Mechanical properties of abandoned and closed roadways in the Kushiro Coal Mine, Japan

Fujii, Yoshiyuki; Ishijima, Yoji; Ichihara, Yoshihisa; Kiyama, Tamotsu; Kumakura, Satoshi; Takada, Makoto; Sugawara, T.; Narita, Takashi; Kodama, Junichi; Sawada, Masataka; Nakata, Eiji

doi:10.1016/j.ijrmms.2011.04.012

Cited by 26 publications

(17 citation statements)

References 1 publication

(3 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the influence of the humidity on the fracture toughness of rock has yet to be fully explored. Fujii et al (2011) reported that several large rock falls occurred in humid summer in Kushiro Coal Mine in Japan due to the weakening of rock by inflow of humid air. This report suggests that the investigation of the humidity effects on fracture toughness of rock is important for ensuring the stability of structures in a rock mass.…”

Section: Introductionmentioning

confidence: 99%

Influence of relative humidity on fracture toughness of rock: Implications for subcritical crack growth

Nara

Morimoto

Hiroyoshi

et al. 2012

International Journal of Solids and Structures

154

View full text Add to dashboard Cite

a b s t r a c tInformation relating to the fracture toughness of geomaterials is critical to our understanding of tensile fracturing, and in particular in geological and rock engineering projects that are subjected to elevated moisture levels. In this study, we conducted a comprehensive set of fracture toughness tests on a suite of key rock types in air under different relative humidities and at constant temperature in order to investigate the influence of relative humidity on fracture toughness. Three sandstones and two igneous rocks were chosen for this purpose. We show that the value of fracture toughness decreases with increasing relative humidity. In addition, we find that the decrease in fracture toughness was more significant when the expansive clay such as smectite was included in rock. Since smectite is prone to expanding in the presence of water, the strength and thus crack growth resistance decrease when relative humidity is high. Therefore, we interpret the decreasing fracture toughness upon the degradation of expansive clays with increasing water content. It was also shown that the decrease of the fracture toughness with increasing humidity is less significant than the concomitant decrease in the measured value of the subcritical stress intensity factor. This was likely as a result of stress corrosion having little influence on the fracture toughness. We conclude that crack growth in rock is affected by humidity, and that clay content is an important contributing factor to changes in fracture toughness and subcritical stress intensity factor.

show abstract

Section: Introductionmentioning

confidence: 99%

Influence of relative humidity on fracture toughness of rock: Implications for subcritical crack growth

Nara

Morimoto

Hiroyoshi

et al. 2012

International Journal of Solids and Structures

154

View full text Add to dashboard Cite

show abstract

“…29 As described in Section 1, in the Kushiro Coal Mine, rock falls often happen when humidity is high. 7 When a decrease in P-wave velocity in a rock mass is observed to coincide with an increase of humidity, failure from the surface of the rock mass may well be imminent. The results of this study offer fundamental information concerning the weakening of a rock mass structure.…”

Section: Discussionmentioning

confidence: 99%

“…6 Humidity is known to affect strength and fracturing in rock. For example, Fujii et al 7 reported that the strength of sandstone in Kushiro Coal Mine in Japan (Kushiro sandstone) decreases as water content rises. According to, 7 rock fall is common in a mining gallery in Kushiro Coal Mine during summer when the relative humidity is high.…”

Section: Introductionmentioning

confidence: 99%

P-wave propagation in dry rocks under controlled temperature and humidity

Nakao

Nara

Kubo

2016

International Journal of Rock Mechanics and Mining Sciences

View full text Add to dashboard Cite

“…The former are zones of mainly elastic disturbance whereas the latter are zones that have irrecoverable damage [Tsang et al, 2005]. Stress redistribution and permeability changes within these zones [Sato et al, 2000;Fujii et al, 2011;Tsang et al, 2005] can affect the sealability. This represents the tightness of an opening and is defined as inversely proportional to the flow velocity per unit pore pressure gradient of the surrounding rock mass, due to hydromechanical (HM) coupling.…”

Section: Introductionmentioning

confidence: 99%

Fractured Rock Permeability as a Function of Temperature and Confining Pressure

Alam

Fujii

Fukuda

et al. 2015

Pure Appl. Geophys.

Self Cite

View full text Add to dashboard Cite

Triaxial compression tests were carried out on Shikotsu welded tuff, Kimachi sandstone, and Inada granite under confining pressures of 1-15 MPa at 295 K and 353 K. The permeability of the tuff declined monotonically with axial compression. The post-compression permeability became smaller than that before axial compression.The permeability of Kimachi sandstone and Inada granite declined at first, and then 2 began to increase before the peak load, and showed values that were almost constant in the residual strength state. The post-compression permeability of Kimachi sandstone was higher than that before axial compression under low confining pressures, but lower under higher confining pressures. On the other hand, the permeability of Inada granite was higher than that before axial compression regardless of the confining pressure values. For the all rock types, the post-compression permeability at 353 K was lower than at 295 K and the influence of the confining pressure was less at 353 K than at 295 K. The above temperature effects were observed apparently for Inada granite, only the latter effect was apparent for Shikotsu welded tuff, and they were not so obvious for Kimachi sandstone. The mechanisms causing the variation in rock permeability, and sealability of underground openings were discussed. Key Points:The influence of confining pressure on permeability is less at 353 K than at 295 K.The flow speed at 353 K is nearly the same as at 295 K or significantly slower.Pore collapse, and plastic and viscous deformation are dominant mechanisms.

show abstract

Mechanical properties of abandoned and closed roadways in the Kushiro Coal Mine, Japan

Abstract: The objective of this research is to clarify the mechanical properties and self-healing ability of ExcavationDamaged Zone (EDZ)

Cited by 26 publications

References 1 publication

Influence of relative humidity on fracture toughness of rock: Implications for subcritical crack growth

Influence of relative humidity on fracture toughness of rock: Implications for subcritical crack growth

P-wave propagation in dry rocks under controlled temperature and humidity

Fractured Rock Permeability as a Function of Temperature and Confining Pressure

Contact Info

Product

Resources

About