Nick Ryland Barton

Nick Barton & Associates · Rock Engineering

Construction of dams, tunnels and slopes in jointed, water-bearing rock causes complex interactions between joint deformation and effective stress. Joint deformation can take the form of normal closure, opening, shear and dilation. The resulting changes of aperture can cause as much as three orders of magnitude change in conductivity at moderate co...

The feasibility of excavating caverns of very large span for underground siting of nuclear power stations in Norway was investigated in the early 1970s. In the end, the 1994 Winter Olympic Games provided the necessary impetus for utilizing a very large engineered rock cavern and proving its general feasibility. The 62m span Olympic Ice Hockey Caver...

Engineering Classification of Rock Masses for the Design of Tunnel Support An analysis of some 200 tunnel case records has revealed a useful correlation between the amount and type of permanent support and the rock mass qualityQ, with respect to tunnel stability. The numerical value ofQ ranges from 0.001 (for exceptionally poor quality squeezing-gr...

Rock joints exhibit a wide spectrum of shear strength under the low effective normal stress levels operating in most rock engineering problems. This is due to the Strong influence of surface roughness and variable rock strength. Conversely, under the high effective normal stress levels of interest to tectonophysicists the shear strength spectrum of...

Simple, inexpensive index tests suitable for application to jointed core or jointed blocks of rock are described. These provide quantitative data on joint roughness, joint wall strength and residual friction angle, suitable for waste repository characterization. These three parameters form the basis of a new constitutive law of rock joint behavior...

There are hundreds, if not thousands of published articles in rock mechanics journals involving Evert Hoek's GSI and the Hoek-Brown equations developed for assumed rock mass 'parameterization' for 'c' and 'ϕ' and 'σ cm' and 'E modulus'. Yet the shear strength equations are based only on a modified intact rock strength criterion. The latter is more...

The three authors Barton, Grimstad and Panthi are responding with their viewpoints concerning what is considered an exaggerated critique of NMT by Brox from Canada. This was recently published in Hydropower and Dams and our response is now published in the Forum of H&D, 2024.

Power point presentation of Oslo lecture: Q-based developments during the last 50 years. November 2024. Q for tunnel support. Parameters that can be estimated from Q. Qtbm for TBM prognosis with emphasis on actual AR advance rate. Qslope for selecting angles for unreinforced rock slopes.

The Q system was published in 1974 with senior NGI colleagues Lien and Lunde. Some details of rock mass classification will be summarized first. Co-author Grimstad was responsible for a very extensive increase in tunnel 'case records' and details regarding fibre-reinforced shotcrete S(fr) and the stress parameter SRF based on experiences from road...

The three authors Barton, Grimstad and Panthi are responding with their viewpoints concerning what is considered an exaggerated critique of NMT by Brox from Canada. This was recently published in Hydropower and Dams and our response is now published in the Forum of H&D, 2024.

This highly illustrated article, with quite limited text, is basically an abstract followed by many figures and figure texts, with short introductions to new topics. It ends with a reference list that goes beyond Barton and Choubey [1]-which is where many published articles 'stop' in relation to referencing the author's work with JRC. The BB criter...

Eda Quadros was president of the ISRM from 2015 to 2019. She was also vice-president from 2003 to 2007. She was the first woman to have had either of these ISRM roles. So as her husband from 2000 this was also something new, and a very rewarding conference-focussed addition to our professional and private life together. By very good fortune her str...

The Q-slope method for rock slope engineering provides an empirical means of assessing the stability of rock slopes in the field. It enables geotechnical engineers and engineering geologists to make adjustments to slope angles as ground conditions become apparent during the excavation of reinforcement-free slopes in civil engineering and mining pro...

Accurate measurement of the evolution of rock joint void geometry is essential for comprehending the distribution characteristics of asperities responsible for shear and seepage behaviors. However, existing techniques often require specialized equipment and skilled operators, posing practical challenges. In this study, a cost-effective photogrammet...

Intact brittle rock can fail in tension even when all principal stresses are compressive. This is due to lateral expansion and extension strain when near to a free surface, caused by Poisson’s ratio. Exceeding tensile strength due to stress anisotropy and Poisson’s ratio are the fracture-initiating conditions around deep tunnels, not the increasing...

Time, tunnel length, geology - therefore Qtbm is the title and summarizes the intention. In detail the case records, including world records, all point to the importance of accepting a time-dependent and length-dependent advance rate AR which gives different results compared to the popular tendency to focus on net penetration rate PR prognoses. In...

Pre-grouting is an effective way of displacing water and severely limiting inflow to tunnels, if practiced correctly. Joint sets are successively sealed, and permeability tensors are known to rotate and reduce in magnitude for each set. This has been measured during 3D permeability tests. In fact, the needs for tunnel support and reinforcement are...

NB&A Oslo. www.nickbarton.com Rock masses are by definition assemblies of rock blocks separated by joint sets and less frequent faults. Of course they can be very massive too. Over the years quite accurate methods have been developed for numerical modelling of what are often 'block assemblies', both in 2D (UDEC-MC, UDEC-BB) and in 3D (3DEC-MC). Man...

The fundamental differences between Q-based single-shell NMT (Norwegian) and double-shell NATM (Austrian) are explored, with emphasis on the avoidance of lattice girders in NMT, and emphasis on the problems with overbreak on stability and concrete volumes in the case of NATM. Over-break problems apply much less to NMT since over-break is not filled...

Pre-injection of rock masses ahead of tunnels needs to be done at high pressure if joints are tight - but leaking - and the rock is hard. It is desireable to cause local joint jacking as pressure loss is so rapid in the first 1m into any joint plane while flow is ocurring. Close valve when flow stops. Do not use the filter-pump, do not compare grou...

GSI has been applied for about 30 years and JRC for about 50 years. They are associated with either the Hoek-Brown based shear strength criterion for rock masses and continuum modelling, or with the Barton-Bandis based shear strength criterion for rock joints for use in discontinuum modelling. The latter, using input parameters JRC, JCS and φr prov...

GSI has been applied for about 30 years and JRC for about 50 years. They are associated with either the Hoek-Brown based shear strength criterion for rock masses and continuum modelling, or with the Barton-Bandis based shear strength criterion for rock joints for use in discontinuum modelling. The latter, using input parameters JRC, JCS and φ r pro...

A vital source event for this article is the formation of probably non-planar rock joints, and some planar ones too, at an in situ temperature different from the approx. 20 degrees C of a future laboratory. We will have cooled and unloaded the joints in question when they are recovered. When we carry out normal closure or permeability testing we wi...

The best methods of limiting water-inflow into tunnels and thereby preventing damage to the surface in case of clay deposits are well proved in some countries but poorly executed in others. This article explores the controversies and suggests the best ways of pre-grouting in jointed rock.

This extended Muller Lecture: Empiricism, Theory, and Problem Solving in Rock Engineering was given in London and Hong Kong in 2013. The file from 2013 in RG has 'lost' many figures which are black screens. This is a replacement. Warning: 2 hours when presented, 5 minutes to flash through.

A web-site used for 10 years and providing (of course free) down-loads of some 300 articles on rock mechanics and rock engineering for those interested, has been 'missed' by several. It was tough to recover a site 'inherited' by a new host.

Abstract: The joint roughness coefficient (JRC), introduced in Barton (1973) represented a new method in rock mechanics and rock engineering to deal with problems related to joint roughness and shear strength estimation. It has the advantages of its simple form, easy estimation, and explicit consideration of scale effects, which make it the most wi...

In recent keynote lectures the author of this brief 'opinion piece' has utilized variants of the title: 'Continuum or Discontinu-um'-adding 'that is the question' and also 'GSI or JRC'? The reason for such titles is the last 20 years or so of numerical modelling practice for tunnel design and rock slope stability checks. These have seemingly been d...

The NTNU and QTBM methods of prognosis are widely used for performance predictions and cost estimates in the planning and risk management of Tunnel Boring Machine (TBM) excavation projects. The methods have been applied for the evaluation of recently completed hard rock TBM projects, both during geological pre-investigations and prognosis and durin...

Several decades ago there was a strong focus on the need for discontinuum modelling to improve upon the empirically based analysis of excavations in jointed rock. The remarkable codes developed by Peter Cundall: UDEC and 3DEC were put to full use in the nineteen eighties and nineties. For example, Q-system based cavern support could be verified or...

Performance predictions and cost estimates are often decisive in the selection of excavation methods and have a major influence on the planning and risk management of Tunnel Boring Machine (TBM) excavation projects. A process of great complexity is involved during tunnel boring. When hard-to-very hard rock (i.e., low-to-extremely low boreability),...

Fractures such as faults and joints often dominate the mechanical strength and deformation of rock masses. It is thus of central importance to adopt an appropriate joint constitutive model in geomechanics simulations so that the behaviour of fractures can be realistically represented. Over the past decades, various joint constitutive models have be...

Dr Carranza-Torres has kindly pointed out an erroneous reference to a pit slope failure in Figure 47, p. 28 - which was a reproduction of his Eurock keynote Figure 1 of 2021. The planar failure surface was mistaken by NRB for the Bingham Canyon failure. Apologies. In fact earlier authors Lorig et al 2009 describe this failure as a wedge failure tha...

Rock masses are by definition assemblies of rock blocks separated by joint sets and less frequent faults. Over the years quite accurate methods have been developed for numerical modelling of these assemblies, both in 2D (UDEC-MC, UDEC-BB) and in 3D (3DEC-MC). We have used them for studying how tunnels, caverns and slopes might perform when excavate...

This paper was for a Workshop held in Madrid during 2006. The writer was not allowed to present this material. Very soon afterwards there was the tragic collapse of the Pinheiros station cavern, due to an unexplored ridge-of-rock despite five close-by boreholes, one in cavern centre. The paper emphasises the risk involved with too shallow metro pro...

Which is faster and more economic and less risk-enhancing: shallow or deeper siting of city road and metro? Two recent letters concerning a road project in Jerusalem and concerning the huge metro expansion in Moscow. Is it really cheaper 'to go shallow' with associated soil and saprolite stability problems, or is it cheaper and faster to go deeper?...

Selected aspects of NMT are described in some detail. Tunnelling in jointed rock that may be clay-bearing and faulted is assumed, with a typical wide range of Q of at least 100 down to 0.01, or roughly RMR = 80 down to 20, but not needing double-shell NATM. Selected aspects to be discussed will be the three principle EDZ, two of them representing t...

Strong opinions about GSI and H-B which match and extend some of the critical assessments in the literature. Continuum modelling may be mis-leading us too far along the road of a priori assumptions and black-box solutions. There was a move towards discontinuum methods 30-40 years ago, and we urgently need to return there after a twenty years deviat...

The big dilemma: continuum with GSI and H-B or discontinuum with e.g. UDEC, UDEC-BB, 3DEC and taking longer time to produce something more realistic. Recent critique of GSI and attempts to quantify better are briefly reviewed. The extraordinary equations that produce the nice curves of shear strength are questioned, as one loses any sense of geolog...

This paper deals with the exploration of failure modes in rock and rock masses. Failure in tension initially applies in deep tunnels, and extension failure also applies to cliffs and mountain walls. In each case a free surface is present. However, shear strength applies to the maximum mountain heights since confined compression strength is too high...

Extension strain and failure in tension does a much better job in explaining and quantifying failure in tunnels, cliffs and mountain walls than Mohr-Coulomb shear strength components c and phi since intact rock has too high cohesion. M-C is good for rockfill and soil - presumably. In the case of the highest mountains, the critical state (maximum po...

Development of the Q-system has meant engagement in water transfer tunnels, hydropower headrace and pressure tunnels in many countries since 1974. The support requirements of single-shell tunnels, were initially dominated by Norwegian and Swedish hydropower projects. The Q-system data base was greatly expanded later, by Grimstad's incorporation of...

For those interested in distinct element (jointed) models such as UDEC-BB and for input to 3DEC. A more interesting form of rock mechanics than continuum modelling - and more accurate too. Can be used for scoping coupled-behaviour with flow on the joints towards tunnels. Of course 2D limitations. But mechanisms of importance are illustrated - as pa...

More extensive references to the use of the JRC-based criterion, going far beyond the 1977 'limit' of many referencing the method.

Details related to ‘the ten’ JRC profiles and further work with the Barton-Bandis criterion – why JRC, JCS and φr. Abstract-Introduction to numerous figures. This highly illustrated article, with minimal text, is basically an abstract followed by many figures and figure texts. It ends with a reference list that goes beyond Barton and Choubey, 197...

For those who wish to work as an engineering geologist when logging core boxes or e.g. 5m lengths of tunnel advance (as opposed to guessing a GSI number - or 5 per core box, 5 per tunnel advance ??) then you can use the Q-histogram method that I have been using since 1987. It is much easier (faster) than trying to think of one representative Q-para...

The four lectures have content DETAILED in the document. 1. THE MANY FACES OF Q 2. SHEAR STRENGTH of ROCK, ROCK JOINTS and ROCK MASSES: PROBLEMS and SOME SOLUTIONS 3. USING DEEP TUNNELS, CLIFFS, MOUNTAIN WALLS, MODELS AND MOUNTAINS: TO EXPLORE FAILURE MODES IN ROCK AND ROCK MASSES 4. TBM PERFORMANCE: CASE RECORD ANALYSIS including FAULTS, AND RECE...

A brief glimpse of a forgotten period at rock mechanics conferences, when there was time for authors to be questioned, provide answers, and later have the discussions published as ‘Vol. 2’. The ‘Rock Fracture’ symposium of ISRM in Nancy, France in 1971 was the first for some of the freshly graduated Ph.D. students from Imperial College. Here there...

The frequent assumption of those who feel they know best is that the Q-system only applies to typical hard jointed rocks. A prominent critic has even unilaterally suggested limiting the range of application of the Q-value to what he has assumed is likely to apply. The above were not the intention of the developer who did the interpretation of the o...

This final chapter is designed to act as a cross-discipline reference point between rock mechanics and engineering geological behaviour in the ‘static’ world of slow-andmacro deformation processes, and the geophysicists ‘dynamic’ world of fast-and-micro deformation and attenuation processes. That there are important links between the two in terms o...

An analysis of some 200 case records has revealed a useful correlation between the amount and type of permanent support and the rock mass quality Q, with respect to excavation stability. The rock mass quality Q is a function of six parameters,each of which has a rating of importance,which can be estimated from surface mapping and can be updated dur...

This is the written question and answer Discussion of, in this case the Q-system paper by Barton, Lien and Lunde, 1977. The conference was held in Minnesota in 1975. Among others are discussions by Bieniawski, Bergman, Cundall, Franklin.

This paper has not been on-line before. Barton, N., Lien, R. & Lunde, J. 1977. Estimation of support requirements for underground excavations. Proc. of 16th Symp. on Design Methods in Rock Mechanics, Minnesota, 1975. pp. 163-177. ASCE, NY. Discussion pp. 234-241. It is the first conference presentation of the Q-system, in 1975, with compendium from...

Development of the Q-system has meant engagement in water transfer tunnels, hydropower headrace and pressure tunnels in many countries since 1974. The support requirements of single-shell tunnels, were initially dominated by Norwegian and Swedish hydropower projects. The Q-system data base was greatly expanded later, by Grimstad's incorporation of...

Negative results with a difference. A 2021 wish for a better year after the destruction of 1km of thin but beautiful sea ice representing 2D isotropy, converted by the adverse winds of 2020 into 10m of chaotic anisotropy and loss of life for those pieces discarded.

This paper deals with the exploration of failure modes in rock and rock masses, starting with extension failure in deep tunnels, followed by analysis of the limited heights of cliffs, mountain walls and mountains. Here, tensile failure applies to the cliffs and mountain walls, since cohesive strength is too high, and shear strength applies to the m...

3D physical model studies of excavated-under-stress tunnels or circular caverns are compared with 2D elasto-plastic solutions. Due presumably to the development of log-spiral shear surfaces, it is found that the estimated maximum stress in relation to the uniaxial compression strength is much higher than tolerated by hard brittle rocks prior to vio...

The TBM prognosis-method people have so far remained silent, so let me hazard a first response. As a briefest possible summary of past and published case-record-based opinions let us first consider that a project has a major portion that is too deep for borehole investigation, unless there is a mining company involved who are more-than-usually inte...

The paper is a short resume of the author's experiences in various nuclear waste related research projects and actual planned repository characterization work. Several projects in the USA and several in Sweden, a major six-year study in the UK, and two volume reporting of the BB model in Canada. The work spanned 30 years, but if siting of nuclear p...

Q-slope is an empirical rock slope engineering method for assessing the stability of excavated rock slopes in the field. Intended for use in reinforcement-free road or railway cuttings or in open cast mines, Q-slope allows rock engineers to make potential adjustments to slope angles as rock mass conditions become apparent during excavation. Q-slo...

We read at intervals in excellent journals, or publish or lecture about what can go seriously wrong in our challenging underground media. It may be the occasional, easily explained, locally massive failures in single-shell tunnels, or the occasional, easily explained, locally massive failures in double-shell tunnels (or caverns under construction)....

An observant Ph.D. student, Kieran Gilmore, from Cambridge University Earth Science Department was recently kind enough to inform the surviving author of the BB joint constitutive model (Stavros Bandis left us suddenly in 2014) that there was a ‘typo’ in the frequently RG referenced Bandis et al. 1983 paper. The errors concerned two negative signs....

Failure of brittle rock is often associated with explicit fracturing events. Understanding fracturing behavior of rock masses has become a critical endeavour for not only civil engineering but also geological radioactive waste disposal, deep mining, geothermal energy extraction and CO2 geo-sequestration. Numerical simulations are vital tools for th...

Others did this first. Degrade c, mobilize phi. But for progressive failure understanding (always applies?) need four components: crack, crunch, scrape, swoosh: intact bridges fail, new fractures shear, capable joints shear, capable faults/clay-filled discontinuities shear - in a progressive manner.

Single-shell tunnel design and execution, typical of NMT and Q-system based support design is contrasted with double-shell tunnel design and execution, typical of NATM. The particular advantages of fibre-reinforced shotcrete compared to mesh-reinforced or concrete final linings, in the case of drill-and-blast and Jn/Jr > 6 caused overbreak are emph...

Rough joints can over-close due to a prior higher stress, or due to temperature increase alone. There is better fit of their opposing walls causing increased friction and even tensile strength. Well-controlled laboratory HTM tests, in situ HTM block tests, and large-scale heated rock mass tests, lasting several years at Stripa, Climax and Yucca Mou...

King, 2005 recently summed up the major exploration-related goals of rock physics research. They are 'to understand how lithology, porosity, confining stress and pore pressure, pore fluid type and saturation, anisotropy and degree of fracturing, temperature, and frequency influence the velocities and attenuation of compressional P-and S-waves in se...

1. INTRODUCTION TO Q-PARAMETERS, CORE LOGGING, UNEXPECTED ERROR IN A GEOLOGIC INVESTIGATION 2. NMT – NATM CONTRASTED, SHOTCRETE, BOLTS, RRS, LATTICE GIRDERS, OVER-BREAK AND CONSEQUENCES 3. TUNNEL AND CAVERN DEFORMATION, RELATIVE COST AND TIME 4. SEISMIC VELOCITY, DEFORMATION MODULUS, DEPTH 5. LIMITATIONS OF SHEAR STRENGTH MODELS, MODELLING 6....

The Q-system for rockmass, core and tunnel logging was used extensively in the TransManche Link TBM tunnelling, and also in a consortium claim against owner Eurotunnel in the early 1990s. In this connection, the Q-system was also used by the first author for logging precedent conditions in local tunnels in chalk marl, and by the construction consor...

The term ‘characterisation’ will be used to describe methods of collection and interpretation of the physical attributes of the joints and other discontinuities, in other words those which control their mechanical and hydraulic properties, and the behaviour of jointed rock as an engineering medium. Rock discontinuities vary widely in terms of their...

The apparent 8 to 9km height limit of mountains will be addressed using critical state shear strength arguments, since confined compression strength is too high to explain these 'limited' heights. Modified Mohr Coulomb criteria have been derived based on critical state mechanics for rocks. These criteria are utilised to obtain estimates of maximum...

The Q-system for rockmass, core and tunnel logging was used extensively in the TransManche Link TBM tunneling, and also in a consortium claim against owner Eurotunnel in the early 1990's. In this connection, the Q-system was also used by the first author for logging precedent conditions in local tunnels in chalk marl, and by the construction consor...

The Q-slope method for rock slope engineering was developed to allow engineering geologists and rock engineers to rapidly assess the stability of excavated rock slopes in the field, and make optimal adjustments to slope angles as rock mass conditions become apparent during the construction of road cuts or benches. An empirical relationship between...

The Q-slope method for rock slope engineering was developed to allow engineering geologists and rock engineers to rapidly assess the stability of excavated rock slopes in the field, and make optimal adjustments to slope angles as rock mass conditions become apparent during the construction of road cuts or benches. An empirical relationship between...

The strength of rock and rock masses is poorly represented by Mohr-Coulomb. Adding cohesive and frictional components is not consistent with reality. Failure may initiate and propagate via the overcoming of up to four strength components, perhaps five if we add block-rotation mechanisms. When the rock is more massive, or is with no 'capable' joint...

In relation to soil, rock is usually extremely strong, with a compression strength that will seldom be mobilized, even in deep tunnels. Intact rock may also have cohesion that is so high that it makes mountain avalanches rare events. Frictional strength tends to be high as well, due to the big contribution of dilation unless the rock has high poros...

Pre-grouting ahead of tunnels has three main functions: to control inflow into the tunnel, to limit groundwater drawdown above the tunnel, to make tunnelling progress more predictable since rock mass quality is effectively improved. It helps to avoid settlement damage caused by consolidation of clay deposits beneath built up areas, since towns tend...

Pre-grouting ahead of tunnels has three main functions: to control water inflow into the tunnel, to limit groundwater drawdown above the tunnel, and to make tunnelling progress more predictable since rock mass quality is effectively improved. It helps to avoid settlement damage caused by consolidation of clay deposits beneath built-up areas, since...