pouilly France-Switzerland

+ Toulouse metro • No information available on vibration

• Alpine:• No answer at the moment

• MSB-IBS (Schmitt Gruppe): • No answer at the moment

Scope of work – Task 3: Alternative construction methods

Task 3: Construction baseline toolbox Establish a vibration baseline including roadheader, hydraulic breaker, percussive

drilling, coring Investigate low vibration excavation method/impact including expanding

demolition agent, hydraulic fracturing

Nota: limits will be the data we can collect.

Scope of work – Task 3: Alternative construction methods

Source: Report for West Connection Bridge project, Washington state

PPV in in/sec at 100 ft (30 m)1 inch=25.4 mm

0.08 mm/s

0.08 mm/s0.15 mm/s

19 mm/s0.28 mm/s

Preliminary findings

Compared to 0.01-0.03mm/s for roadheader

Scope of work – Task 3: Alternative construction methodsExpanding demolition agent - 2 Suppliers contacted:• Ecobust

• Used in Xstrata Mines in a narrow tunnel• Waiting for more information

• Dexpan• Used with mine, but confidential

information

No Vibration, except for the drilling partDifferent product depending on ground temperatureUp to 170 MPa rock strengthLimitations: size and depth of the holes (1.5’’ to 2’’ diameter = 3.8 cm to 5cm and 5’’=13 cm depth)

• Arup has done research for a Sensitive structural project (Australia) • Key is to provide as much free space for the

rock to crack into by using burn holes

Any Questions?

Next step :- Consolidate what we have on vibration- Analyse 3D displacements

16

Backup Slides

17

•Mechanical Excavation- 30-80Hz Region dominates- Tails off to 200Hz

Re-cap: Post-Meeting no.1

•45m away, PPV ~ 2x10-4 m/s, 50Hz- = zero-to-peak displacement of 6x10^-7m (0.6μm) [comparable to 1μm limit?]

2-3% of the max at 200Hz

Re-cap: Post-Meeting no.2

• Sandvik data as a comparison – lowest values they have presented are in the 0.01mm/s range at 40m distance, or just below – therefore they are capable of reaching the same order of magnitude of vibration as suggested and achieved in the presented past projects.

• But is this within tolerable physics machine limits?

• Possibilities for mitigation are small to none

“Mitigation options for mechanized tunnelling activities are limited. In some circumstances, it might be possible to limit working hours” - British Standard

• Possibility to engage with Sandvik with further detailed geotech parameters and vibration criteria to understand in more detail possibilities and limitations

• Identified conventional vibration limits of existing roadheader machines. Need to understand if these are tolerable, and physics requirements can be compatible at these limits.

Case Study - Roadheader Vibrations

Project Location Geology

Lowest predicted ground borne noise vibration criteria

PPV (where possible at a distance ~40m)

Range of ground borne

noise vibration

recorded PPV

CommentsAny project guidance on

sensitive structures/equipment

Brisbane Airport Link,

2006 1

Brisbane, Australia

Rock (limited info)

0.01mm/s at 40m distance

n/aFocus on

damage/human comfort in buildings

Typical satisfactory vibration levels for sensitive buildings –

Maximum 0.5mm/s

Brisbane Airport Link,

changed project, 2008 2

Brisbane, Australia

Rock (limited info)

0.01mm/s n/aFocus on

damage/human comfort in buildings

n/a

BaT project 3 Brisbane, Australia

Rock (limited info)

0.08mm/s at ~35m distance

n/aFocus on

damage/human comfort in buildings

Sensitive structures identified

Linking Melbourne East-

West Link 4

Melbourne, Australia

Basalt and siltstone

0.15mm/s at 40m distance

n/aFocus on

damage/human comfort in buildings

Typical satisfactory vibration levels for sensitive buildings –

Maximum 0.5mm/s

Sensitive structural project 5

AustraliaWeak rock (sandstone)

0.2 mm/s

0.05-0.8mm/s (0.05mm/s measured at

~30m distance)

Safely within vibration criteria for “sensitive

structure”

Road header successfully used in close proximity to sensitive

structural elements

Northern Link 6 Brisbane, Australia

Rock (limited info)

Threshold was assessed as that of human perception

~0.15mm/s

0.02-0.26mm/s (no distance information)

Focus on damage/human

comfort in buildings

Typical satisfactory vibration levels for sensitive buildings –

Maximum 0.5mm/s

Table summarising the vibration levels for different projects, specifically using a road header

Sandvik MT720 – Montreal, Canada (135Tonne)

Data from SandvikShale and limestone

Sandvik ATM105 – Pozzano, Italy (135Tonne)

Data from SandvikNo geology information

Vibration data classified according to geology