Fracturing of ice under compression creep as revealed by a multifractal analysis

Fracturing of freshwater granular ice up to failure under uniaxial compression creep was investigated from series of interrupted creep tests and from a multifractal analysis of the corresponding fracture patterns. At the early stages of damage corresponding to primary and secondary creep, the fracturing process is dominated by the nucleation of microcracks from stress concentrations within the material (unlike rocks, artificial freshwater ice does not contains starter flaws). Because of the crack nucleation mechanisms, the microstructure of the material (e.g., the nonfractal grain size distribution) strongly influences the organization of fracturing which is therefore nonfractal. As fracturing proceeds during tertiary creep, a hierarchical (fractal) organization of the fracturing emerges progressively over a wider scale range. At failure, this fractal organization is fully developed without detectable lower or upper bound, and the role of the initial microstructure has completely disappeared. Similarly, cracks are preferentially oriented along the compression axis at the early stages of damage, but this anisotropy vanishes as failure is approached. The simultaneity between the onset of tertiary creep and the emergence of fractal organization suggests that the acceleration of the deformation during tertiary creep is due to the cataclasis of a material which becomes granular. An important consequence of the fractal organization of fracturing is that homogenization procedures, as well as damage mechanics, developed to study the behavior of damaged materials, cannot be used to describe tertiary creep and failure.

[1]  A. Provost,et al.  Scaling rules in rock fracture and possible implications for earthquake prediction , 1982, Nature.

[2]  H. G. E. Hentschel,et al.  The infinite number of generalized dimensions of fractals and strange attractors , 1983 .

[3]  M. F. Ashby,et al.  Rate-controlling processes in the creep of polycrystalline ice , 1983 .

[4]  Mitsugu Matsushita,et al.  Fractal Viewpoint of Fracture and Accretion , 1985 .

[5]  Christopher C. Barton,et al.  Fractal geometry of two-dimensional fracture networks at Yucca Mountain, southwestern Nevada: proceedings , 1985 .

[6]  S. D. Hallam,et al.  The failure of brittle solids containing small cracks under compressive stress states , 1986 .

[7]  D. Cole.  Effect of Grain Size on the Internal Fracturing of Polycrystalline Ice , 1986 .

[8]  Donald L. Turcotte,et al.  Fractals and fragmentation , 1986 .

[9]  Ronald L. Biegel,et al.  The kinematics of gouge deformation , 1987 .

[10]  Keisuke Ito,et al.  Fractal structure of spatial distribution of microfracturing in rock , 1987 .

[11]  S. D. Hallam,et al.  A STUDY OF CRACKS IN POLYCRYSTALLINE ICE UNDER UNIAXIAL COMPRESSION , 1987 .

[12]  E. Schulson,et al.  The brittle compressive fracture of ice , 1990 .

[13]  D. Sornette,et al.  Some consequences of a proposed fractal nature of continental faulting , 1990, Nature.

[14]  Xinglin Lei,et al.  Effect of grain size on fractal structure of acoustic emission hypocenter distribution in granitic rock , 1991 .

[15]  D. Turcotte.  Fractals and Chaos in Geology and Geophysics , 1992 .

[16]  G. King,et al.  The mechanisms of finite brittle strain , 1992 .

[17]  Gabor Korvin,et al.  Fractal models in the earth sciences , 1992 .

[18]  B. Velde,et al.  Fractal and length analysis of fractures during brittle to ductile changes , 1993 .

[19]  O. Nishizawa,et al.  Band‐limited heterogeneous fractal structure of earthquakes and acoustic‐emission events , 1993 .

[20]  E. Schulson,et al.  The failure of fresh-water granular ice under multiaxial compressive loading , 1995 .

[21]  Didier Sornette,et al.  Multifractal scaling properties of a growing fault population , 1995 .

[22]  E. Schulson,et al.  Failure of columnar saline ice under biaxial compression: Failure envelopes and the brittle‐to‐ductile transition , 1995 .

[23]  J. FrostH.  Mechanisms of crack nucleation in ice. , 1995 .

[24]  D. Sanderson,et al.  Sampling power-law distributions , 1995 .

[25]  J. grasso,et al.  Hierarchical organization as a diagnostic approach to volcano mechanics: Validation on Piton de la Fournaise , 1995 .

[26]  Ian G. Main,et al.  Statistical physics, seismogenesis, and seismic hazard , 1996 .

[27]  D. Sornette,et al.  Unbiased multifractal analysis: Application to fault patterns , 1996 .

[28]  Ian Jordaan,et al.  Application of damage mechanics to ice failure in compression , 1996 .

[29]  E. Schulson,et al.  The nucleation of microcracks in ice cubes compressed equally on all boundaries , 1996 .

[30]  D. Sornette,et al.  Hierarchical geometry of faulting , 1996 .

[31]  D. Sornette,et al.  The Imaginary Part of Rock Jointing , 1996 .

[32]  J. Weiss,et al.  Microcrack Nucleation in Different Kinds of Artificial Ice during Uniaxial Compression Creep Experiments , 1996 .

[33]  E. Schulson,et al.  The Brittle Failure of Ice under Compression , 1997 .