Joints and confining stress influencing on rock fragmentation with double disc cutters in the mixed ground

2019 ◽  
Vol 83 ◽  
pp. 461-474 ◽  
Author(s):  
Xianshan Liu ◽  
Ming Xu ◽  
Pengwei Qin
Keyword(s):  
Rock Fragmentation ◽  
Confining Stress ◽  
Disc Cutters ◽  
Mixed Ground

scholarly journals The Effects of Confining Stress on Rock Fragmentation by TBM Disc Cutters

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
S. F. Zhai ◽  
S. H. Cao ◽  
M. Gao ◽  
Y. Feng
Keyword(s):  
Confining Pressure ◽  
Numerical Results ◽  
Rock Fragmentation ◽  
Disc Cutter ◽  
Confining Stress ◽  
Disc Cutters ◽  
Initiation And Propagation ◽  
Maximum Angle ◽  
Indentation Tests ◽  
Crushed Zone

In this paper, General Particle Dynamics (GPD3D) is developed to simulate rock fragmentation by TBM disc cutters under different confining stress. The processes of rock fragmentation without confining pressure by one disc cutter and two disc cutters are investigated using GPD3D. The crushed zone, initiation and propagation of cracks, and the chipping of rocks obtained from the proposed method are in good agreement with those obtained from the previous experimental and numerical results. The effects of different confining pressure on rock fragmentation are investigated using GPD3D. It is found that the crack initiation forces significantly increase as the confining stress increases, while the maximum angle of cracks decreases as the confining stress increases. The numerical results obtained from the proposed method agree well with those in previous indentation tests. Moreover, the effects of equivalent confining stress on rock fragmentation are studied using GPD3D, and it is found that rock fragmentation becomes easier when the equivalent confining stress is equal to 15MPa.

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

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Gaofeng Wang ◽  
Ting Ren ◽  
Gaolei Zhu
Keyword(s):  
Thrust Force ◽  
Coal Mines ◽  
Rock Fragmentation ◽  
Disc Cutter ◽  
Confining Stress ◽  
Disc Cutters ◽  
Underground Coal Mines ◽  
Indentation Tests ◽  
Boring Machines ◽  
Maximum Thrust

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.

The Crushing Mode and the Optimal Penetration of Two Disc Cutters Cutting Marble under Different Confining Stress

2013 ◽  
Vol 353-356 ◽  
pp. 1417-1421 ◽  
Author(s):  
Bin Shen ◽  
Yi Min Xia ◽  
Jian Jian Gu ◽  
Yan Chao Tian
Keyword(s):  
Energy Consumption ◽  
Specific Energy ◽  
Specific Energy Consumption ◽  
Tunnel Boring Machine ◽  
Element Model ◽  
Confining Stress ◽  
Tunnel Boring ◽  
Disc Cutters ◽  
Full Face ◽  
Rock Tunnel

According to the actual working condition of the full face hard rock tunnel boring machine (TBM), a 2-D discrete element model for breaking marble by two TBM disc cutters is established, it simulates the whole progress of cracks production and propagation under different confining stress and penetration; based on CSM prediction model, forces of two cutters and specific energy consumptions are calculated to determine the best penetration. The simulating result shows that there are three kinds of breaking modes of marble under different confining stress and penetration; As well as the trend that specific energy consumption decrease first and then increase with the penetration increases, and there is optimal penetration to make specific energy consumption the lowest each confining stress. The optimal penetration and the lowest specific energy consumption are determined when confining stress range from 0 to 40MPa according to the simulation results.

Numerical Simulation of Rock Fragmentation Process Induced by Two Disc Cutters

2011 ◽  
Vol 366 ◽  
pp. 224-228 ◽  
Author(s):  
Lin Tao Man ◽  
Shou Ju Li
Keyword(s):  
Rock Breaking ◽  
Rock Fragmentation ◽  
Fragmentation Process ◽  
The Finite Element Method ◽  
Penetration Process ◽  
Disc Cutters ◽  
Adjacent Disc ◽  
Realistic Description ◽  
Cutter Spacing ◽  
Fragmentation Processes

Rock fragmentation processes induced by two cutters were simulated by ABAQUS software with different cutter spacing. A series of numerical experiments reproduce the progressive process of rock fragmentation in indentation. The influence of different cutter spacing on the penetration process can also be clearly researched. Rock fragmentation process induced by two TBM disc cutters was performed using the finite element method. The simulation not only provided a realistic description of the rock fragmentation mechanism, but also supported the sufficient proof for the cutter spacing optimization between adjacent disc cutters for a given penetration depth. When the penetration is 6 mm, the cutter spacing optimization is 48 mm. The result shows that the numerical simulations will contribute to an improved knowledge of rock fragmentation in indentation and will be useful for performance assessment of TBM, which will enhance the efficiency of rock breaking.

Rock fragmentation under different installation polar angles of TBM disc cutters

2017 ◽  
Vol 24 (10) ◽  
pp. 2306-2313 ◽  
Author(s):  
Yong-liang Cheng ◽  
Jue Zhong ◽  
Yong-bing Mei ◽  
Yi-min Xia
Keyword(s):  
Rock Fragmentation ◽  
Disc Cutters

Physical and numerical studies of rock fragmentation subject to wedge cutter indentation in the mixed ground

2018 ◽  
Vol 71 ◽  
pp. 354-365 ◽  
Author(s):  
Xiao-Ping Zhang ◽  
Pei-Qi Ji ◽  
Quan-sheng Liu ◽  
Qi Liu ◽  
Qi Zhang ◽  
...  
Keyword(s):  
Rock Fragmentation ◽  
Numerical Studies ◽  
Mixed Ground

Numerical Study of the Rock Fragmentation by Three TBM Cutters

2012 ◽  
Vol 594-597 ◽  
pp. 3-7
Author(s):  
Yan Wang ◽  
Zheng Zhao Liang
Keyword(s):  
Numerical Study ◽  
Rock Breaking ◽  
Rock Fragmentation ◽  
Numerical Code ◽  
Time Interval ◽  
The Finite Element Method ◽  
Whole Process ◽  
Disc Cutters ◽  
Initiation And Propagation ◽  
Damage Theory

Based on the mesoscopic damage theory and the finite element method, a numerical code RFPA was applied to investigate the rock fragmentation by three TBM cutters loaded one after another in different time interval. The whole process of crack initiation and propagation was successfully simulated by the cutters loaded with different step intervals. The time interval of the disc cutters has significant influence on the fracture patterns and the rock breaking efficiency. The simulated results show that there are three types of breakage mode of the rock subjected to compression by the cutters.

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