Estimating in-situ rock stress from spalling veins: A case study

Stress-induced failures have typically been considered as engineering disasters in deep underground excavations. This paper highlights the importance of stress-driven rock failures as a means to estimate the in-situ rock stress at the depth. The method, which is based on the observation and documentation of a failure mode referred to here as “spalling” in deep tunnels or caverns, is put forward and presented to estimate the macro-scale rock stress. Using the proposed method, the orientation of the principal stresses in-situ can be deduced by the spalling intensity and associated stress-induced spalling veins in the rock mass surrounding the opening, and the magnitude of the principal stresses can be estimated by the assumed crack initiation stress required to generate spalling in the given rock by careful documentation of spalling failure characteristic in the field. A real case study at Baihetan powerhouse site has been carried out and indicates that the proposed method is an available way to enriching recognition of in-situ rock stress and a helpful supplement to traditional methods of stress measurements after strictly numerical verification. Analysis of the regional tectonic setting as well as measurements of in-situ stress supports the results by the suggested approach.

[1]  John A. Hudson,et al.  Quality control of overcoring stress measurement data , 2003 .

[2]  E. Hoek,et al.  Empirical estimation of rock mass modulus , 2006 .

[3]  N. Cook,et al.  THE FAILURE OF ROCK , 1965 .

[4]  M. Zoback,et al.  Determination of stress orientation and magnitude in deep wells , 2003 .

[5]  G. E. Exadaktylos,et al.  Pillar failure by axial splitting in brittle rocks , 1995 .

[6]  John A. Hudson,et al.  ISRM Suggested Methods for rock stress estimation—Part 2: overcoring methods , 2003 .

[7]  F. Cornet,et al.  ISRM Suggested Methods for rock stress estimation; Part 3, Hydraulic fracturing (HF) and/ or hydraulic testing of pre-existing fractures (HTPF) , 2003 .

[8]  P. K. Kaiser,et al.  Hoek-Brown parameters for predicting the depth of brittle failure around tunnels , 1999 .

[9]  Mark D. Zoback,et al.  In-situ stress orientation and magnitude at the Fenton Geothermal Site, New Mexico, determined from , 1988 .

[10]  Naser A. Al-Shayea,et al.  Crack propagation trajectories for rocks under mixed mode I–II fracture , 2005 .

[11]  C D Martin,et al.  Seven years of in situ stress measurements at the URL; an overview , 1990 .

[12]  R. Kranz,et al.  Crack-crack and crack-pore interactions in stressed granite , 1979 .

[13]  Xia-Ting Feng,et al.  Rockburst characteristics and numerical simulation based on a new energy index: a case study of a tunnel at 2,500 m depth , 2010 .

[14]  Erling Nordlund,et al.  Experimental verification of the Kaiser effect in rocks , 1993 .

[15]  Bernard Amadei,et al.  Rock stress and its measurement , 1997 .

[16]  B. A. Leijon.  Relevance of pointwise rock stress measurements—an analysis of overcoring data , 1989 .

[17]  G. W. Lanyon,et al.  Measurement of in-situ stress in weak rocks at Mont Terri Rock Laboratory, Switzerland , 2003 .

[18]  Ming Cai,et al.  Generalized crack initiation and crack damage stress thresholds of brittle rock masses near underground excavations , 2004 .

[19]  R. S. Read,et al.  20 years of excavation response studies at AECL's Underground Research Laboratory , 2004 .

[20]  Teng-fong Wong,et al.  MICROMECHANICS OF FAULTING IN WESTERLY GRANITE , 1982 .

[21]  B. Sinha,et al.  Predicting rock failure around boreholes and drives adjacent to stopes in Indian mines in high stress regions , 2002 .

[22]  B. Haimson.  Borehole Breakouts in Berea Sandstone Reveal a New Fracture Mechanism , 2003, Pure and Applied Geophysics.

[23]  Texture, mineralogy, and rock strength in horizontal stress-related coal mine roof falls , 2008 .

[24]  T. Hijazo,et al.  A new method of estimating the ratio between in situ rock stresses and tectonics based on empirical and probabilistic analyses , 2008 .

[25]  M. Cai,et al.  Considerations of rock dilation on modeling failure and deformation of hard rocks—a case study of the mine-by test tunnel in Canada , 2010 .

[26]  Paul Tapponnier,et al.  Development of stress-induced microcracks in Westerly Granite , 1976 .

[27]  Peter K. Kaiser,et al.  Numerical simulation of cumulative damage and seismic energy release during brittle rock failure-Part I: Fundamentals , 1998 .

[28]  C. D. Martin,et al.  Estimating the potential for spalling around a deep nuclear waste repository in crystalline rock , 2009 .

[29]  Mark S. Diederichs,et al.  Damage initiation and propagation in hard rock during tunnelling and the influence of near-face stress rotation , 2004 .

[30]  V. Palchik,et al.  The influence of grain size and porosity on crack initiation stress and critical flaw length in dolomites , 1997 .

[31]  P. K. Kaiser,et al.  Support of underground excavations in hard rock , 1995 .

[32]  M. Zoback,et al.  Stress orientation profile to 3.5 km depth near the San Andreas Fault at Cajon Pass, California , 1992 .

[33]  S. Nemat-Nasser,et al.  Brittle failure in compression: splitting faulting and brittle-ductile transition , 1986, Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences.

[34]  Y. Obara,et al.  Rock stress interpretations from Mt. Torigata (Japan) based on calcite strain gauge and differential strain curve analysis , 2000 .