论完整岩体的现场强度

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Abstract It is widely accepted that the field or in-situ strength of massive rocks is approximately (0.4?0.1)?c，where ?c is the uniaxial compressive strength obtained from unconfined laboratory tests. In addition，it has been suggested that the in-situ rock spalling strength，i.e. the strength of the wall of an excavation when spalling initiates，can be set to the crack initiation stress determined from laboratory test or field microseismic monitoring. These findings were based on either Kirsch?s solution or simplified numerical stress modeling(with smooth tunnel wall boundary) to approximate the maximum tangential stress ?max at the excavation boundary. In this article，it is suggested that these approaches ignore one of the most important factors，the irregularity of the excavation boundary. It is demonstrated that the“actual”in-situ spalling strength of massive rocks is not equal to (0.4?0.1)?c，but can be as high as (0.8?0.05)?c when surface irregularities are considered. It is demonstrated using the Mine-by tunnel notch breakout example that when the realistic“as-built”excavation boundary condition is honored，the “actual”in-situ rock mass strength，given by 0.8 ?c，can be applied to simulate progressive brittle rock failure process satisfactorily. We conclude that the interpreted，reduced in-situ rock mass strength of (0.4?0.1)?c without considering geometry irregularity is therefore only an“apparent”rock mass strength.

Key words： rock mechanics rock strength apparent rock mass strength actual rock mass strength crack initiation spalling failure irregular excavation boundary brittle rock

Received: 13 March 2013

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[1] HOEK E，CARRANZA-TORRES C，CORKUM B. Hoek-Brown failure criterion[C]// Proceedings of the Fifth North American Rock Mechanics Symposium. Toronto：Toronto University Press，2002：267–273. [2] CAI M，KAISER P K，UNO H，et al. Estimation of rock mass deformation modulus and strength of jointed hard rock masses using the GSI system[J]. International Journal of Rock Mechanics and Mining Sciences，2004，41(1)：3–19. [3] CAI M，KAISER P K，TASAKA Y，et al. Determination of residual strength parameters of jointed rock masses using the GSI system[J]. International Journal of Rock Mechanics and Mining Sciences，2007，44(2)：247–265. [4] MARTIN C D. Seventeenth Canadian Geotechnical Colloquium：the effect of cohesion loss and stress path on brittle rock strength[J]. Canadian Geotechnical Journal，1997，34(5)：698–725. [5] MARTIN C D. Strength of massive Lac du Bonnet granite around underground openings[Ph. D. Thesis][D]. Manitoba：University of Manitoba，1993. [6] READ R S，CHANDLER N A，DZIK E J. In-situ strength criteria for tunnel design in highly-stressed rock masses[J]. International Journal of Rock Mechanics and Mining Sciences，1998，35(3)：261–278. [7] MARTIN C D，KAISER P K，MCCREATH D R. Hoek-Brown parameters for predicting the depth of brittle failure around tunnels[J]. Canadian Geotechnical Journal，1999，36 (1)：136–151. [8] ANDERSSON J C，MARTIN C D，STILLE H. The Äspö pillar stability experiment：part II–rock mass response to coupled excavation-induced and thermal-induced stresses[J]. International Journal of Rock Mechanics and Mining Sciences，2009，46(5)：879–895. [9] BRACE W F，PAULDING B W，SCHOLZ C H. Dilatancy in the fracture of crystalline rocks[J]. Journal of Geophysical Research，1966，71(16)：3 939–3 953. [10] BIENIAWSKI Z T. Mechanism of brittle fracture of rock，parts I，II and III[J]. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts，1967，4(4)：395–430. [11] MARTIN C D，CHANDLER N A. The progressive fracture of Lac du Bonnet granite[J]. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts，1994，31(6)：643–659. [12] LAJTAI E Z，LAJTAI V N. The evolution of brittle fracture in rocks[J]. Journal of the Geological Society of London，1974，130(1)：1–16. [13] EBERHARDT E，STEAD D，STIMPSON B，et al. Identifying crack initiation and propagation thresholds in brittle rock[J]. Canadian Geotechnical Journal，1998，35(2)：222–233. [14] CAI M，KAISER P K，TASAKA Y，et al. Generalized crack initiation and crack damage stress thresholds of brittle rock masses near underground excavations[J]. International Journal of Rock Mechanics and Mining Sciences，2004，41(5)：833–847. [15] EMSLEY S，OLSSON O，STENBERG L，et al. ZEDEX-A study of damage and disturbance from tunnel excavation by blasting and tunnel boring[R]. Stockholm：Swedish Nuclear Fuel and Waste Management Co.，1997. [16] MOGI K. The influence of the dimensions of specimens on the fracture strength of rocks[J]. Bulletin of the Earthquake Research Institute，1962，40(1)：175–185. [17] PRATT H R，BLACK A D，BROWN W S，et al. The effect of specimen size on the mechanical properties of unjointed diorite[J]. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts，1972，9(4)：513–516. [18] HOEK E，BROWN E T. Underground excavations in rock[M]. London：Institution of Mining and Metallurgy，1980：527. [19] GOODMAN R E. Introduction to rock mechanics[M]. New York： John Wiley and Sons，1989：90. [20] CARTER B J. Size and stress gradient effects on fracture around cavities[J]. Rock Mechanics and Rock Engineering，1992，25(3)：167–186. [21] LOCKNER D A. Rock failure[M]. Rock Physics and Phase Relations： A Handbook of Physical Constants. Washington D C：American Geophysical Union，1995：27–147. [22] JACKSON R，LAU J S O. The effect of specimen size on the laboratory mechanical properties of Lac du Bonnet grey granite[C]// Proceedings of the First International Workshop on Scale Effects in Rock Masses. Rotterdam：A. A. Balkema，1990：165–174. [23] HOEK E. Rock fracture under static stress conditions[R]. Pretoria：Council for Scientific and Industrial Research，1965. [24] EWY R T，COOK N G W. Deformation and fracture around cylindrical openings in rock–I，observations and analysis of deformations[J]. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts，1990，27(5)：387–407. [25] MARTIN C D，MARTINO J B，DZIK E J. Comparison of borehole breakouts from laboratory and field tests[C]// Proceedings of the Eurock′94. Rotterdam：A. A. Balkema，1994：183–190. [26] STACEY T R. A simple extension strain criterion for fracture of brittle rock[J]. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts，1981，18(6)：469–474. [27] MYRVANG A M. Estimation of in situ compressive strength of rocks from in situ stress measurements in highly stressed rock structures[C]// Proceedings of the 7th ISRM Congress. Rotterdam. A. A. Balkema，1991：573–575. [28] PELLI F，KAISER P K，MORGENSTERN N R. An interpretation of ground movements recorded during construction of the Donkin- Morien tunnel[J]. Canadian Geotechnical Journal，1991，28(2)：239–254. [29] MARTIN C D. Brittle rock strength and failure：Laboratory and in situ[C]// Proceedings of the 8th ISRM Congress. Rotterdam：A. A. Balkema，1995：1 033–1 040. [30] WISEMAN N. Factors affecting the design and condition of mine tunnels[R]. Pretoria：Chamber of Mines of South Africa，1979. [31] DIEDERICHS M S. The 2003 Canadian Geotechnical Colloquium：mechanistic interpretation and practical application of damage and spalling prediction criteria for deep tunneling[J]. Canadian Geotechnical Journal，2007，44(9)：1 082–1 116. [32] KAISER P K，DIEDERICHS M S，MARTIN C D，et al. Underground works in hard rock tunnelling and mining[C]// Proceedings of GeoEng2000. Melbourne：Australia Technomic Publishing Co.，2000：841–926. [33] KAISER P K，YAZICI S，MALONEY S. Mining-induced stress change and consequences of stress path on excavation stability—a case study[J]. International Journal of Rock Mechanics and Mining Sciences，2001，38(2) ：167–180. [34] CAI M，KAISER P K，UNO H，et al. Influence of stress-path on the stress-strain relations of jointed rocks[C]// Proceedings of the Second International Conference on New Development in Rock Mechanics and Rock Engineering. Princeton：Rinton Press，2002：60–65. [35] CAI M. Influence of stress path on tunnel excavation response——numerical tool selection and modeling strategy[J]. Tunnelling and Underground Space Technology，2008，23(6)：618–628. [36] KAISER P K，MCCREATH D R，TANNANT D D. Canadian rockburst support handbook[M]. Sudbury：CAMIRO，1996：10. [37] HOEK E，KAISER P K，BAWDEN W F. Support of underground excavations in hard rock[M]. Rotterdam A. A. Balkema，1995：100. [38] 王明年，关宝树. 隧道超挖对围岩内应力状态的影响[J]. 铁道学报，1997，19(2)：86–90.(WANG Mingnian，GUAN Baoshu. Tunnel overbreak influence on stress state of surrounding rock[J]. Journal of the China Railway Society，1997，19(2)：86–90.(in Chinese)) [39] HAJIABDOLMAJID V，KAISER P K，MARTIN C D. Modelling brittle failure of rock[C]// Proceedings of the 4th North American Rock Mechanics Symposium. Rotterdam：A. A. Balkema，2000：991–998. [40] STACEY T R，YATHAVAN K. Examples of fracturing of rock at very low stress levels[C]// Proceedings of the 10th ISRM Congress —Technology Roadmap for Rock Mechanics. Johannesburg：SAIMM，2003：1 155–1 159. [41] KAISER P K，KIM B H，BEWICK R P，et al. Rock mass strength at depth and implications for pillar design[J]. Mining Technology，2011，120(3)：170–179. [42] CAI M. Practical estimates of tensile strength and Hoek-Brown strength parameter mi of brittle rocks[J]. Rock Mechanics and Rock Engineering，2010，43(2)：167–184.