A quick site update. Things were quiet with the sheet piling team at first, then suddenly everything ramped up.
What happened after the testing
Earlier, the geotechnical engineer certified the platform for 250 kPa bearing capacity, and nuclear density testing (a quick on-site test of how tightly the ground is compacted) backed that up.
We received results of:
- 95% on one test site
- 97% on the other
The geotech report required results above 93% (measured against the material's maximum dry density, the tightest the material can be packed in a lab test), so we comfortably met the threshold.
Heavy rain—and a new certification
We finished the testing last week. Then we had 4 to 5 days of serious rain that flooded the site. The ground was still extremely hard, but water softens compacted fill and can wash out fines, so after a rain event the engineer has to reissue the certificate to confirm the platform is still good.
Today’s work: recertification + drainage upgrades
The geotechnical engineer came back this morning and re-certified the platform after the rain. The sheet piling company needs that certificate before they can set up on site.
We also brought in two truckloads of road base. The goal was to improve drainage by building a gentle hump in the middle so water flows toward the sides. We also installed sump points along the edges (you can’t fully see them yet).
To pump the water out, we used a:
- bucket with a hole in the bottom
- sump pump with layflat pipe and a few joiners
- short pipe setup into the low point
We set up one pump on the side initially, then another where we had a low spot in the center.
After the gravel was laid, we brought in the 14-tonne roller and recompacted the platform.
The trade-off (and why we had to move fast)
Because the ground underneath was still wet, the new road base sits as a separate layer on a damp base instead of bonding into it (a lamination layer). It's not ideal, but the contractor asked for it, so we did it and had the platform reinspected. The perfect approach would be to wait about two weeks for everything to dry, but we don't have that luxury, and we don't want to pay the contractor remobilisation costs to reschedule their crew and machinery.
Once the 40-tonne rig starts moving around, any loose layers can get damaged, so time matters.
Sheet piling setup is underway
The crew are rigging up the equipment now. They've taken possession of the site, so we're staying out of their way and letting them do what they do. They'll finish their setup this afternoon.
Vibration monitoring is installed
We also had the geotech team back today to install and run vibration monitoring.
We've installed three sensor points around the site.
We've also marked the grid lines and where the external walls will sit (the blue lines). I've given the crew the required height for the sheet piles so we don't need to cut the tops off later.
Monitoring tech (and big thanks)
This vibration monitoring system took about two days to configure.
Huge thanks to Bruno at Convergence Instruments in Canada. The instrument is fantastic and very affordable: the subscription is about $185 a year, and the data streams live for monitoring.
We set up a Ubiquiti router to connect the devices. Right now they're the only devices on that network.
PacGeo's vibration monitoring covers all three points, including the fence area, and the geotech team gets an alert if vibration goes over the limit.
We also have our own real-time monitoring running on-site.
What’s next
That's the last five days. I'll share another update video once they start pre-drilling.
