Active Seismic Monitoring of Crack Initiation, Propagation, and Coalescence in Rock

Active seismic monitoring was used to detect and characterize crack initiation, crack propagation and crack coalescence in pre-cracked rock specimens. Uniaxial compression tests were conducted on Indiana limestone specimens with two parallel pre-existing cracks. During the experiments, the mechanically induced cracks around the flaw tips were monitored by measuring surface displacements using digital image correlation (DIC). Transmitted and reflected compressional and shear waves through the specimens were also recorded during the loading to detect any damage or cracking phenomena. The amplitude of transmitted compressional and shear waves decreased with uniaxial compression. However, the rate of decrease of the amplitude of the transmitted waves intensified well before the initiation of tensile cracks. In addition, a distinct minimum in the amplitude of transmitted waves occurred close to coalescence. The normalized amplitude of waves reflecting from the new cracks increased before new tensile and shear cracks initiated around the flaw tips. In addition, the location of new cracks could be identified using the traveling time of the reflected waves. The experimental results indicate that changes in normalized amplitude of transmitted and reflected signals associated with crack initiation and crack coalescence were detected much earlier than with DIC, at a load of about 80–90% of the load at which the cracks appeared on the surface. The tests show conclusively that active wave monitoring is an effective tool to detect damage and new cracks in rock, as well as to estimate the location of the new cracks.

[1]  Louis Ngai Yuen Wong,et al.  Fracturing Behavior of Prismatic Specimens Containing Single Flaws , 2006 .

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

[3]  Satoru Yoneyama,et al.  DIGITAL IMAGE CORRELATION , 2011 .

[4]  W. F. Ranson,et al.  Applications of digital-image-correlation techniques to experimental mechanics , 1985 .

[5]  A. Bobet,et al.  Coalescence of Multiple Flaws in Uniaxial Compression , 2000 .

[6]  Joseph F Labuz,et al.  Opening and mixed mode fracture processes in a quasi-brittle material via digital imaging , 2014 .

[7]  Antonio Bobet,et al.  Crack coalescence in specimens with open and closed flaws: A comparison , 2009 .

[8]  E. Hoek,et al.  Fracture initiation and propagation in intact rock – A review , 2014 .

[9]  K. T. Chau,et al.  Analysis of crack coalescence in rock-like materials containing three flaws—Part I: experimental approach , 2001 .

[10]  A. Bobet,et al.  Detection and Quantification of Slip Along Non-Uniform Frictional Discontinuities Using Digital Image Correlation , 2014 .

[11]  Anand Asundi,et al.  Two-dimensional digital image correlation for in-plane displacement and strain measurement: a review , 2009 .

[12]  K. T. Chau,et al.  Crack coalescence in a rock-like material containing two cracks , 1998 .

[13]  Herbert H. Einstein,et al.  Fracture coalescence in rock-type materials under uniaxial and biaxial compression , 1998 .

[14]  Gioacchino Viggiani,et al.  Fracture mechanisms in soft rock: Identification and quantification of evolving displacement discontinuities by extended digital image correlation , 2011 .

[15]  Joseph F Labuz,et al.  Fracture of sandstone characterized by digital image correlation , 2013 .

[16]  D. Lockner.  The role of acoustic emission in the study of rock fracture , 1993 .

[17]  L. Wong,et al.  Crack Coalescence in Molded Gypsum and Carrara Marble: Part 1. Macroscopic Observations and Interpretation , 2009 .

[18]  L. Pyrak‐Nolte,et al.  Interface waves along fractures in anisotropic media , 2013 .

[19]  Eurípedes do Amaral Vargas,et al.  Application of the discrete element method for modeling of rock crack propagation and coalescence in the step-path failure mechanism , 2013 .

[20]  B. Stimpson,et al.  Identifying crack initiation and propagation thresholds in brittle rock , 1998 .

[21]  Shaowei Hu,et al.  Evaluation of concrete fracture procedure based on acoustic emission parameters , 2013 .

[22]  N. Cook,et al.  Transmission of seismic waves across single natural fractures , 1990 .

[23]  W. A. Take,et al.  Soil deformation measurement using particle image velocimetry (PIV) and photogrammetry , 2003 .

[24]  J. Réthoré,et al.  Identification of damage and cracking behaviours based on energy dissipation mode analysis in a quasi-brittle material using digital image correlation , 2011 .

[25]  G. Dresen,et al.  Fracture process zone in granite: a microstructural analysis , 2001 .

[26]  Ariel R. Martinez,et al.  Fracture coalescence in natural rocks , 1999 .

[27]  Giovanni Leucci,et al.  Experimental studies on the effects of fracture on the P and S wave velocity propagation in sedimentary rock (“Calcarenite del Salento”) , 2006 .

[28]  Sia Nemat-Nasser,et al.  Compression‐induced microcrack growth in brittle solids: Axial splitting and shear failure , 1985 .

[29]  S. Roux,et al.  Digital image correlation and fracture: an advanced technique for estimating stress intensity factors of 2D and 3D cracks , 2009 .

[30]  Herbert H. Einstein,et al.  Coalescence of fractures under shear stresses in experiments , 1995 .

[31]  Herbert H. Einstein,et al.  Crack coalescence in brittle material under cyclic loading , 2006 .

[32]  A. Asundi,et al.  Digital image correlation using iterative least squares and pointwise least squares for displacement field and strain field measurements , 2009 .

[33]  Huang Jiefan,et al.  An experimental study of the strain field development prior to failure of a marble plate under compression , 1990 .

[34]  Sheng-Qi Yang,et al.  Strength failure and crack coalescence behavior of brittle sandstone samples containing a single fissure under uniaxial compression , 2011 .

[35]  B. J. Carter,et al.  Criteria for brittle fracture in compression , 1990 .

[36]  Laura J. Pyrak-Nolte,et al.  The seismic response of fractures and the interrelations among fracture properties , 1996 .

[37]  K. Otsuka,et al.  Fracture process zone in concrete tension specimen , 2000 .

[38]  Georg Dresen,et al.  Tensile fracture propagation and acoustic emission activity in sandstone: The effect of loading rate , 2005 .

[39]  Joseph F Labuz,et al.  Measurement of the intrinsic process zone in rock using acoustic emission , 1998 .

[40]  Jean-François Thimus,et al.  The properties of coupling agents in improving ultrasonic transmission , 1996 .

[41]  Antonio Bobet,et al.  Fracture coalescence in rock materials : experimental observations and numerical predictions , 1997 .

[42]  Baotang Shen,et al.  The mechanism of fracture coalescence in compression—experimental study and numerical simulation , 1995 .

[43]  Jean-Pierre Petit,et al.  Can natural faults propagate under Mode II conditions , 1988 .

[44]  L. Pyrak‐Nolte,et al.  Variation of shear-wave amplitude during frictional sliding , 1993 .

[45]  G. Paulino,et al.  Identification of cohesive zone model and elastic parameters of fiber-reinforced cementitious composites using digital image correlation and a hybrid inverse technique , 2011 .

[46]  A. Ingraffea,et al.  FINITE ELEMENT MODELS FOR ROCK FRACTURE MECHANICS , 1980 .

[47]  H. H. Einstein,et al.  Coalescence Behavior In Carrara Marble And Molded Gypsum Containing Artificial Flaw Pairs Under Uniaxial Compression , 2007 .

[48]  Ping Cao,et al.  Crack propagation and coalescence of brittle rock-like specimens with pre-existing cracks in compression , 2015 .

[49]  S. Kahraman.  The effects of fracture roughness on P-wave velocity , 2002 .

[50]  Arcady Dyskin,et al.  Mechanisms of brittle fracture of rock with pre-existing cracks in compression , 1994 .

[51]  Arcady Dyskin,et al.  Influence of shape and locations of initial 3-D cracks on their growth in uniaxial compression , 2003 .

[52]  Jean-José Orteu,et al.  3-D computer vision in experimental mechanics , 2007 .

[53]  J. Byerlee.  A review of rock mechanics studies in the United States pertinent to earthquake prediction , 1978 .

[54]  K. Nihei,et al.  Shear-induced conversion of seismic waves across single fractures , 2000 .

[55]  James R. Clifton,et al.  Fracture process zone , 1986 .

[56]  Yin-Ping Li,et al.  Experimental research on pre-cracked marble under compression , 2005 .

[57]  Fred Kofi Boadu,et al.  Fractured rock mass characterization parameters and seismic properties: Analytical studies , 1997 .

[58]  Louis Ngai Yuen Wong,et al.  Systematic evaluation of cracking behavior in specimens containing single flaws under uniaxial compression , 2009 .

[59]  Joseph F Labuz,et al.  Initiation of tensile and mixed-mode fracture in sandstone , 2009 .

[60]  Hubert W. Schreier,et al.  Image Correlation for Shape, Motion and Deformation Measurements: Basic Concepts,Theory and Applications , 2009 .