All posts by Gary Buck

No thuds after 10pm tonight

Good afternoon everyone,

I’ve spoken to, or emailed many of you yesterday about the works going on some 20m underground in front of the Botanica.


I thought I’d provide an update on progress, and the plan for works going forward.

Progress last night was not as good as expected as one of the excavators broke down in front of the excavation work face. As you can imagine this significantly slowed process and has caused a re-think from the program that I outlined to many of you yesterday.

Works will continue this afternoon once the excavator is repaired, but will stop at 10pm.

There will be some sections of the blinding that will need to come down during these works, as you’d be well aware these blinding sections have been causing the vibration as they hit the ground.

I’ve included a photo below to show the remaining works. You can see in the photo the smooth ceiling sections and the rougher sections around it. The rougher sections is where the blinding has yet to come down. For orientation, the corner you can see in the far right of the picture is in front of the Botanica at the Bowen Crescent end. The curtain at the end of the tunnel is the end of the station box.

The team will start works this afternoon focusing on the western tunnel closest to the Botanica, then into the evening they will move to the section furthest from the building to help reduce the vibration.

On Saturday morning we will resume during normal working hours, starting at 7am and work through until 1pm.

The program from here will become clearer once we see how much has been completed on Saturday.

For those who are interested, the critical interface in these works is the electrical connections into the tunnel. these connections power everything in the tunnel between Anzac Station and the Eastern Portal, including the lighting and cross passage works. The excavation can’t move forward until this power is disconnected and removed and once the excavation is complete, power needs to be reconnected as quickly as possible. With last night’s delay these disconnection works will happen early next week.

My apologies again for the disruption during these works, as always, If you’ve got any concerns, don’t hesitate to get in touch.

I’ll provide a further update on Monday.

Thanks, Rob

More on the crashing noise

I know it has been really bad – I have been talking to CYP.

Seems that it was not the concrete rings but the ‘blinding layer’. Let me try and explain.

Deep underground they have a dirt surface. They lay a ‘blinding layer’ of concrete. On top of that they lay the steel reo and then the thick layer of concrete that becomes the floor of the concourse.

Once all that thick concrete layer is cured and secured to the walls, they dig underneath it all – that is all the dirt you see coming out. Once they have dug underneath they need to remove that blinding layer, it is just a working layer. It is concrete and they let it fall.

The big thuds are big chunks of concrete falling. I have asked if they can do in smaller chunks and not after 10pm…not sure that they understand the impact.

Several people have asked about building damage, this is the CYP reply (the thud at 930am today was 2.8mm/s)

The limit for the project for structural damage is 5mm/sec with our warning being 3mm/sec. We hit just under 2.5mm/sec, so whilst it was a big thud – it’s very unlikely to cause damage to any buildings.

James has included a bit of commentary of what levels of vibration mean:

~ 5.0 mm/sec Damage to very sensitive buildings may start to occur

~ 4.0 mm/sec and above – scary.  Very concerning.  Uninhabitable if exposed to vibration for long periods

~ 2.0 mm/sec RMS (2.8~3 mm/sec PPV) very annoying, concerned

~ 1.0 mm/sec RMS (1.4 – 2 mm/sec PPV) very clearly perceptible, annoying

~ 0.4 mm/sec RMS (~0.5 mm/sec PPV) clearly perceptible, potentially annoying during the daytime

~ 0.2 mm/sec RMS (0.28~0.3 mm/sec PPV) perceptible, potentially annoying during the night-time in sleeping areas

~ 0.14 mm/sec RMS (~0.2 mm/sec PPV) just perceptible

~ 0.1 mm/sec (0.14~0.2 mm/sec PPV) threshold of perception

< 0.1 mm/sec RMS (0.14~0.2 mm/sec PPV) not perceptible

More on Saturday access

There will be traffic management and they will allow access for delivery people / intercom access. Obviously if they are in the process of lifting then the delivery person may have to wait 10 minutes type time period.

Bottom line is that there will be a human on duty and you can talk to them if any issues.

That loud crashing noise was CYP

A number of you have commented to me that there was an almighty crash at about 845 pm tonight. Seemed so close it seemed to be inside the building.

CYP have admitted they dropped this large concrete ring onto a hard surface at that time. It is right in front of our building. They are supposed to place some soft soil underneath….but clearly didn’t.

Bad news is that there is still another coming off tonight…hopefully they get their process right this time

Feel free to call 1800 105 105 if you want to comment directly.

Next few months – CRG update

Public comments on Station and surrounds

Will occur around Q3 this year is my best guess so maintain that rage for another few months!!

Tunnelling

Complete at last – the vibration should be over.

They are now removing rubble and sacrificial tunnel material plus constructing the cross passages. These are emergency escape routes between the two tunnels.

Much of the gear at Edmund Herring Oval will now be removed. Most gone by end of August EXCEPT the power station. The oval will now be used as a set down area – ironically at the public hearing all those years ago, it was to be only used for setdown

Other info

The actual steel rail to be used in the entire tunnel from South Yarra to CBD (through the Domain Station) will be pulled in from South Yarra. This is great news for us as it means we won’t have massive volumes of rail deliveries during the night!!