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Appl. Sci. 2018, 8(4), 498; doi:10.3390/app8040498

Rock Fragmentation Characteristics by TBM Cutting and Efficiency under Bi-Lateral Confinement

1,* and 2,3,*
1
State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China
2
Department of Energy and Mineral Engineering, EMS Energy Institute and G3 Center, Pennsylvania State University, University Park, PA 16802, USA
3
Key Laboratory of Hydraulic and Waterway Engineering of the Ministry of Education, Chongqing Jiaotong University, Chongqing 400074, China
*
Authors to whom correspondence should be addressed.
Received: 12 February 2018 / Revised: 13 March 2018 / Accepted: 13 March 2018 / Published: 26 March 2018
(This article belongs to the Section Mechanical Engineering)
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Abstract

In this study, the mechanisms of rock breakage are assessed using tunnel boring machine (TBM) disc cutters under bi-axial pressure. Sequential indentation tests were conducted on granite specimens using a tri-axial testing platform. The morphology and volume of the fractured surface were measured and analyzed using a three-dimensional surface profilometer. An analysis of rock breaking growth and efficiency was performed as well. When the minor confining pressure (σ1) is constant, the results show that a larger difference in confining pressure leads to a larger volume of fractured surface, thereafter improving the rock-breaking efficiency even though the penetration energy is enlarged. On the other hand, when the major confining pressure (σ2) is constant, the penetration energy increases proportionally with the σ1; however, the volume of fractured surface is decreased, and the breaking efficiency is attenuated as well. View Full-Text
Keywords: bi-lateral confinement; TBM disc cutters; rock fragmentation characteristics; morphology of fractured surface bi-lateral confinement; TBM disc cutters; rock fragmentation characteristics; morphology of fractured surface
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Chen, Y.; Song, C. Rock Fragmentation Characteristics by TBM Cutting and Efficiency under Bi-Lateral Confinement. Appl. Sci. 2018, 8, 498.

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