Nonlinearity of the Rock Joint Shear Strength
The triaxial testing for irregular or unfilled rock joints was conducted on the rock mechanics test system (MTS). A series of axial failure stresses under different confining pressures applied to the same specimen was continuously acquired on MTS. The corresponding normal and shear stresses acting o...
Gespeichert in:
| Datum: | 2015 |
|---|---|
| Hauptverfasser: | , , |
| Format: | Artikel |
| Sprache: | English |
| Veröffentlicht: |
Інститут проблем міцності ім. Г.С. Писаренко НАН України
2015
|
| Schriftenreihe: | Проблемы прочности |
| Schlagworte: | |
| Online Zugang: | http://dspace.nbuv.gov.ua/handle/123456789/173286 |
| Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Zitieren: | Nonlinearity of the Rock Joint Shear Strength / Y.F. Wei, W.X. Fu, D.X. Nie // Проблемы прочности. — 2015. — № 1. — С. 231-239. — Бібліогр.: 22 назв. — англ. |
Institution
Digital Library of Periodicals of National Academy of Sciences of Ukraine| id |
irk-123456789-173286 |
|---|---|
| record_format |
dspace |
| spelling |
irk-123456789-1732862020-11-29T01:27:11Z Nonlinearity of the Rock Joint Shear Strength Wei, Y.F. Fu, W.X. Nie, D.X. Научно-технический раздел The triaxial testing for irregular or unfilled rock joints was conducted on the rock mechanics test system (MTS). A series of axial failure stresses under different confining pressures applied to the same specimen was continuously acquired on MTS. The corresponding normal and shear stresses acting on the rock joint plane were calculated in terms of LEFM. The Mohr–Coulomb (MC) shear strength parameters of each specimen could be determined by linear regression analysis. Thirteen specimens were taken from the dam site drill rock cores of a hydropower station. The scatter of points plotted for all test results in the normal and shear stress space exhibits obvious nonlinearity. Test results show that it would be more convenient to describe the shear strength of rock joints in the nonlinear form. The comparison and discussion of three function fittings proved that the well-known Barton criterion was more appropriate for describing the shear strength of rock joints. Стыки породы неправильной формы или содержащей пустоты исследовали на оборудовании для механических испытаний горных пород при трехосном сжатии. Ряд осевых разрушающих напряжений при различных горных давлениях, прилагаемых к одному и тому же образцу, получали на испытательном оборудовании в непрерывном режиме. Соответствующие нормальные и касательные напряжения, действующие на плоскость стыка породы, рассчитывали, используя подходы линейной механики разрушения. Параметры сопротивления сдвигу Мора Кулона для каждого образца определяли с помощью линейно-регрессионного анализа. Тринадцать образцов были изготовлены из кернов, вырезанных у створа плотины гидроэлектростанции. Разброс точек, графически представленный для всех результатов испытаний в области нормальных и касательных напряжений, имеет выраженную нелинейность. Результаты показывают, что сопротивление сдвигу на стыке породы удобнее описывать в нелинейном виде. Сравнение и обсуждение трех аппроксимаций функции подтвердили, что наиболее подходящим для описания сопротивления сдвигу на стыках породы является хорошо известный критерий Бартона. 2015 Article Nonlinearity of the Rock Joint Shear Strength / Y.F. Wei, W.X. Fu, D.X. Nie // Проблемы прочности. — 2015. — № 1. — С. 231-239. — Бібліогр.: 22 назв. — англ. 0556-171X http://dspace.nbuv.gov.ua/handle/123456789/173286 539.4 en Проблемы прочности Інститут проблем міцності ім. Г.С. Писаренко НАН України |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| language |
English |
| topic |
Научно-технический раздел Научно-технический раздел |
| spellingShingle |
Научно-технический раздел Научно-технический раздел Wei, Y.F. Fu, W.X. Nie, D.X. Nonlinearity of the Rock Joint Shear Strength Проблемы прочности |
| description |
The triaxial testing for irregular or unfilled rock joints was conducted on the rock mechanics test system (MTS). A series of axial failure stresses under different confining pressures applied to the same specimen was continuously acquired on MTS. The corresponding normal and shear stresses acting on the rock joint plane were calculated in terms of LEFM. The Mohr–Coulomb (MC) shear strength parameters of each specimen could be determined by linear regression analysis. Thirteen specimens were taken from the dam site drill rock cores of a hydropower station. The scatter of points plotted for all test results in the normal and shear stress space exhibits obvious nonlinearity. Test results show that it would be more convenient to describe the shear strength of rock joints in the nonlinear form. The comparison and discussion of three function fittings proved that the well-known Barton criterion was more appropriate for describing the shear strength of rock joints. |
| format |
Article |
| author |
Wei, Y.F. Fu, W.X. Nie, D.X. |
| author_facet |
Wei, Y.F. Fu, W.X. Nie, D.X. |
| author_sort |
Wei, Y.F. |
| title |
Nonlinearity of the Rock Joint Shear Strength |
| title_short |
Nonlinearity of the Rock Joint Shear Strength |
| title_full |
Nonlinearity of the Rock Joint Shear Strength |
| title_fullStr |
Nonlinearity of the Rock Joint Shear Strength |
| title_full_unstemmed |
Nonlinearity of the Rock Joint Shear Strength |
| title_sort |
nonlinearity of the rock joint shear strength |
| publisher |
Інститут проблем міцності ім. Г.С. Писаренко НАН України |
| publishDate |
2015 |
| topic_facet |
Научно-технический раздел |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/173286 |
| citation_txt |
Nonlinearity of the Rock Joint Shear Strength / Y.F. Wei, W.X. Fu, D.X. Nie // Проблемы прочности. — 2015. — № 1. — С. 231-239. — Бібліогр.: 22 назв. — англ. |
| series |
Проблемы прочности |
| work_keys_str_mv |
AT weiyf nonlinearityoftherockjointshearstrength AT fuwx nonlinearityoftherockjointshearstrength AT niedx nonlinearityoftherockjointshearstrength |
| first_indexed |
2025-07-15T09:55:36Z |
| last_indexed |
2025-07-15T09:55:36Z |
| _version_ |
1837706356190085120 |
| fulltext |
UDC 539.4
Nonlinearity of the Rock Joint Shear Strength
Y. F. Wei,
a,1
W. X. Fu,
b
and D. X. Nie
a
a State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University
of Technology, Chengdu, China
b State Key Laboratory of Hydraulic and Mountain River Engineering, Sichuan University, Chengdu,
China
1 weiyufeng@cdut.edu.cn
The triaxial testing for irregular or unfilled rock joints was conducted on the rock mechanics test
system (MTS). A series of axial failure stresses under different confining pressures applied to the
same specimen was continuously acquired on MTS. The corresponding normal and shear stresses
acting on the rock joint plane were calculated in terms of LEFM. The Mohr–Coulomb (MC) shear
strength parameters of each specimen could be determined by linear regression analysis. Thirteen
specimens were taken from the dam site drill rock cores of a hydropower station. The scatter of
points plotted for all test results in the normal and shear stress space exhibits obvious nonlinearity.
Test results show that it would be more convenient to describe the shear strength of rock joints in the
nonlinear form. The comparison and discussion of three function fittings proved that the well-known
Barton criterion was more appropriate for describing the shear strength of rock joints.
Keywords: rock joint, shear strength, mechanics test system, triaxial testing, function
fitting, Barton criterion.
Introduction. The irregular and unfilled rock joints are quite widespread discontinuities
in the rock mass [1–5]. In addition to straightforward shear testing of discontinuities of this
type used by many researchers, an empirical formula for describing the shear strength of
rock joints has been proposed. Considering the nonlinear characteristic of the jointed rocks
and the effect of the intermediate principal stress on the strength behavior, authors [6]
modified the nonlinear form of the Mohr strength criterion. Other researchers also made
contribution to the nonlinear shear strength features of the jointed rocks on the basis of the
previous researches [7, 8].
A consistent concept accepted in the field of rock mechanics is that the shear strength
of the rock joint mainly depends on its roughness, hardness and mother rock type and has a
nonlinear feature related to stress levels. Based on the shear strength results obtained by the
simply-direct shear testing for the structural plane specimens, Barton put forward a
nonlinear empirical formula for estimating the peak shear strength of the irregular and
non-filled rock joints [9]. The Barton criterion has been wildly accepted in the field of rock
mechanics and applied to many rock engineering projects.
Generally, the in-situ direct testing is a more reliable approach to evaluating the shear
strength of the rock joints [10–13]. However, due to the difficulties and high costs of the
in-situ testing, the laboratory direct shear test method proposed by the International Society
for Rock Mechanics Commission (ISRM) is often employed to investigate the shear
strength of the rock joints [14]. The test method proposed by the ISRM, which comprises
the single and multiple specimen methods, and the corresponding experimental procedure
are described in detail by Barton [15]. In addition, Barla et al. developed a new direct shear
testing apparatus for testing the strength of rock joints as well [16]. Tatone and some other
researchers also provided the quantitative description for the surface characteristics of the
rock structural plane using some advanced tools [17]. Some new shear strength criterions
© Y. F. WEI, W. X. FU, D. X. NIE, 2015
ISSN 0556-171X. Ïðîáëåìû ïðî÷íîñòè, 2015, ¹ 1 231
were proposed for the rock joints together with the surface roughness features measured in
the laboratory shear tests [18, 19]. Jafari et al. [20] analyzed the variation of the shear
strength of the rock joints under the cyclic loading excitation, and according to their
experimental results, some mathematical models were developed for evaluating the shear
strength under the cyclic loading conditions.
In general, the study on the shear strength of the rock mass or rock joints was focused
on the theoretical analysis for determinating the strength parameter value and the
development of the advanced instrument. However, only few studies were dedicated to the
analysis of the experimental method. Considering the reliability of the experimental results,
the strength parameters of the rock joint obtained by the direct shear testing are considered
the most lucrative. Nevertheless, it is extremely difficult to guarantee the consistency of
such parameters as the roughness and hardness of the rock joint specimens. In order to
accurately evaluate the strength parameters of the rock joints, the triaxial testing method is
presented in this paper. The proposed method would be beneficial for investigating the
linear or nonlinear strength parameters of the structural planes.
The triaxial tests of the rock joints in this study were conducted using the rock
mechanics test system (MTS). The experimental procedure is similar to the general triaxial
testing for the intact rock specimens. The number of the tested specimens is thirteen in
total. These specimens were taken from the dam-site drilled rock cores of the Maerdang
hydropower station in the upstream of the Yellow river. During the triaxial testing via the
MTS, a series of axial failure stresses and confining pressures applied to the same specimen
were continuously acquired. Then within framework of the linear elastic fracture mechanics
(LEFM) the normal and shear stress components on the rock joint plane are calculated.
Herein, the MC shear strength parameters of each specimen can be determined through
linear fitting. However, the scatter point distribution of the test results for all specimens
showed an obviously nonlinear feature in the normal and shear stress space. Therefore, it
was considered more appropriate to describe the shear strength of the tested rock joint
specimens in a nonlinear form. On the basis of comparative analysis of three function
fittings for the scatter points in the normal and shear stress space, the well-known Barton
criterion describing the rock joint shear strength is proved to be appropriate.
1. Experimental Procedure. For the triaxial testing for the rock joints we employed
the MTS apparatus with a programmable servo controlling system, which consists of a
main test machine, a hydraulic power source system and a digital control system (Fig. 1).
The experimental procedure for the rock joint specimen is similar to the general triaxial
testing for the intact rock specimen. The axial load was applied gradually until the axial
failure stress �1 reached a specified confining pressure (� �2 3� ). The pressure excitation
was gradually increased until the upper part of the rock joint specimen contacted the base
plate in the specimen box, or the axial displacement exceeded the reserved displacement
space. We thus could attain multiple failure stress pairs of (�1 , � 3) for each specimen. The
strain rate during axial loading was controlled to be 0.01 mm/s. We carried out testing for a
total of thirteen specimens of rock joints taken from the dam-site drilled rock cores of the
Maerdang hydropower station located in the upper stream of the Yellow river. The mother
rock type of specimens was monzonite. The natural rock joint had completely separated
and was irregular, rough, unfilled and unbonded.
The description of the experiments can be reduced to the following:
(1) The height of each rock joint specimen was less than 100 mm and was roughly
two times the diameter. The maximum sliding distance of 10–20 mm was reserved near the
top and bottom of each rock joint specimen, respectively (Fig. 2a). Thus, the upper and
lower parts of the specimen could freely move under different confining pressures. The
triaxial testing would be terminated when the relative sliding displacement of the upper and
low parts reached the 10–20 mm reserved in advance.
Y. F. Wei, W. X. Fu, and D. X. Nie
232 ISSN 0556-171X. Ïðîáëåìû ïðî÷íîñòè, 2015, ¹ 1
(2) The confining pressures during the triaxial testing were achieved by increasing the
oil pressure in the pressure chamber. The specimens were wrapped with heat shrink films
so that each rock joint specimen did not be directly placed into the hydraulic oil. During the
wrapping process, the top and bottom blocks of specimen were kept in contact with each
other as tightly as possible. After that, the heat shrink films on both ends were heated so
that the films shrank and tightened around the surrounding area of the steel caps at two
ends of the specimen (Fig. 2b).
The single specimen method [21, 22] was employed in this study. Firstly, the
specimen was installed in the triaxial chamber by the conventional triaxial test method.
Secondly, the first level of confining pressure was loaded. Thirdly, keeping the confining
pressure constant we loaded the first axial pressure until the peak of the stress–strain curve
was directly observed through the data acquisition system of MTS. At this point, we kept
the first level of axial stress constant and loaded the second level of confining pressure.
Nonlinearity of the Rock Joint Shear Strength
ISSN 0556-171X. Ïðîáëåìû ïðî÷íîñòè, 2015, ¹ 1 233
Fig. 1. The rock mechanics test system.
a b
Fig. 2. Preparation for the tested specimen: (a) reserving sliding displacement space cut by a diamond
saw in advance; (b) wrapping with heat shrink films to prevent hydraulic oil into rock joint fissure.
Then we kept the second level of confining pressure constant until the second axial
pressure occurred. The repeat loading process for the single specimen test method is
described in Fig. 3.
During the triaxial testing for the rock joint specimen, the multiple pairs of the failure
stress state (�1 , � 3) were recorded during the experiment process. Accordingly, the normal
stress and shear stress � nj and � j on the structural plane corresponding to the each pair
of (�1 , � 3) can be calculated by Eqs. (1) and (2), which can be derived in terms of the
LEFM theory under the assumption of small strain,
�
� � � �
�nj j�
�
�
�1 3 1 3
2 2
cos , (1)
�
� �
�j j�
�1 3
2
sin , (2)
where � nj and � j are the normal stress and the shear stress on the rock joint plane, �1
and � 3 are the axial failure stress (the maximum principal stress) and the confining stress
(the minimum principal stress and � �2 3� ), and � j is the dip angle of the rock joint
plane (between the horizontal surface and the rock joint plane).
2. Test Results. The axial failure stresses of the thirteen rock joint specimens could be
obtained, as well as the corresponding confining pressures. The normal and shear stresses
calculated by Eqs. (1) and (2) can be used for exterminating the frictional angle and
cohesion for each rock joint specimen. It should be noted that, theoretically, although only
the friction angle existed at the rock joint surface when the two side rock parts of the joint
plane were completely separated in natural state, a small amount of the cohesion on the
joint plane was still observed during the shearing process. Occurrence of the cohesion was
due to the fact that the fissure wall of rock joint was rough and irregular. Figure 4 shows
the fresh irregular shear parts on the rock joint plane. A more rough and irregular rock joint
specimen would produce a larger shear stress. The clamping effect of a rough and irregular
rock joint was more significant, in particular under a high confining pressure.
234 ISSN 0556-171X. Ïðîáëåìû ïðî÷íîñòè, 2015, ¹ 1
Fig. 3. Loading process of the single specimen test method.
Y. F. Wei, W. X. Fu, and D. X. Nie
In fact, the negative cohesions that occurred in some rock joint specimens were also
caused by the fresh irregular shear parts on the rock joint plane under a high confining
pressure. The rock joint specimens that exhibited the phenomenon of negative cohesions
were relatively rare.
3. Analysis and Discussion.
3.1. Method of Fitting. Figure 5 showed the scatter points of the normal and shear
stress pairs of (� nj , � j ) for all specimens. It should be noted that the different shape or
color of the dot represented the data pair of (� nj , � j ) for each rock joint specimens under
different confining pressures. The dip angle of rock joint (� j ) and the values of the
frictional angle � j and cohesion parameter c j were also given in Fig. 5. Observation for
Fig. 5 shows that the shear stress increases with the increase of normal stress and the
relation between the normal and shear stresses was obviously nonlinear.
ISSN 0556-171X. Ïðîáëåìû ïðî÷íîñòè, 2015, ¹ 1 235
Fig. 4. The fresh irregular shear parts on the rock joint plane.
Fig. 5. The scatter point distribution in the � �nj j� space and its fitting by three functions.
Nonlinearity of the Rock Joint Shear Strength
In order to reasonably evaluate the relation between the normal and shear stresses of
the tested rock joint specimens, the curve-fitting tool in MATLAB was employed to treat
the linear Mohr–Coulomb criterion fitting, the power fitting, and the nonlinear Barton
criterion fitting. These expressions are given in Eqs (3), (4), and (5), respectively,
� � �j j nj jc� �tan , (3)
where � j is the frictional angle of the rock joint (deg) and c j is the cohesion of the rock
joint,
� �j nj
ba� , (4)
where a and b are coefficients of the power function,
� � �
�j nj b
nj
JRC
JCS
� �
�
�
�
�
�
�
�
�
�
�tan log . (5)
Here �b is the basic frictional angle of the rock joint (deg), JRC is the roughness
coefficient of the rock joint, and JCS is the compressive strength of the rock joint wall.
When fitting with the power function of Eq. (4), the natural logarithm values of the
normal and shear stresses were first calculated. Then Eq. (4) was modified to the linear
form as follows:
ln ln ln .� �j njb a� � (6)
The unknown coefficients of Eqs. (3) and (6) can be computed by the least square
method. The “general equation” module of the curve fitting tool in MATLAB was chosen
to calculate the unknown coefficients in Eq. (5). The “general equation” module allows the
user to input any form equation. During the iterative process of calculating the coefficients
of the Barton criterion, the initial iterative value should be correctly set for each coefficient,
and the initial value should fall within the possible upper and lower limits. The initial
iterative input value and the possible upper and lower limits of each parameter should
satisfy the physical significance of the Barton criterion. The fitted curves are illustrated in
Fig. 5.
3.2 Discussion. The fitted relations by three different approaches showed that the
linear MC criterion fitting is poorer than fitting with the power function or the Barton
equation. Especially, the linear MC criterion fitting would overestimate the shear strengths
of the rock joints under low normal stress. The curves fitted by a power function and the
Barton equation were almost identical and the shear strengths of the rock joints overall
demonstrated the nonlinear feature. It also proved the reliability of the triaxial test method.
Under a high normal stress the shear strengths estimated by the linear MC criterion, the
power function and nonlinear Barton criterion were overestimated. We thus only considered
the Barton criterion fitting in the following analysis.
The measured � nj and � j were first divided by the fitted JCS -value. Then the
relationship of � nj JCS against � j JCS was plotted (Fig. 6). The results in Fig. 6 were
in good agreement with the conclusions conducted by Hoek and Bray [13]. In other words,
when 0.01� �� nj JCS 0.3, the shear strengths of the rock joints estimated by the Barton
equation were relatively accurate; but when � nj JCS �0.3, the shear strengths of the rock
joints estimated by the Barton equation were overestimated. The protruding parts on the
natural and roughness joint surface would be gradually destroyed by the shear stress when
the value of the normal stress is high. At the same time, the growth rate of the shear
strength would be decreased. This characterization is not consistent with the primary
236 ISSN 0556-171X. Ïðîáëåìû ïðî÷íîñòè, 2015, ¹ 1
Y. F. Wei, W. X. Fu, and D. X. Nie
condition of the natural joint surfaces. Hence, under a high normal stress the calculation
error would be obvious when the Barton equation was employed. Most of research results
showed that the shear strength of the rock joints estimated by the Barton equation would be
on the high side when the condition of � nj JCS �0.3 was satisfied. But for the most of the
rock engineering projects, such as the slope engineering, this equation was widely used
because the value of � nj JCS normally ranges from 0.01 to 0.3.
In compliance with Barton’s conclusion, the measured shear strength under a high
normal stress falls within the range of peak and residual shear strengths when the direct
shear testing was repeatedly conducted for the same specimen. In this study, the triaxial
testing was continuously conducted under different levels of confining pressure. The shear
damage occurred at the locally rough joint surface during the sliding process under the first
few levels of confining pressure. Then the shear strength of the joint would be reduced
under the next confining pressure tests.
Conclusions. A new test method for determination of the strength parameters of the
rock joints is proposed. Some conclusions are summarized as follows:
1. The shear strengths of rock joints were directly determined by using the MST.
When controlling the confining pressure at different levels, the normal and shear stresses of
rock joints at failure were obtained. The shear strength of the joints related to stress levels
were explicitly expressed by the linear MC criterion fitting, the power function fitting and
the nonlinear Barton criterion fitting.
2. The presented test method is feasible, while its current deficiencies, such as
difficulty of sampling and error caused by different specimens, can be efficiently overcome.
The confining pressure can also be designed in terms of the actual buried depth of the
in-situ rock joint.
3. Both the power functions fitting, and the nonlinear Barton criterion fitting can
produce a more reliable nonlinear shear strength variation related to stress levels than the
linear MC criterion fitting.
ISSN 0556-171X. Ïðîáëåìû ïðî÷íîñòè, 2015, ¹ 1 237
Fig. 6 The reliable range of the rock joint shear strengths estimated by the Barton criterion.
Nonlinearity of the Rock Joint Shear Strength
Acknowledgments. The present authors thank the State Key Laboratory of Geohazard
Prevention and Geoenvironment Protection (Grant No. SKLGP2012Z011) and the National
Nature Science Foundation of China (Grant No. 40972190) for finance support. They also
thank the Mapletrans Corporation for polishing this paper.
1. F. D. Patton, “Multiple modes of shear failure in rock,” in: Proc. of the 1st Congr. of
International Society of Rock Mechanics (Lisbon, Portugal, 1966), Vol. 1, pp. 509–
513.
2. H. Bock, “A simple failure criterion for rough joints and compound shear surfaces,”
Eng. Geol., 14, No. 4, 241–254 (1979).
3. E. Hoek, “Strength of jointed rock masses,” Geotechnique, 33, No. 3, 187–223
(1983).
4. I. W. Johnston and T. S. K. Lam, “Shear behavior of regular triangular concrete/rock
joints-analysis,” J. Geotech. Eng., 115, No. 5, 711–727 (1989).
5. M. Bahaaddini, G. Sharrock, and B. K. Hebblewhite, “Numerical direct shear tests to
model the shear behaviour of rock joints,” Comput. Geotech., 51, 101–115 (2013).
6. M. Singh and B. Singh, “Modified Mohr–Coulomb criterion for nonlinear triaxial and
polyaxial strength of jointed rocks,” Int. J. Rock Mech. Min. Sci., 51, 43–52 (2012).
7. N. Barton, “Shear strength criteria for rock, rock joints, rockfill and rock masses:
Problems and some solutions,” J. Rock Mech. Geotech. Eng., 5, No. 4, 249–261
(2013).
8. L. Y. Zhang, “Estimating the strength of jointed rock masses,” Rock Mech. Rock Eng.,
43, No. 4, 391–402 (2010).
9. N. Barton, “Review of a new shear strength criterion for rock joints,” Eng. Geol., 7,
No. 4, 287–332 (1973).
10. G. Barla, F. Robotti, and L. Vai, “Revisiting large size direct shear testing of rock
mass foundations,” in: Proc. of the 6th Int. Conf. on Dam Engineering (Lisbon,
Portugal, 2011), pp. 179–188.
11. D. R. Wines and P. A. Lilly, “Estimates of rock joint shear strength in part of the
Fimiston open pit operation in Western Australia,” Int. J. Rock Mech. Min. Sci., 40,
No. 6, 929–937 (2003).
12. S. R. Hencher and L. Richards, “Laboratory direct shear testing of rock discontinuities,”
Ground Eng., 22, 24–31 (1989).
13. E. Hoek and J. W. Bray, Rock Slope Engineering, the 3rd edition, Institute of Mining
and Metallurgy, London (1981).
14. J. Muralha, G. Grasselli, B. Tatone, et al., “ISRM suggested method for laboratory
determination of the shear strength of rock joints, revised version,” Rock Mech. Rock
Eng., 47, No. 1, 291–302 (2014).
15. E. T. Brown (Ed), Rock Characterization, Testing and Monitoring – ISRM Suggested
Methods, Pergamon Press, Oxford (1981), pp. 129–140.
16. G. Barla, M. Barla, and M. E. Martinotti, “Development of a new direct shear testing
apparatus,” Rock Mech. Rock Eng., 43, 117–122 (2010).
17. B. S. A. Tatone and G. Grasselli, “An investigation of discontinuity roughness scale
dependency using high-resolution surface measurements,” Rock Mech. Rock Eng., 46,
No. 4, 657–681 (2013).
18. G. Grasselli, “Manuel Rocha medal recipient shear strength of rock joints based on
quantified surface description,” Rock Mech. Rock Eng., 39, No. 4, 295–314 (2006).
238 ISSN 0556-171X. Ïðîáëåìû ïðî÷íîñòè, 2015, ¹ 1
Y. F. Wei, W. X. Fu, and D. X. Nie
19. C. C. Xia, Z. C. Tang, W. M. Xiao, and Y. L. Song, “New peak shear strength
criterion of rock joints based on quantified surface description,” Rock Mech. Rock
Eng., 47, No. 2, 387–400 (2014).
20. M. K. Jafari, K. A. Hosseini, F. Pellet, et al., “Evaluation of shear strength of rock
joints subjected to cyclic loading,” Soil Dyn. Earthq. Eng., 23, No. 7, 619–630 (2003).
21. K. Kovari and A. Tisa, “Multiple failure state and strain controlled triaxial tests,”
Rock Mech., 7, 17–13 (1975).
22. M. R. Vergara, P. Kudella, and T. Triantafyllidis, “Large scale tests on jointed and
bedded rocks under multi-stage triaxial compression and direct shear,” Rock Mech.
Rock Eng., 47, No. 2, 541–559 (2014).
Received 20. 10. 2014
ISSN 0556-171X. Ïðîáëåìû ïðî÷íîñòè, 2015, ¹ 1 239
Nonlinearity of the Rock Joint Shear Strength
|