### Abstract

The stability of structures that are built over rock is affected by cracks in the rock that result from weathering, thawing and freezing processes. This study investigates a new method for determining rock crack densities using elastic wave velocities. The Biot-Gassmann model, which consists of several elastic moduli and Poisson's ratio, was used to determine a theoretical equation to predict the crack density of rocks. Ten representative specimens were extracted from ten boreholes to highlight the spatial variability. Each specimen was characterized using X-Ray Diffraction (XRD) analysis. The specimens were carved into cylinders measuring 50. mm in diameter and 30. mm in height using an abrasion process. A laboratory test was performed to obtain the elastic wave velocity using transducers that can transmit and receive compressional and shear waves. The measured compressional wave and shear wave velocities were approximately 2955. m/s-5209. m/s and 1652. m/s-2845. m/s, respectively. From the measured elastic wave velocities, the analyzed crack density and crack porosity were approximately 0.051-0.185 and 0.03%-0.14%, respectively. The calculated values were compared with the results of previous studies, and they exhibit similar values and trends. The sensitivity of the suggested theoretical equation was analyzed using the error norm technique. The results show that the compressional wave velocity and the shear modulus of a particle are the most influential factors in this equation. The study demonstrates that rock crack density can be estimated using the elastic wave velocities, which may be useful for investigating the stability of structures that are built over rock.

Original language | English |
---|---|

Pages (from-to) | 110-119 |

Number of pages | 10 |

Journal | Journal of Applied Geophysics |

Volume | 115 |

DOIs | |

Publication status | Published - 2015 Apr 1 |

### Fingerprint

### Keywords

- Biot-Gassmann model
- Crack density
- Elastic waves
- Porosity
- Rock specimen
- Stability

### ASJC Scopus subject areas

- Geophysics

### Cite this

*Journal of Applied Geophysics*,

*115*, 110-119. https://doi.org/10.1016/j.jappgeo.2015.02.020

**Prediction of crack density in porous-cracked rocks from elastic wave velocities.** / Byun, Ji Hwan; Lee, Jong-Sub; Park, Keunbo; Yoon, Hyung Koo.

Research output: Contribution to journal › Article

*Journal of Applied Geophysics*, vol. 115, pp. 110-119. https://doi.org/10.1016/j.jappgeo.2015.02.020

}

TY - JOUR

T1 - Prediction of crack density in porous-cracked rocks from elastic wave velocities

AU - Byun, Ji Hwan

AU - Lee, Jong-Sub

AU - Park, Keunbo

AU - Yoon, Hyung Koo

PY - 2015/4/1

Y1 - 2015/4/1

N2 - The stability of structures that are built over rock is affected by cracks in the rock that result from weathering, thawing and freezing processes. This study investigates a new method for determining rock crack densities using elastic wave velocities. The Biot-Gassmann model, which consists of several elastic moduli and Poisson's ratio, was used to determine a theoretical equation to predict the crack density of rocks. Ten representative specimens were extracted from ten boreholes to highlight the spatial variability. Each specimen was characterized using X-Ray Diffraction (XRD) analysis. The specimens were carved into cylinders measuring 50. mm in diameter and 30. mm in height using an abrasion process. A laboratory test was performed to obtain the elastic wave velocity using transducers that can transmit and receive compressional and shear waves. The measured compressional wave and shear wave velocities were approximately 2955. m/s-5209. m/s and 1652. m/s-2845. m/s, respectively. From the measured elastic wave velocities, the analyzed crack density and crack porosity were approximately 0.051-0.185 and 0.03%-0.14%, respectively. The calculated values were compared with the results of previous studies, and they exhibit similar values and trends. The sensitivity of the suggested theoretical equation was analyzed using the error norm technique. The results show that the compressional wave velocity and the shear modulus of a particle are the most influential factors in this equation. The study demonstrates that rock crack density can be estimated using the elastic wave velocities, which may be useful for investigating the stability of structures that are built over rock.

AB - The stability of structures that are built over rock is affected by cracks in the rock that result from weathering, thawing and freezing processes. This study investigates a new method for determining rock crack densities using elastic wave velocities. The Biot-Gassmann model, which consists of several elastic moduli and Poisson's ratio, was used to determine a theoretical equation to predict the crack density of rocks. Ten representative specimens were extracted from ten boreholes to highlight the spatial variability. Each specimen was characterized using X-Ray Diffraction (XRD) analysis. The specimens were carved into cylinders measuring 50. mm in diameter and 30. mm in height using an abrasion process. A laboratory test was performed to obtain the elastic wave velocity using transducers that can transmit and receive compressional and shear waves. The measured compressional wave and shear wave velocities were approximately 2955. m/s-5209. m/s and 1652. m/s-2845. m/s, respectively. From the measured elastic wave velocities, the analyzed crack density and crack porosity were approximately 0.051-0.185 and 0.03%-0.14%, respectively. The calculated values were compared with the results of previous studies, and they exhibit similar values and trends. The sensitivity of the suggested theoretical equation was analyzed using the error norm technique. The results show that the compressional wave velocity and the shear modulus of a particle are the most influential factors in this equation. The study demonstrates that rock crack density can be estimated using the elastic wave velocities, which may be useful for investigating the stability of structures that are built over rock.

KW - Biot-Gassmann model

KW - Crack density

KW - Elastic waves

KW - Porosity

KW - Rock specimen

KW - Stability

UR - http://www.scopus.com/inward/record.url?scp=84923348749&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84923348749&partnerID=8YFLogxK

U2 - 10.1016/j.jappgeo.2015.02.020

DO - 10.1016/j.jappgeo.2015.02.020

M3 - Article

VL - 115

SP - 110

EP - 119

JO - Journal of Applied Geophysics

JF - Journal of Applied Geophysics

SN - 0926-9851

ER -