Abstract
This study investigates the degradation mechanism of shear strength in overlying loess within the sliding
zones of loess–red bed landslides governed by base–cover interfaces in the plateau regions of Northwest China. The
Chigou, Luoyugou, and Shuiyanzhai landslides in Gansu Province were selected as representative cases. A series of
seepage–corrosion tests, direct shear tests, X-ray diffraction (XRD) analysis, ion chromatography (IC), and scanning
electron microscopy (SEM) were conducted to examine the evolution of mineral composition, chemical
composition, and microstructure during seepage-induced strength deterioration. The main findings are as follows: (1)
Both the internal friction angle and cohesion decrease progressively during seepage, with cohesion exhibiting a more
pronounced reduction. (2) Intense chemical reactions—primarily hydrolysis, acid–base exchange, and ion
exchange—occur during the water–loess interaction, particularly in the early seepage stages, fundamentally altering
the material composition and weakening the soil structure. (3) These reactions result in significant microstructural
changes, including increases in pore number, porosity, and pore area, which correspond to macroscopic strength
deterioration.
Address
Xiaomou Ma, Guoxiang Tu, Bo Luo, Cheng Tan, Zhanjie Dong,
Xiaoye Deng, Anrun Li: State Key Laboratory of Geohazard Prevention and Geo-environment Protection,
Chengdu University of Technology, 610059, Chengdu, China
Abstract
The permeability and compressibility of a saturated tailing materials are important parameters in the field
of mining safety and geotechnical engineering. The geometric characteristics of a porous medium are key factors in
the prediction of its permeability and compressibility. In this paper, the compression and hydraulic characterizes of
different gradation tailings through high-stress permeability compression tests were herein investigated. Then, the
relationship between the geometric parameters and the high-stress permeability and compressibility of tailings is
established. Based on PFC numerical simulation, the non-spherical cluster particles with different fractal dimension
and other geometric parameters were constructed, and the compression simulations considering particle breakage
were carried out. Using tests and simulations analysis, the influence degree on the compressibility of tailings is as
follows: Ultrafine content (Fc) > Roundness (Rc) > Sphericity (Sk) > Fractal dimension (Fd). Numerical simulation
proves that particle breakage and water film are closely related to particle shape, and the prediction formula proposed
has a wider scope of application on high-stress permeability and compressibility of saturated tailings materials.
Key Words
geometrical parameter; high stress; numerical simulation; permeability and compression;
saturated tailings material
Address
Changkun Ma and Chao Zhang: State Key Laboratory of Geomechanics and Geotechnical Engineering Safety,
Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, Hubei 430071, China;
Key Laboratory of slope safety risk warning and disaster prevention and mitigation,
Ministry of Emergency management, Wuhan, Hubei 430071, China
Ruixin Li: State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University,
Wuhan, Hubei 430071, China
Qinglin Chen: School of Resources and Environmental Engineering, Jiangxi University of Science and Technology,
Ganzhou, Jiangxi 341000, China
Abstract
To improve the efficiency and safety of shield machines when cutting pile foundation rebars, abrasive
waterjet (AWJ) assisted cutting technology has been identified as a feasible solution. However, the cutting
performance of AWJ is highly influenced by abrasive concentration. This paper presents a systematic theoretical and
experimental study to quantify the effect of abrasive concentration on the cutting performance of rebars and to
determine the optimal concentration range. Using an established effective kinetic energy model of abrasive particles,
and supported by experimental results, it was found that abrasive concentration significantly influences the cutting
depth of rebars. As the concentration increases, the cutting performance of AWJ initially rises rapidly and then
gradually declines, with optimal performance occurring at concentrations between 8%-10%. The effect on cutting
width is relatively minor, remaining stable in the range of 2.5-3 mm. Furthermore, abrasive particle size plays a
critical role: smaller particles (80 mesh) produce deeper grooves, whereas larger particles (24 mesh) lead to a 67%-
69% reduction in groove depth. These research findings offer valuable insights and guidance for the design and
construction of AWJ assisted shield machines in combined cutting of pile foundation rebars.
Address
Bin Xu: The State Key Laboratory for Tunnel Engineering, Shandong University, Jinan 250061,
Shandong, People's Republic of China;
Institute of Geotechnical and Underground Engineering, Shandong University, Jinan 250061,
Shandong, People's Republic of China;
School of Qilu Transportation, Shandong University, Jinan 250061, Shandong, People's Republic of China
Jian Qiu: Jinan Heavy Industries Group Co., Ltd, Jinan, Shandong, China
Xinjie Huang:1The State Key Laboratory for Tunnel Engineering, Shandong University, Jinan 250061,
Shandong, People's Republic of China;
Institute of Geotechnical and Underground Engineering, Shandong University, Jinan 250061,
Shandong, People's Republic of China
School of Civil Engineering, Shandong University, Jinan 250061, Shandong, People's Republic of China
Bo Zhang: School of Civil Engineering, Shandong University, Jinan 250061, Shandong, People's Republic of China
Biao Li:1The State Key Laboratory for Tunnel Engineering, Shandong University, Jinan 250061,
Shandong, People's Republic of China
2Institute of Geotechnical and Underground Engineering, Shandong University, Jinan 250061,
Shandong, People's Republic of China;
School of Civil Engineering, Shandong University, Jinan 250061, Shandong, People's Republic of China
Abstract
Soft rock tunnels under high in-situ stress and complex hydrogeological conditions are highly susceptible
to large deformations, posing serious risks to construction safety and efficiency. This study provides a systematic
review of current research and development trends in soft rock large deformation, using bibliometric and
visualization analysis. The review focuses on deformation mechanisms and corresponding control strategies. Studies
show that large deformations are driven by stress redistribution, structural degradation, and environmental influences.
These deformations typically evolve in a nonlinear, irreversible, and staged manner. Mechanistic investigations have
advanced in key areas such as nonlinear deformation paths, fracture propagation, time-dependent behavior, multifield
coupling, and rock-support interaction. In terms of control, yielding supports, energy-absorbing components,
high prestress anchors, and intelligent monitoring systems have shown significant effectiveness. Machine learningbased
prediction models have also demonstrated potential for deformation identification and early risk warning.
Nevertheless, significant limitations remain. Mechanistic analyses are largely macroscopic and phenomenological,
and dynamic multi-physical coupling is insufficient. Control strategies lack standardization and long-term validation,
while predictive models are constrained by data quality and interpretability. Future work should develop multi-scale
models, establish open case repositories, and implement intelligent closed-loop control to enable accurate prediction
and active management, enhancing tunnel resilience and sustainability.
Key Words
bibliometric analysis; failure mechanism; large deformation; soft rock tunnel; support
measures; VOSviewer
Address
Baomin Zhang, Qingfei Luo, Zhengzheng Wang: School of Civil Engineering, Dalian University of Technology, Dalian, Liaoning 116024, China
Song Yuan: Sichuan Communication Survey and Design Institute Co., Ltd., Chengdu, Sichuan 610017, China
Bin Li, Yijie Zhang: Sichuan Beixin Tianzhao Investment Development Co., Ltd., Guangyuan, Sichuan 628005, China
Abstract
This study employed distributed fiber-optic sensors (DFOSs) to examine twin-tunnelling-induced pile
bending responses and to identify the primary influencing factors across different tunnelling stages. The high spatial
resolution of DFOS measurements enabled detailed analysis of the bending strain energy (U) along the pile.
Throughout each tunnel advancement, both U and negative peak bending moment (NPBM) underwent one loading
and one unloading process, exhibiting a consistent positive correlation. This investigation introduced two crucial
parameters: the negative peak energy density (Un), derived from NPBM, and the mean strain energy density (Um),
derived from U. The long-term measurements revealed that the Um/Un ratio remained within a narrow interval (width
< 0.10) throughout most Lpt intervals, allowing a zero-intercept linear function to serve as the development line for
normal strain energy concentration. The level of strain energy concentration, which is correlated with risk, are
quantifiable via the deviation value of Un from the development line. In particular, positive and negative deviation
values of Un occurred at the peak and steady states, respectively, corresponding to high and low strain energy
concentrations. Additionally, the development of pile-soil interface contact stress was investigated using threedimensional
numerical modelling, providing deeper insight into the loading and unloading mechanisms.
Key Words
distributed fiber-optic sensors; loading and unloading processes; pile bending responses; strain
energy concentration; twin tunnels
Address
Liangyi Cai, Tingjin Liu, Huashan Zhong, Junxian Xiao, Zhijie Peng, Zhan Liang: School of Civil Engineering and Transportation, South China University of Technology,
Guangzhou 510640, Guangdong, China
Zhixiong Li: Guangzhou Metro Construction Management Co., Ltd, Guangzhou 510220, Guangdong, China
Wufeng Mao: Guangzhou Metro Design and Research Institute Co., Ltd., Guangzhou 510010, Guangdong, China
Abstract
Slope stability analysis, traditionally formulated in two-dimensional (2D) under plane strain conditions,
requires three-dimensional (3D) analysis where plain strain condition is violated such as in case of corner failures or
variations in the longitudinal direction. This study presents 3D slope stability analysis using a Finite Element Method
(FEM) program based on the Strength Reduction Technique (SRT). Stress redistribution is achieved through a viscoplastic
algorithm, and the Mohr-Coulomb strength criterion is applied to predict stress states. Slope failure is
simulated when iterative calculations show non-convergence, indicating that the equilibrium of the forces could no
longer be achieved. The program has been validated by analysing problems, including slopes subjected to earthquake
forces and water loading, and the obtained result is compared with the results of existing literature. For ponding
water, equivalent nodal loads are derived for slopes discretized using 20-noded brick elements. A novel extrapolation
method calculates nodal stresses from sampling points, minimizing fitting errors while preserving the trends. Results,
such as deformed meshes, contour plots of visco-plastic strain, yield function, and pore-water pressure, illustrate
failure states. Comparison with other studies demonstrates strong agreement, confirming the program's accuracy and
robustness in capturing complex slope failure mechanisms.
Key Words
3D slope stability analysis; finite element modelling; mohr-Coulomb criteria; strength
reduction technique; visco-plasticity
Address
Prakriti, A. Burman, S.S. Choudhary, Guru Das: Department of Civil Engg., National Institute of Technology Patna, India
