Abstract
During tunnel blasting excavation in soft rock formations, the dynamic response and time-dependent
behavior of the surrounding rock are critical to construction stability and long-term safety. However, existing research
has insufficiently addressed the damage evolution mechanism of soft rock under the coupled effects of transient
blasting loads and long-term creep. This study, based on a mountain tunnel in Hunan Province, employs a
combination of theoretical analysis, numerical simulation, and parameter inversion to systematically investigate the
dynamic response process of soft rock tunnels under blasting. The main findings are as follows: (1) The established
fractional-order creep-damage constitutive model effectively simulates the dynamic response under blasting, with
numerical results closely matching indoor model tests and deformation prediction errors below 5%; (2) The strain
response of the surrounding rock lags behind the peak blasting stress. Specifically, an instantaneous plastic strain zone
forms in the rock mass closest to the tunnel face under blasting loads. The displacements at the tunnel crown and
invert exhibit a parabolic decline, while the convergence deformations on the left and right sidewalls are
approximately equal. The peak strain in the rock mass occurs after the peak blasting stress. The maximum negative
strain (deformation toward the surrounding rock) near the blasting face appears at 6.3 ms, and the maximum positive
strain occurs at 16 ms; (3) The intelligent parameter inversion method based on the Particle Swarm Optimization
(PSO) algorithm demonstrates high reliability. The optimized values of elastic modulus, Poisson
Key Words
blasting excavation; damage theory; dynamic response; soft rock tunnel
Address
Zhenhua Wang, Lele Lei: 1School of Civil and Architecture Engineering, East China University of Technology, Nanchang 330013, China
Xiqi Liu: Pearl River Water Resources Research Institute, Guangzhou 510611, China
Gang Wang: School of Civil Engineering, Shaoxing University, Shaoxing 312000, China
Dongwei Li: College of Civil Engineering and Architecture, Dalian university, Dalian 116622, China
Abstract
Accurate estimation of the deformation modulus (Erm) is crucial for effective geotechnical modeling for
slope stability analysis. This study introduces an empirical correlation to predict the deformation modulus of a metasedimentary
sandstone outcrop by integrating static and dynamic testing techniques, both in situ and in the laboratory,
where the sandstone exhibits anisotropic characteristics within a meta-sedimentary formation. The prediction
procedure was conducted by first deriving elastic modulus datasets from static and dynamic measurements and
subsequently establishing empirical relationships that linked these parameters to the deformation modulus of the rock
mass. The in-situ static elastic modulus (Ei(stat)) was estimated using Schmidt rebound hammer values, which were
correlated with uniaxial compressive strength (UCS). Meanwhile, the in-situ dynamic elastic modulus (Ei(dyn)) was
determined using the knocking ball test. The laboratory of Ei(stat) and Ei(dyn) were also determined from the laboratory
UCS testing and free-free resonant column (FFRC) testing, respectively. These testing methods were integrated to
create a predictive model for the deformation modulus, following a modified approach by Hoek and Diederichs
(2006). The model demonstrated high prediction accuracy using correlation and error metrics. Integrating static and
dynamic parameters improved reliability, with in-situ modulus (RMSD = 0.75) outperforming lab tests (RMSD =
12.58), emphasizing modulus selection for anisotropic rock slope simulations and reinforcing its suitability for
practical geotechnical design. The findings indicate that the in-situ predictive approach more effectively captures the
structural and anisotropic characteristics of the rock mass, thereby providing a more representative basis for slopescale
deformation analysis.
Address
Mohd Mustaqim Mohd-Nordin: School of Civil Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang, Malaysia;
Faculty of Civil Engineering, Universiti Teknologi MARA (Pahang), 26400 Bandar Tun Abdul Razak,
Jengka, Pahang, Malaysia
Mohd Ashraf Mohamad Ismail: School of Civil Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang, Malaysia
Mazlina Razali: Faculty of Civil Engineering, Universiti Teknologi MARA (Penang), 14400 Permatang Pauh,
Penang, Malaysia
Abstract
The high compressibility and low bearing capacity of soft clay pose serious challenges to foundation and
earth structure engineering. To address these issues, this study investigates the one-dimensional compression
behavior of soft clay stabilized with a lime-fly ash composite, with particular emphasis on the effects of fly ash
content and curing time. Oedometer tests were conducted on specimens treated with 5% lime and varying fly ash
contents (0-25%) after curing periods of 3 h, 7 d, and 28 d. The compression response was evaluated using e–p and elogp
relationships, while microstructural evolution was examined through scanning electron microscopy (SEM). The
results show that lime-fly ash stabilization significantly reduces soil compressibility and flattens the e–p curves
compared with untreated soft clay. The stabilized specimens exhibit a distinct bilinear e-logp response with a clear
compression yield stress, indicating a transition from a low-compressibility pre-yield stage to a highercompressibility
post-yield stage. Increasing fly ash content effectively decreases the compression index and enhances
yield stress, with an optimal fly ash dosage of approximately 20% under the curing time of 28d at which the postyield
compression index is reduced by up to 50.4% and the yield stress is increased by more than 80.3%. Prolonged
curing further improves compression resistance by promoting pozzolanic reactions and the formation of cementitious
products such as calcium silicate hydrate and calcium aluminate hydrate, leading to a denser and more stable soil
structure. Microstructural observations confirm that the macroscopic compression behavior is closely associated with
particle flocculation, pore filling, and cementation effects. These findings provide a mechanistic understanding of
compression yield behavior in lime-fly ash stabilized soft clay and offer practical guidance for the sustainable
improvement of soft ground in foundation and earth structure applications.
Key Words
compressibility; curing time; fly ash; lime; soft clay
Address
Taoyuan Dong, Patrick Banda, Shuai Yang,
Zhehao Qiu, Jianhua Wang, Jie Yin: Department of Civil Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China
Abstract
The formation adaptability of Tunnel Boring Machines (TBM) is a critical determinant of success in
deep-buried long tunnels facing complex geological conditions. However, traditional adaptability evaluations often
struggle to process heterogeneous data and are prone to unjustified parameter coupling. To address these challenges,
this paper proposes an Intelligent Evaluation Decision Support System for TBM Tunneling (IEDSS-TBMT) based
on fuzzy mathematics and rule reasoning. First, a comprehensive evaluation index system comprising 24
independent indicators is established using a modified Delphi method and the Analytic Hierarchy Process (AHP).
Second, an Object-oriented Knowledge Processing System (OKPS) is developed to encapsulate fuzzy IF-THEN
rules. This architecture features a unique multi-level decoupling mechanism that effectively prevents the theoretical "compensation effect" among unrelated evaluation parameters. Finally, the proposed system is applied to the
Gaoligongshan high-speed railway tunnel project. The calculated comprehensive fitness score of 0.8313 (Grade IIa)
demonstrated a high matching degree with actual field conditions. Further quantitative verifications using
macroscopic downtime metrics and Case-Based Reasoning (CBR) confirmed the framework's high stability and low
sensitivity to geological uncertainties. The results indicate that IEDSS-TBMT provides a highly reliable, data-driven
decision-making tool for TBM selection and pre-construction macro-evaluation.
Key Words
adaptability evaluation; artificial intelligence; deep tunnel; fuzzy mathematics; system
development; TBM
Address
Jinwu Zhan, Yijie Chen, Chiyu Yang: 1School of Civil Engineering, Fujian University of Technology, No. 69, Xuefu South Road, Shangjie Town,
Minhou County, Fuzhou City, Fujian Province, China
Guangzhao Du: Department of civil engineering, China Railway No.11 Engineering Group Co., Ltd., No. 277,
Zhongshan Road, Wuchang District, Wuhan City, Hubei Province, China
Zhenxing Zou: Fujian Polytechnic of Water Conservancy and Electric Power, Sanming 366000 Fujian, China
Abstract
The particle gradation of Yellow River silt varies in different basins of the Yellow River. Additionally, the
silt exhibits regional differences in mechanical properties. A series of consolidated drained triaxial shear tests was
carried out to study the effect of particle gradation on the shear behavior of Yellow River silt. This study
systematically investigated the effects of the coefficient of uniformity Cu and coefficient of curvature Cc on the stress–
strain relationship, development law of volumetric strain, and shear strength parameters of Yellow River silt. Based
on scanning electron microscopy (SEM) images of the Yellow River silt obtained following staining treatment, the
shear response mechanisms of the silt with different gradations were analyzed at the microscopic scale, with results
observed as follows. Firstly, the peak deviator stress of the silt was observed to decrease with increasing Cu but
increase with increasing Cc. The optimum gradation of Yellow River silt was experimentally demonstrated to exist.
Secondly, the cohesion c of the silt increased with increasing Cu and Cc. The internal friction angle o of the samples
decreased with increasing Cu and increased with increasing Cc. Finally, the dilation of the Yellow River silt was
influenced by particle gradation. Based on these findings, a formula combining Cu, Cc and shear strength was
developed. SEM images can be used to provide new insights into the mechanical properties of Yellow River silt with
different gradations.
Key Words
particle gradation; shear strength parameters; triaxial test; Yellow River silt
Address
Hao Chen: Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China
Yang Li, Yuke Wang: School of Water Conservancy and Transportation, Zhengzhou University, Zhengzhou 450001, Henan, China;
Provincial and Ministerial Collaborative Innovation Center for Underground Engineering Disaster Prevention
and Control, Zhengzhou 450001, Henan, China
Abstract
This study evaluates the scour depth around underwater perforated structures, such as artificial reefs,
using an integrated approach of analytical, numerical, and field monitoring methods. Perforated structures exhibit
unique hydrodynamic behaviors, including internal flow penetration, pressure fluctuations, and turbulence
generation. In this research, Sumer's empirical formula and the FLOW-3D numerical model were employed to
predict scour depth around these structures under steady current conditions. A comparison of the analytical and
numerical approaches showed high agreement. Based on this result, a modified empirical equation for perforated
structures was proposed. The proposed equation demonstrated high predictive accuracy with a coefficient of
determination (Ro2) of 0.92. Furthermore, the group effect of structures was assessed through numerical simulations
and field monitoring of artificial reef colonies installed in the sea area around Geomun island, South Korea. The
results revealed that scour depth is influenced not only by the structure's geometry and flow velocity but also by the
colony size, with smaller reef clusters experiencing deeper scour under moderate velocity conditions. This study
provides a reliable predictive equation for scour depth around perforated structures and elucidates the interaction
effects of colony size for ensuring long-term stability.
Key Words
artificial reef; field monitoring; numerical analysis; perforated structure; scour depth; sumer's
empirical formula
Address
Young-sang Kim: Department of Civil Engineering, Chonnam National University, 77 Yongbong-ro, Buk-gu,
Gwangju 61186, Republic of Korea
Jung-goo Kang, Gyeongo Kang: Department of Civil Engineering, Gwangju University, 277 Hyodeck-ro, Nam-gu,
Gwangju, 61743, Republic of Korea
Jong-kyu Kim: Department of Nabal Architecture and Ocean Engineering, Chonnam National University, 50,
Daehak-ro, Yeosu-si, Jeollanam-do, 59626, Republic of Korea
open access