Nick Ryland Barton

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Questions related from Nick Ryland Barton

Have we now a majority of engineering geologists just assessing GSI and feeding or performing continuum models with so-called Hoek-Brown rockmasses?

Recently it was discovered that GSI - a very simplified way to characterize rock masses - was appearing 16 times in the H-B equation for 'c' for rock masses, and 12 times in the H-B equation for...

22 January 2025 8,633 1 View

Young researchers given TBM prognosis analysis thesis tasks by professors, with unintended errors made but not found by reviewers. Who is responsible?

There seems to be an increasing number of MSc or PhD studies by young students with little tunnelling or TBM experience. They compare numerous established prognosis methods, and regrettably make...

19 January 2022 6,173 3 View

‘Q-system Barton’ in Google results in NGI site twice and Palmstrøm. Originators Barton and Grimstad pushed aside. Unfortunate as several NGI errors?

Engineering geologists may know that the originators of the empirical (a posteriori) Q-system method of rock mass classification for single-shell tunnel and cavern support estimation, were Barton...

14 December 2020 5,347 3 View

Many are comparing Q, RMR, RMi with GSI/Hoek-Brown/RocScience Phase 2, and imagine 'correction' through 'plastic zone' study. Is this not remarkable?

There are so many tunnel excavations, and so many who use either 'observational' (maybe double-shell) NATM or single-shell B + S(fr) selection from Q, or RMR, or less frequently RMi. Many then ask...

22 April 2020 3,900 9 View

Why do we so often see linear shear strength envelopes for intact rock and fractures in US university and oil company literature?

For many decades the strong non-linearity of the shear strength of intact rock and of non-planar fractures has been well documented, at least when considering wide variations in effective normal...

09 January 2019 5,801 4 View

Does anyone know how to delete erroneously-linked-to-we, not the author or co-author Google Scholar citations, without trying to reach publishers etc?

Very frustrating to not know how to do this!

14 September 2018 6,540 2 View

Suddenly again, a lot of literature links for spalling and fracturing around deep tunnels. Have researchers seen the recent explanation of 0.4 UCS?

Baotang Shen, the developer of FRACOD, using classic theory linking stress anisotropy and Poisson's ratio to explain exceedence of critical extension strain in a fully 3D compressive stress field,...

16 April 2018 6,294 4 View

Since distinct element modelling was developed, one sees many instances of too high shear stiffness, sometimes even put equal to Kn. Why is this?

Shear stiffness Ks is an entirely different parameter to normal stiffness Kn, despite being given the same units such as MPa/mm or the equal GPa/m. Because Ks is doubly scale-dependent (peak shear...

05 April 2018 9,811 9 View

A small tunnel, well monitored for inflow in the Stripa SCV project experienced reduced inflow compared to predictions. What about large excavations?

Quote from TUST article of 2010, just seen: During tunnel excavation in a jointed rock mass, significant joint closure takes place in the immediate vicinity of tunnel due to joint effective...

16 December 2017 5,760 2 View

JRC was developed long ago - 1973. By now there are about 50 equations associated with JRC. But almost nobody uses 3D tilt tests, as intended. Why?

The 'standard' set of 10 JRC profiles, chosen from about 400 measurements on 130 joint profiles, are 2D and for guidance only. Of course subjective in nature when used for estimation. Why so few...

14 December 2017 3,154 0 View

Do geophysicists still assume that the polarized, fast axis of shear waves may indicate the presence of a set of stress-aligned reservoir fractures?

If so then there might be two problems. The minimum (perpendicular) effective stress of tens of MPa at reservoir depth may close this fracture set unless mineral-filled with 'frozen' apertures, or...

02 December 2017 6,132 0 View

Does anyone have examples of sub-horizontal hydraulic fractures, sometimes with gravel, sand, as a result of ice-sheet melt?

With water pressure from melting surface water sometimes exceeding the vertical ice load of 1 or 2 km, sub-horizontal hydraulic fractures are sometimes (often?) found some 10's of meters below...

27 November 2017 9,969 1 View