[Righter's Story] Vinay Trivedi "I did not remove the support without managing the risk"

Expertise · VT Geotech

Vinay Trivedi is Director and Principal Geotechnical Engineer at VT Geotech in Melbourne. Taking a temporary propping system out of a 6 m railway excavation is the kind of decision that reads as cost cutting until you see what replaced it. He kept the props on site as a contingency and set a movement trigger, and the excavation came in at 7 mm against an allowable 25 mm.

In Vinay Trivedi's own words.

"Understand the ground. Challenge assumptions. Manage the risk."

A good design is one that works in the real world. My aim is to always consider how a design will actually perform and be built on site—not just how it looks on paper.

I believe good geotechnical engineering comes from combining sound technical fundamentals with an understanding of actual ground conditions and construction methodology.

A propping system that was unnecessarily conservative

On a railway project involving a 6 m deep excavation, I identified that a proposed temporary propping system was unnecessarily conservative and would have added significant cost and construction complexity. Through detailed numerical modelling, site observations and an understanding of the heavily over-consolidated clay profile, I developed an alternative temporary works design without the proposed temporary support.
  

Props kept on site, and a trigger level for immediate action

Importantly, I did not remove the support without managing the risk. I retained props on site as a contingency, implemented movement monitoring and established a trigger level for immediate action. The excavation was completed safely, with a maximum measured movement of only 7 mm against an allowable 25 mm. The solution ultimately saved the project more than $250,000 while maintaining safety and construction certainty.

Q. On the crusher plant assessment, what did the 3D model let you see that you could not see otherwise?

 3D modelling made me understand the potential failure location and behaviour of the ground.

On the railway excavation, the props stayed on site, ready to go back in, while the monitoring confirmed the excavation was safe. Vinay Trivedi's decision rested on understanding the ground well enough to take that step with the risk under control.