In person (Western Australia) and webinar

Speaker:

Alvin Francis has 11 years of tunnelling experience working on a wide range of tunnel projects in challenging geology, from Berapit Twin Tunnels- Electrified Double Track Project (Malaysia), Klang Valley MRT (Malaysia)- where the world’s first Variable Density TBMs specifically designed to handle the complex limestone karst zones were deployed, North-South Transmission Cable Tunnel- 60m in depth in extremely hard Bukit Timah Granite (GI- GIII) (Singapore) and the Thomson Line tunnels T207 (Singapore).

Alvin has been engaged as the Project Engineer for Tunnels, on the Forrestfield Airport Link since 2017 and has completed the twin 6.7m diameter 7.5 Km Tunnel excavation works across 5 different geological strata with difficult & variable properties – alluvial sands to soft rock (2-4 MPa Sandy Siltstone/Claystone) using the Variable Density TBMs while tunnelling under the fully operational Perth Airport runways, taxiways and aprons, roads & local Railway Lines. Following the completion of Tunnelling and an unexpected incident at the Dundas Road Cross Passage, he then worked on the Dundas Road tunnel reinstatement.

Talk Outline:

On 22 September 2018 a leak developed during construction of the first tunnel cross passage, Cross Passage Dundas, into Tunnel One, approximately 200m north of the Forrestfield Station site and the launching point for the TBMs. As a result, water and silt entered rapidly into the tunnel at up to 60L/sec resulting in loss of ground around the tunnel and subsequently leading to the formation of a sinkhole at the surface alongside and partly beneath Dundas Road. The groundwater pressure, and the associated lack of support to the tunnel lining, caused permanent localised distortion to the tunnel shape and movement of the segments which make up the tunnel lining, ultimately damaging a 26m-long section of Tunnel One (16 rings). This talk will briefly describe the setting, the incident and then outline the technical solutions developed to enable reinstatement of the tunnel lining to achieve operational clearance and a 120-year design life using spheroidal graphite iron segmental lining (SGI).

Teams link: Register for the Dundas Road tunnel incident webinar

At 5:30 pm, finger food, beer, wine and soft drinks will be provided, for an informal pre-talk get together at the venue. Come and meet your fellow professionals who are interested in tunnelling. The technical session will commence at 6 pm and run until approximately 7.00 pm. Dinner afterwards will be coordinated with the speaker at a nearby restaurant (pay your own way).