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| CONTENTS | |
| Volume 45, Number 1, April10 2026 |
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Abstract
This study conducted a series of rock linear cutting tests on Finike limestone using a conical pick,
followed by sieving tests on the resulting rock fragments, to investigate the effect of cutting speed on cuttability and
product characteristics. As the cutting speed increased, both tool forces and specific energy (SE) increased. However,
as the cutting depth increased, the effect of cutting speed on cuttability lessened. For tool forces, the cutting force
(FC) increased more significantly than the normal force (FN), and the mean tool force increased more than the peak
tool force. The increase in SE was attributed to the additional work (W) required during the rock cutting process, as
cutting volume is not affected by cutting speed. The increase in cutting speed resulted in the product becoming
smaller and finer. Specifically, the size of the rock chips decreased as the cutting speed increased, which was
consistent with predictions based on the changes in the peak-to-mean tool force ratio and the optimal ratio of line
spacing to cutting depth (s/p) as the cutting speed increased. Furthermore, as the cutting speed increased, the
proportion of powder in the product increased, while the proportion of rock chips decreased. The findings of this
study provide a better understanding of the effect of cutting speed on the performance of mechanical excavators.
Key Words
conical pick; cutting speed; rock chips; rock cutting; specific energy; tool forces
Address
Ji-seok Yun: Department of Geotechnical Engineering Research, Korea Institute of Civil Engineering and Building
Technology, 283 Goyangdae-ro, Ilsanseo-gu, Goyang-si, 10223, South Korea
Han-eol Kim:Department of Geotechnical Engineering Research, Korea Institute of Civil Engineering and Building
Technology, 283 Goyangdae-ro, Ilsanseo-gu, Goyang-si, 10223, South Korea;
Underground Safety Evaluation Center, Korea Expressway Corporation Research Institute,
24, Dongtansunhwan-daero 17-gil, Hwaseong-si, 18489, South Korea
Abstract
In this study, effect of a tunnel as an underground irregularity on the dynamic response of the surface is
investigated. To attain this goal, the variation of the frequency content and amplification behavior of the surface
because of the presence of the tunnel is estimated by a time domain fully nonlinear analysis method. To make the
results useful in practice, the variation of the maximum spectral amplification factor (MSAF) as the average of the
site response to twenty-four real earthquakes scaled to a target spectrum are estimated for two soft and stiff clayey
sites with tunnels at two different depths. The results showed that while the maximum response spectrum of the
surface points close to the tunnel axis happens in lower period, it moves to the higher period by the increase distance
from the tunnel axis. It was seen that the main reason of the seen amplifications is the change in the frequency content
of the surface points. Also, the affected surface distance from the tunnel axis is greater for the soft clayey site case. By
the increase in the tunnel depth, the location of the MSAF peak point moves farther from tunnel axis. Also, the
increase in the tunnel depth decreases the MSAF. Considering the dimension and geometry of the cases studied in
this study, no sign of the surface wave generation due to the presence of the tunnel was encountered.
Key Words
clayey site; dynamic response; fully nonlinear analysis; lined tunnel; numerical modeling; site
effect; spectral amplification
Address
Hadi Khanbabazadeh: Department of Istanbul Technical University, 34469 Maslak Campus, Istanbul, Turkey
- Evaluation of seismic active earth pressure using the concept of soil arching G. Santhoshkumar, Soumisree Chowdhury
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| Abstract; Full Text (1395K) . | pages 45-59. | DOI: 10.12989/gae.2026.45.1.045 |
Abstract
The evaluation of seismic active earth pressure is a classical problem in geotechnical earthquake
engineering. The earth pressure distribution is idealized as linear in conventional theories, but this is not valid in
reality. Utilizing the concept of soil arching, the present study attempts to evaluate the seismic active earth pressure on
an inclined rigid retaining wall that supports a horizontal cohesionless backfill. By considering the planar failure
surface and pseudo-static seismic forces within the failure domain, an analytical formulation is proposed to determine
the optimum rupture surface and maximum seismic active earth pressure. It is observed that the soil arching effect
influences the stress distribution behind the wall due to the presence of wall roughness. The normalized stress
distribution throughout the depth of the backfill is found to be curvilinear, contrary to the conventional theories. It is
primarily influenced by soil-wall interface properties, wall geometry and seismic inertial forces. Further, the point of
application of seismic active thrust depends on various input parameters and tends to ascend towards the ground
surface as seismicity and wall roughness increase.
Key Words
active earth pressure; earthquake; pseudo-static analysis; retaining wall; soil arching
Address
G. Santhoshkumar, Soumisree Chowdhury: School of Infrastructure, Indian Institute of Technology Bhubaneswar, Odisha, PIN-752050, India
- Partitioned fracture law and prediction method of near-field roof in shallow-buried thin bedrock super-long working faces: a case study Guohao Meng, Dawei Yin, Liqiang Chen
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| Abstract; Full Text (2143K) . | pages 61-77. | DOI: 10.12989/gae.2026.45.1.061 |
Abstract
To explore the partitioned fracture law of a near-field roof in shallow-buried, thin-bedrock, super-long
working faces, an equivalent stiffness foundation beam mechanical model of super-long working faces was
established. The effects of face length l, coal seam mining height mc, main roof elastic modulus E, main roof
thickness h, support stiffness k2, and roadway sidewall stiffness K on the bending moment distribution of the main
roof were investigated. Results show that the bending moment distribution curve of the main roof occurs in two
patterns: single-peak and M-shaped double-peak forms. The main roof exhibits four fracture modes: central bending
subsidence, central point fracture, central regional fracture, and bilateral partitioned fracture. The influence patterns of
various factors on roof fracture modes were elucidated. The kEIl effect influencing main roof fracture along the
working face dip was analyzed, and a composite parameter criterion for main roof fracture along the working face
dip was proposed: when [(k/EI)1/4l] [6.7, 7], the roof exhibits central regional fracture, when [(k/EI)1/4l] > 7, the roof
shows bilateral partitioned fracture, when [(k/EI)1/4l] < 6.7, the roof shows central point fracture. A prediction method
for main roof fracture patterns along the working face dip was established. Through comparative analysis of field
measurements and theoretical calculations, the roof fracture characteristics were verified, and the time–space
correlation between roof partitioned fracture and support resistance distribution was revealed. The results provide a
theoretical basis for disaster prevention in shallow, ultra long working faces with thin bedrock.
Key Words
composite parameter criterion; disaster prevention; partitioned fracture; shallow-buried thin
bedrock; super-long working faces
Address
Guohao Meng, Dawei Yin: College of Energy and Mining Engineering, Shandong University of Science and Technology,
Qingdao, 266590, China;
Shandong Key Laboratory of Intelligent Prevention and Control of Dynamic Disaster in Deep Mines,
Shandong University of Science and Technology, Qingdao 266590, China
Liqiang Chen: Shandong Key Laboratory of Intelligent Prevention and Control of Dynamic Disaster in Deep Mines,
Shandong University of Science and Technology, Qingdao 266590, China
- Analytical modeling and field verification of roof failure mechanisms in steep extra-thick coal seams under permafrost conditions Yaning Zhang, Zhanbo Cheng, Xiaoyan Liu, Lulu Liu
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| Abstract; Full Text (3183K) . | pages 079-93. | DOI: 10.12989/gae.2026.45.1.079 |
Abstract
The redistribution of in-situ stress within the coal and surrounding rock mass leads to progressive
deformation and eventual structural failure during mining process. Understanding the failure mechanisms of
overlying strata in steeply inclined extra-thick coal seams is critical for improving safety and optimizing mining
strategies under complex geological conditions. In this study, taking 20# steep extra-thick coal seam in Jiangcang No.
1 coal seam located in Qinghai Province, China, as an engineering background, each mining level is subdivided into
three segments, and a mechanical model based on elastic thin plate theory is developed to derive the expressions for
both initial and periodic weighting step distances of the overlying strata. The results indicate that the immediate roof
experiences its first failure during the second segment of the first mining level, characterized by a vertical O-X
fracture pattern when the working face advances to 38 m. The corresponding periodic weighting step distance is
calculated to be 23.48 m. Following the collapse of the immediate roof, the accumulated caved materials fill the voids
above the coal seam, effectively reducing the suspension span of the main roof. As a result, the main roof remains
intact after the completion of the first mining level. In the second mining level, the main roof undergoes its initial
failure in the second segment at an advance distance of 97 m, exhibiting a horizontal O-X failure mode along the
strike direction. The periodic weighting step distance for the main roof is subsequently determined to be 59.96 m.
These findings clarify the distinct failure modes and weighting characteristics of steep extra-thick seams, providing a
theoretical basis for safer coal recovery and for protecting the integrity of overlying frozen soil layers in cold regions.
Key Words
failure type; mechanical model; overlying strata movement; steep extra-thick coal seam;
sublevel caving mining
Address
Yaning Zhang: Chinese Institute of Coal Science, Beijing 100013, China
Zhanbo Cheng: School of Earth Sciences and Engineering, Nanjing University, Nanjing, 210023, China;
School of Civil and Environmental Engineering, Nanyang Technological University,
Nanyang 639798, Singapore
Xiaoyan Liu, Lulu Liu: School of Mechanics and Civil Engineering, China University of Mining and Technology,
Xuzhou 221116, China
- Study on damage evolution characteristics of sandstone under cyclic loading with acid-base dry-wet coupling effect Weijing Yao, Shaoge Rui, Yongjiang Luo, Hanbing Xu, Jianyong Pang
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| Abstract; Full Text (8053K) . | pages 95-123. | DOI: 10.12989/gae.2026.45.1.095 |
Abstract
To investigate the influence mechanism of groundwater erosion on disturbed rocks during the excavation
of coal mine roadways, multi-stage cyclic loading and unloading tests were conducted on sandstone samples treated
under different acid-base dry-wet cycling conditions. Combined with Digital Image Correlation (DIC), Scanning
Electron Microscopy (SEM), X-ray Diffraction (XRD), and Energy Dispersive Spectroscopy (EDS), this study
systematically analyzed the energy evolution, mechanical properties, damage variables, and strain field evolution of
deteriorated sandstone, as well as the characteristics of its micro-morphology, phase composition, and element
changes, thereby revealing the internal damage mechanism of sandstone. The results show that with the increase of
cyclic grade, the deformation modulus of sandstone first increases sharply and then decreases slowly, while the
cumulative residual strain and damage variables increase continuously, and acid-base erosion further amplifies the
differences in the above mechanical parameters. The input energy, elastic energy, and dissipation energy of sandstone
all increase with the rise of stress grade, and elastic energy always dominates the energy composition. The increase in
the number of acid-base dry-wet cycles leads to a gradual separation of the growth curves of input energy and elastic
energy, and the energy dissipation ratio shows a trend of first decreasing and then increasing. Strain field observations
based on DIC technology indicate that sandstone fracture initiates from local strain concentration areas, followed by
gradual propagation and coalescence of cracks, ultimately resulting in overall failure of the specimens. Microscopic
tests demonstrate that acid-base solutions corrode sandstone samples and react chemically with the main components
of sandstone, leading to an increase in the number of surface pores and cracks, while dry-wet cycles cause continuous
shedding of rock particles. The coupling effect of chemical erosion and physical action leads to the continuous
accumulation of internal damage in sandstone and the gradual aggravation of its deterioration. The findings of this
research can serve as a theoretical foundation for evaluating the stability and designing support systems for
underground structures affected by groundwater erosion, providing guidance for roadway support design and longterm
stability assessment in water-eroded underground rock engineering.
Key Words
acid-base dry-wet cycles; cyclic loading and unloading; energy evolution; damage mechanism;
sandstone
Address
Weijing Yao: State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University,
Chongqing 400044, China;
School of Civil Engineering and Architecture, Anhui University of Science and Technology,
Huainan 232001, China;
Engineering Research Center of Underground Mine Construction, Ministry of Education,
Anhui University of Science and Technology, Huainan 232001, China;
Zhejiang Key Laboratory of Rock Mechanics and Geohazards, Shaoxing University,
Shaoxing 312000, China
Shaoge Rui, Hanbing Xu: School of Civil Engineering and Architecture, Anhui University of Science and Technology,
Huainan 232001, China
Yongjiang Luo: State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University,
Chongqing 400044, China
Jianyong Pang: School of Civil Engineering and Architecture, Anhui University of Science and Technology,
Huainan 232001, China;
Engineering Research Center of Underground Mine Construction, Ministry of Education,
Anhui University of Science and Technology, Huainan 232001, China
