The Influence of Confining Stresses on Rock Fragmentation, Thrust Force, and Penetration Energy in Sandstone Indentation Tests Using Disc Cutters

Published on Mar 31, 2021in Advances in Civil Engineering1.924
· DOI :10.1155/2021/5541538
Gaofeng Wang2
Estimated H-index: 2
(CUMT: China University of Mining and Technology),
Ting Ren27
Estimated H-index: 27
(University UCINF),
Gaolei Zhu1
Estimated H-index: 1
(CUMT: China University of Mining and Technology)
Hard rock Tunnel Boring Machines (TBMs) engaging disc cutters as cutting tools have been employed in considerable underground coal mines to accommodate the requirement of more stone drivage as operations are going deeper. This study conducted a set of disc cutter indentation tests to explore the influence of confining stresses on rock fragmentation, thrust force, and penetration energy on sandstone, which is commonly encountered in underground coal mines. The test results show that there exists a critical confining stress, under which the maximum thrust force and penetration energy keep increasing with confining stress mounting while the maximum thrust force and penetration energy will decrease or flatten if it is surpassed. By combining with previous studies and comparing the critical confining stress values to the rock mechanical properties’ values, the critical value is most likely to be of cohesion. For subsurface rock fragmentation, the Constant Cross Section (CCS) disc cutter indentation has denser cracks and their orientations are more lateral than those under the V shape one; the V shape disc cutter indentation is less sensitive to confining stresses, with no notable increase of crack number and crack reorientation with increasing confinement. Thus, the CCS disc cutter is more favorable than the V shape one from the perspective of rock fragmentation under confining stresses.
#1Cigdem Keles (VT: Virginia Tech)H-Index: 8
#2Foteini Vasilikou (ARUP Laboratories)H-Index: 1
Last. Michael Karmis (VT: Virginia Tech)H-Index: 6
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Abstract The potential of commercial deployment of CO2 sequestration in unmineable coal seams, as a measure to mitigate the greenhouse gas effect, has been tested through a series of small- to medium-scale CO2 injection projects in the Appalachian Basin, USA. Essential tools for these projects are reservoir simulations in which the involved processes, prior to injection field tests are modeled to enhance understanding and to be used as a decision tool. Due to the large number of modeling input p...
#1Liu Huihui (CUMT: China University of Mining and Technology)H-Index: 4
#2Baiquan Lin (CUMT: China University of Mining and Technology)H-Index: 40
Last. Wei Yang (CUMT: China University of Mining and Technology)H-Index: 21
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#1Tang Bin (Anhui University of Science and Technology)H-Index: 6
#2Hua Cheng (Anhui University of Science and Technology)H-Index: 6
Last. Shiwei Guo (Anhui University of Science and Technology)H-Index: 1
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Abstract TBMs had been introduced to coal mining industries for decades. However, the applications of TBM in coal mines which have vertical shafts as their main accesses were barely reported. This paper presents a case study of TBM tunnelling works in Zhangji coal mine, China. The roadways, having diameter of 4.53 m and average buried depth of 500 m were excavated by a gripper TBM. Before the TBM excavation works, TBM delivering from surface to underground working site through vertical shaft and...
At present, the constant cross section (CCS) disc cutter with flat edge is widely used in TBM tunnelling project. But the problem of serious wear and low rock breaking efficiency appeared when the CCS disc cutter was driven into the high abrasive stratum. The disc cutter with small edge angle is designed in order to enhance the service life of the disc cutter in this paper. The simulation of the two kinds of cutter rings rock breaking were done based on the theoretical analysis used the theoreti...
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 sho...
#1Xing Huang (CAS: Chinese Academy of Sciences)H-Index: 9
#2Quansheng Liu (CAS: Chinese Academy of Sciences)H-Index: 26
Last. Jianping Liu (Sichuan Agricultural University)H-Index: 11
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Abstract With increasing coal mining intensity, the number, length and depth of coal mine roadways is increasing drastically, the traditional drill-&-blast method and comprehensive mechanized driving method, and corresponding support methods are incapable of controlling the surrounding rock stability gradually. Hard rock TBMs (Full-face tunnel boring machine) have significant advantages in terms of fast advance rates, high support capacity, being favorable to environmental protection and low con...
#1Quansheng Liu (CAS: Chinese Academy of Sciences)H-Index: 26
#2Xing Huang (CAS: Chinese Academy of Sciences)H-Index: 9
Last. Jianping Liu (CAS: Chinese Academy of Sciences)H-Index: 11
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Abstract Compared with the drill and blast method, TBM tunnelling has significant advantages with high construction efficiency, low project cost, conducive to environmental protection, favorable stability control of surrounding rock mass, etc. At present in China, it has become the first choice and development trend in the construction of long and deep buried tunnels and over one thousand meters deep coal mine roadways. Recently, the engineering application and fundamental research of TBM tunnel...
#1Liu YanweiH-Index: 4
#2Wang QianH-Index: 1
Last. Hani S. Mitri (McGill University)H-Index: 24
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Gas drainage for the single and low gas permeability coal seam is the key technical problem hampering efficient coal mine gas drainage and without which mining safely cannot be realised in China. To solve this problem, this paper presents an engineering method for enhanced coalbed methane recovery based on high-pressure hydraulic flush from floor tunnels. The first step is to evaluate when the likelihood of coal and gas outburst reaches dangerous levels according to coal seam parameters (includi...
#1Ping Lu (Xi'an University of Science and Technology)H-Index: 1
#2Ping LiH-Index: 1
Last. Tao Yu (Anhui Jianzhu University)H-Index: 1
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The techniques of stress relief mining in low-permeability coal seams and pillarless gob side retained roadway entry using Y-type ventilation and gas drainage systems were developed to control gas outbursts and applied successfully. However, as the mining depth increasing, parts of the gas drainage system are not suitable for mines with high gas emissions. Because larger mining depths cause higher ground stresses, it becomes extremely difficult to maintain long gob side roadways. The greater def...
#1D. Tumac (ITU: Istanbul Technical University)H-Index: 12
#2Cemal Balci (ITU: Istanbul Technical University)H-Index: 14
Abstract A new model is suggested in this study to predict normal and rolling forces acting on CCS type disc cutters by modifying an empirical model developed by Bilgin (1977) for V type disc cutters, which was based on the theoretical model developed by Roxborough and Phillips (1975). The suggested model is based on the fact that V type disc cutters are manufactured with some certain edge radius as a pre-blunting to reduce the premature tool breakages. Giving an edge radius to a sharp V type di...
Cited By1
#1Chuyuan Cao (XTU: Xiangtan University)
#2Kui Zhang (XTU: Xiangtan University)
Cutter performance evaluation is important for shield TBM during the design and refurbishment stage. To face the challenges of choosing the proper cutters for tunneling in complex condition, according to the concept of parameter profile analysis, a systematic evaluation method was proposed. In this novel method, by comparing with their expected best value and the corresponding unacceptable limit, all of the selected performance parameters can be synthesized to assess the proximity of the overall...
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