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
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
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