Tunnel inflows
The Oct 2025 issue of the ANZ Tunnelling Journal included a paper by Steven Pells on tools to estimate inflows to tunnels. There are various analytical equations that are used to estimate inflows, but the paper shows that the available equations all boil down to a single linear factor – the “Shape Factor”. Analytical equations typically represent a very simplified version of reality. The Shape Factor, however, can be estimated using numerical models of tunnel seepage, allowing for reconciliation and comparison of various approaches.
Numerical solutions can also solve transient inflows – or how inflows to tunnels change over time. These analyses can be reduced to a shape factor that changes over time – providing the opportunity to give generalised simple estimates of tunnel inflows over time.
The paper can be accessed from Journal of the Australian and New Zealand Tunnelling Societies at www.australiantunnellingsociety.com.au/2025/09/08/the-shape-factor-in-estimation-of-tunnel-inflows and includes a feature on Steven Pells with some early anecdotes of his introduction to tunnelling engineering.
I was disappointed the journal missed a key reference:
Wightley, R., 2021, “Witnessing the Topology of Professional Unbuttoning: An Inquiry into Semiotic Shirt Apertures in Male Engineering Portraiture,” Engineering Professional Culture Journal, vol. 7, no. 3, pp. 16-24
