civil tech forum - developments near rail tunnels 2015- civil forum – october 2015 asset standards...

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Civil Forum – October 2015 Asset Standards Authority

Developments near rail tunnels Sarath Fernando Principal Engineer Geotech

April 2015ASA Technical Forum; Civil October 2015

Developments near tunnels T HR CI 12051 ST

• Background • Scope of the standard • Content • Questions/ suggestions/ comments

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ASA Technical Forum; Civil October 2015

Existing tunnels

• City circle tunnel • Eastern Suburb Railway

tunnel (ESR)

City underground rail system

• Wolli creek to Central Airport link tunnel

Epping to Chatswood tunnel

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Existing tunnels

INSIDE SYDNEY'S TUNNEL SYSTEM The current system in use, showing Dr Bradfield's proposed lines

ASA Technical Forum; Civil October 2015 -

Existing tunnels

EASTERN SUBURBS RAILWAY- SHOWING INTERCONNECTION WITH ~ EXISTING CITY RAILWAY SYSTEM ~

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Tun11els NOT tn v'st

Saa. s · 1


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Issues related to assessing developments near rail tunnels

• lack of clarity/information on rail easement, protection zones etc. (old tunnels)

• lack of information on existing tunnels (construction, WAE drawings, supports etc.)

• lack of technical guidance/requirements for developments • past projects as a justification for new approvals

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Scope of the new standard

To provide technical requirements & guidance

• In the initial stage of the development

• Require tunneling expertise

• Review of existing documents/guidance etc.

• Industry consultation

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Existing documents/guidance

Regulation

Guidance

Technical standards ??


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Regulation

Legislative requirements

• State Environmental Planning Policy (Infrastructure) 2007 - Reg 86

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Regulation

Legislative requirements

• Transport Administration Act 1998 provides statutory protections in respect of underground rail facilities

These protections include a right of support and an implied covenant for protection of underground rail facilities over land above, under or adjacent to the subsurface stratum. The relevant rail authority also has a right to claim compensation from a person who, without consent, carries out an activity, which damages or interferes with any underground rail facility.

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Existing guidance documents

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TfNSW documents/requirements:

• ECRL underground infrastructure protection guidelines: 2008

• Guidelines for development within vicinity of the Airport line: rail Access Corporation: 2000

• Brief for review of geotechnical & structural design for development adjacent to or above rail (RailCorp)

• T HR CI 12080 ST – External development

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The Rail Corridor Management Group ("RCMG") is the workgroup interfacing with “Sydney Trains” that will coordinate and manage the review and acceptance of requests from Applicants.

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Home > About us > Transport agencies > RailCorp > Building near the ra ilway

Building near the railway

Working in and around the rail corridor by non-rail organisations

If you are outside the rai l industry and want to work in or near the ra il corridor, the sections below describe how to get s tarted and contact us so we can help you design, plan and carry out your work safely, and w ithout effecting ra il operations.

Getting started

Read, complete and submit the information and application package along with a cheque addressed to Sydney Tra ins Rail Corridor Management Group Application Fee. The application fee w ill be determined by Sydney Tra ins.

Transport RailCorp

Once the application fee is received a prel im inary desktop review wi ll be undertaken with advice con firming the steps to further progress.

You may also refer to the Transport Standards web page for information relating to all Transport and Sydney Tra ins standards. Please note: Rai l Corp standards are sti ll active and apply in some ci rcumstances, however for any enquiries please contact the Asset Standards Authority (ASA) fo r advice.

Please note that entering railway property or interfering with rail assets including gates and fences without permission is an offence.

Contact us

Rail Corridor Management Group Level 2, 36-46 George St Burwood, NSW 2134

For enquiries, please refer to the map of rail corridor responsibili ty z.ones and contact the relevant Interface Manager who can provide feedback and fu rther directions.

Tags: NSW Tra ins, Sydney Trains, Trains

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typical causes that could affect tunnels

• loading from development • ground deformation resulting from excavations and

external loading • induced vibrations during construction and operation • ground-borne noise impacts • electrolysis • discharge of stormwater from development • ground water leakages into tunnel • loss of support to any underground rail facility • temporary structures • direction of stressing of anchors

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1). Tunnel protection zones & restricted activities ??

Proposed content (technical requirements only)

e.g. ECRL tunnel

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e.g. Airport link tunnel

Allowab.e rooling loa<ls

6 MPa

HAWKcSBURY SANDSTONE

1.5m min:mum clearance 'or piles from any tunnel.

D NOT TO SC.ALE

150 KPa m(;ximum imp:ised load above the tunnel.

() I 0 • ·;: E

~I() 0 x 0 0 ,. .... fi 0.

6MPa

am minimum grourd cover.

Emersency access tunnel.

Rail level ~o -~~o

....................... ~ Al foundation and construdbn proposals are to be certned by a suitably quc.lified and e~penenced tunne ling engineer on a case by case basiS.

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e.g. Airport link tunnel

Foundation loads are to be transferred past the tunnel when the applied pressure on the tunnel lining would exceed 30KPa.

All foundation design and construction proposals are to be certified by a suitably qualified and experienced tunnelling engineer on a case by case basis.

Load transferred past tunnel

Bridging slab

': ·.·. •.· ....... \ :• ..... ....... ·. · .... •.· .. ·.:• ..... .. : " ... ·.· .. •.· .. · ... •.· .. ••· .. ·.· .. ·.: • ... •• : ·· ... .......... ·.+ ..

Isolation of slab from ground

© Mnhnum clearnnoe of 2m ' '"" or 3 x the pile diameter to the pile centreline whichever is greater.

I • 10.4m external diameter

Load transferred past tunnel

·® 10m minimum cover over tunnel (to retai11 stability of the segmental concrete lining and to counter buoyancy effects)

NOTTO SCALE

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City circle tunnels

• No defined protection zones similar to ECRL tunnels

Min rock cover ??

Min clearance ??

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City circle tunnels

• No defined protection zones similar to ECRL tunnels

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Asset Standards Authority Purpose, priorities and progress | 24ASA Technical Forum; Civil October 2015

2). Restricted activities within protection zones

Example:

First Reserve, inside SupportZone

First Reserve, outside Support Zone

Excavations for basements, footings Not Allowed 1. Excavations less than 2.0m depth, assessment not required.

2. Excavations greater than 2.0m depth, assessment required.

Shallow footings or pile foundations Not Allowed Allowed subject to load restrictions. Assessment required.

Tunnels and underground excavations

Not Allowed Allowed. Restrictions apply for excavations below the existing tunnels. Assessment required.

Ground anchors Not Allowed Allowed. Assessment required*.

Demolition of existing subsurface structures

Not Allowed Allowed. Assessment required.

Penetrative subsurface investigations

Not Allowed Allowed. Assessment required.

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3). Survey information

• Detailed plan shall be prepared to determine the location of the site in relation to existing rail infrastructure

• Survey should identify: boundaries of the development easements & encumbrances location of rail tunnels location of rail corridors under rail expansion program • Proponent should undertake service search to identify

location of services to ensure the clearance requirements for any underground cables etc. are met.

4). Permissible loads

• Vertical loading • Lateral loading • Uplift

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5). Cracking

• no new cracking • existing cracks not to increase more than 0.5 mm in width • existing cracks length not to increase more than 2 mm • unfavourable crack patterns to be repaired before work ??

6). Noise & vibration

• vibration limits during construction • limits during operation • vibration isolation

7). Ground anchors

• restriction to protection zones • impact shall be assessed including impact of their constn. mtd.

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8). Engineering assessment

a). Geotechnical investigation

• Existing in-situ stresses in soils & rock mass (lock-up stresses etc.) • Critical geological features such as joints, bedding planes, dykes etc. • Rock & soil properties • Existing ground water regime

Geotechnical investigation could comprise of;

• Drilling boreholes • Geophysical exploration • In-situ tests • Geological mapping

Locations of ground penetration shall be verified by the project surveyor & approved by the rail authority.

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Construction drill came from site above rail tunnel 0 27 March 2013 London

Sections of a drill which broke through the roof of a rail tunnel came from a construction site above the ground, accident investigators have found.

Staff spotted two broken parts near Old Street Station. east London. on 8 March after a passenger train driver reported water pouring on to the train's roof .

The metal drill parts. 2m (6 5ft) in length , were on the tracks .

Rail services on the busy F irst Capital Connect route were suspended for about three days as repairs were carri ed out.

A driver on the passenger train travelling from Moorgate to Welwyn Garden C ity reported muddy water pouring on to his train's roof near the station .


Engineering assessment

• 2D/3D modelling • Predicted displacements • Predicted incremental stresses • Sensitivity analysis • Impact of construction method

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11). Temporary works

• Any temporary components of shoring systems that potentially affect the railway tunnel shall have a minimum service life of 10 years

• Any support from the permanent structure shall be excluded • Temporary dewatering shall not have any affect to existing tunnels

12). Stray cu rrents & electrolysis

Potential effects of stray currents and electrolysis in the electrified area of the rail tunnel shall be considered

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13). Drainage

• Impact of changes to ground water regime • Dewatering works • Installation of barrier's to ground water • No damage to waterproofing of tunnels

14). Dilapidation survey

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15). Monitoring plan

Developer shall implement a comprehensive monitoring system that may comprises of an early warning criteria in agreement with rail authority.

Monitoring shall verify the predictions made at the design stage wrt displacements, stresses levels, vibration etc. in the tunnel and critical infrastructure.

Developer’s geotechnical consultant shall assess the monitoring results continually and assure the safety of tunnels to rail authority.

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Typical monitoring may comprise of;

• Borehole inclinometers for ground displacements • Piezometers for ground water levels • Tunnel convergence/divergence monitoring • Rod extensometers for ground subsidence, lining sag • Crack meters, tell tales for crack monitoring • EL beam sensors for differential movements and rotation • Tilt meters • Stress/strain gauges for stress monitoring • Survey monitoring • Vibration monitoring

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16). Demolition works

Demolition works shall be planned and carried out such that no damage to existing rail infrastructure or rail operations.

Vibrations to the existing infrastructure shall not exceed the set limits. Vibration monitoring shall be carried out as required.

Hydraulic rock hammers shall not be used within 5m of any rail tunnel.

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Thank you

Questions/suggestions/comments ??

civil tech forum - developments near rail tunnels 2015- civil forum – october 2015 asset standards...

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