Abstract
The construction of structures near slopes has nowadays become inevitable. and several theoretical models have
been proposed to estimate the ultimate bearing capacity of foundations located on slops. However, slopes with inclined layered
soils have so far remained insufficiently explored. This study examines the influence of slope angle and strip foundation location
on the ultimate bearing capacity of such slopes through experimental and numerical analyses. The results indicate that a decrease
in slope angle and an increase in setback distance (i.e., the horizontal distance from the foundation edge to the slope crest)
enhance the ultimate bearing capacity. Additionally, compared to homogeneous slopes with similar dimensions and setback
distances, slopes with a weak offset layer (a weak layer in the foreground) and those with a weak interlayer exhibit a reduction in
ultimate bearing capacity. Specifically, for slopes with angles of 30, 45, and 60, reductions of approximately 8%, 20%, and
31% were observed for weak offset layers, while reductions of 10%, 19%, and 28% were noted for weak interlayers. However,
as the setback distance increases, these differences diminish following a quadratic function. At a distance of approximately four
to six times the foundation width, the ultimate bearing capacity becomes comparable to that of a strip foundation situated on
level ground.
Address
Kourosh Pourmohammadi and Ahad Bagherzadeh Khalkhali: Department of Civil Engineering, SR.C., Islamic Azad University, Tehran, Iran
Rouzbeh Dabiri: Department of Civil Engineering, Ta.C., Islamic Azad University, Tabriz, Iran
Mehdi Mahdavi Adeli: Department of Civil Engineering, WT.C., Islamic Azad University, Tehran, Iran
Abstract
In the e-(p'/pa) plane, the critical state line (CSL) under different gradations exhibits translation and rotation, which
increases the uncertainty of the state parameter. The constitutive model based on the state parameter faces challenges in
predicting whether coarse-grained soil will exhibit dilatancy or contraction. The selection of the void ratio index is one of the
important factors. This study conducts large-scale triaxial compression tests under different gradations, introduces the concept of
skeleton void ratio, and compares the effect of gradation on CSL. The results show that the initial gradation significantly affects
the critical void ratio of coarse-grained soils but has little effect on the critical stress ratio. Different gradations cause the CSL in
the e-(p'/pa) plane to translation and rotate, whereas in the esk-(p'/pa) plane, the CSL converges to a single curve. A linear
relationship exists between the parameter b of the skeleton void ratio and the fractal dimension D, and the parameters a = 0.13
and b = -1.5 are applicable to most coarse-grained soils. This finding will simplify the application of the skeleton void ratio. The
unified CSL equation proposed in this study provides a good foundation for developing state-dependent constitutive models.
Key Words
coarse-grained soil; CSL; gradation; skeleton void ratio; triaxial test
Address
Feng Gao and Jungao Zhu: Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University,
01 Xikang Road, Nanjing 210098, China
Tao Wang: School of Earth Sciences and Engineering, Nanjing University, 163 Xianlin Road, Nanjing 210023, China
Qixun Luo and Xiaoan Wang: Chengdu Engineering Corporation Limited, Power China. Chengdu, Sichuan 610072, China
Lei Pan: Shanghai research institute of building sciences co..Ltd. Shanghai 200032, China
Abstract
Nanostructures are generally used in environments where they can be subjected to different types of loading;
understanding and determining their reaction to a hygro-thermo-mechanical environment is crucial for their design. This
analysis's main objective is to evaluate the buckling sensitivity of sandwich nanoplates of FGMs subjected to a hygrothermomechanical
loading while resting on a two-parameter elastic medium. To accomplish this investigation, a quasi-3D highshear
deformation theory involving five variables containing integral terms, including the nonlocal elasticity theory of Eringen,
is used. The assumed sandwich nanoplate is placed on an elastic medium, submitted to multiple boundary conditions, and
subjected to a hygro-thermo-mechanical stress. The sandwich nameplate's material properties are intended to be continuously
graded across its whole thickness. An elastic foundation with two parameters is used to model the elastic environment. The
equilibrium equations are constructed using the concept of virtual displacements, and the solution is displayed for several
boundary conditions. The obtained outcomes are approved and validated by comparison with those found by other scholars
discussing the same topic in the literature. The impact and influence of various parameters on the stability of FGM sandwich
nanoplates in a hygro-thermomechanical situation are investigated through the intermediary of parametric analysis.
Key Words
buckling; elastic foundation; Eringen; hygro-thermo-mechanical; nanoplates; nanostructures
Address
Hayat Benachi: Department of Civil Engineering, Faculty of Science and Technology, Abbès Laghrour University, Khenchela, Algeria;
Laboratoire d'Ingénierie et Sciences des Matériaux Avancés, Abbès Laghrour University, Khenchela, Algeria
Abderrahmane Menasria, Abdelhakim Bouhadra, Mohamed Ali Rachedi and Belgacem Mamen: Department of Civil Engineering, Faculty of Science and Technology, Abbès Laghrour University, Khenchela, Algeria;
Material and Hydrology Laboratory, University of Sidi Bel Abbes, Faculty of Technology, Civil Engineering Department, Algeria
Mourad Chitour: Department of Mechanic Engineering, Faculty of Science and Technology, Abbès Laghrour University, Khenchela, Algeria
Abdelouahed Tounsi: Material and Hydrology Laboratory, University of Sidi Bel Abbes, Faculty of Technology, Civil Engineering Department, Algeria;
Department of Civil and Environmental Engineering, King Fahd University of Petroleum & Minerals,
31261 Dhahran, Eastern Province, Saudi Arabia
Abstract
Coral reef limestone (CRL) exhibits varying sedimentary facies, rock structures, and lithologies at different depths,
posing challenges for island engineering construction. This study investigates deformation characteristics of surrounding rock
during tunnel excavation in soft-hard interlayered CRL stratum. A novel method for preparing heterogeneous analog materials
with prefabricated pores is developed to simulate soft and hard CRL interlayers. Physical model tests under two working
conditions examine displacement and stress variations during tunnel excavation. Numerical simulations are subsequently
conducted to verify test validity and assess stratum distribution impacts. Key findings include: (1) Prefabricated pore structures
effectively replicate CRL's natural heterogeneity. (2) Upper-soft/lower-hard stratum induces significant vault displacement (2.35
mm) and stress concentration (0.82 MPa) due to soft rock compression. (3) Upper-hard/lower-soft configurations cause
pronounced arch foot deformation (3.12 mm) from soft rock yielding under overlying hard stratum. (4) Support systems reduce
displacements by 14.8% (lining alone) and 33.3% (combined lining-anchor), with enhanced effectiveness in soft CRL. The
integrated experimental-numerical approach provides critical insights for tunnel design in heterogeneous CRL formations,
demonstrating that support optimization should prioritize lithological interfaces and stress redistribution patterns characteristic of
interlayered systems.
Key Words
coral reef limestone; similar material with pores; soft and hard interlayer; surrounding rock stability; tunnel
excavation
Address
Xiangyu Zhang, Lewen Zhang and Jing Wu: Institute of Marine Science and Technology, Shandong University, Qingdao 266237, Shandong, China
Fuqiang Li: The Third Exploration Team of Shandong Coalfield Geologic Bureau, Taian 271000, China
Wenjuan Wu: Shandong Transportation Institute, Jinan 250102, China
Abstract
Screw piles, which is one of the ground improvement methods, are finding more place in practice day by day. For
this reason, there is a need for studies to investigate the behavior of screw piles under compressive and uplift loads. In this
context, the behavior of screw piles with different number of helixes in groups was investigated with different number of screws
and group patterns. To evaluate behavior of screw piles, settlement ratios, group efficiency and helix number efficiency values
were calculated by using finite element method. Based on an experimental study from the literature, modelling was performed
on PLAXIS 3D, which works with the finite element method, and the results were matched. As a result of this study, it was
observed that increasing the number of helixes increased the bearing capacity under both compressive and uplift forces. In
addition, it was determined that group efficacy values changed in different patterns and different number of pile groups.
Optimum screw pile type for group patterns also differs for different load conditions. The modelling results were visualized and
were found to match with the failure surfaces reported in the literature. It was suggested that optimum helix number and group
pattern for screw pile applications can be achieved with evaluating settlement and efficiency values together.
Key Words
compressive forces; finite element method; ground improvement; screw piles; uplift forces
Address
Talha Sarici and Mustafa Ozcan: Department of Civil Engineering, Inonu University, 44310, Malatya, Türkiye
Abstract
In the era of big data, enhancing the reliability of large-scale geotechnical datasets is crucial for accurate subsurface
characterization. Although various statistical interpolation techniques have been developed, significant challenges remain in
addressing spatial variability and uncertainty inherent in subsurface conditions. This study presents an advanced spatial
interpolation framework that integrates carefully preprocessed borehole datasets with adaptive grid-based modeling to improve
the precision of subsurface mapping. The borehole data were classified based on elevation discrepancies from a Digital
Elevation Model (DEM), temporally segmented by project year and type, and standardized using the 3-sigma rule to minimize
outlier-driven distortions. The interpolation process combined kriging with localized averaging strategies and systematically
varied grid resolutions to assess performance sensitivity. Leave-one-out cross-validation, using geological layer thickness as the
reference metric, demonstrated that finer grids significantly reduced interpolation error near the surface, while deeper layers
exhibited increased uncertainty. Notably, the implementation of an adaptive grid system, capable of dynamically adjusting
spatial resolution according to data density and terrain complexity, proved essential in mitigating the smoothing effect often
associated with kriging. Furthermore, in data-sparse regions, the integration of localized averaging within adaptive cells helped
stabilize estimation accuracy. This adaptive approach offers a powerful enhancement to conventional spatial modeling
techniques by enabling more faithful representation of geological heterogeneity and by reinforcing the robustness of predictions
under variable data availability, ultimately contributing to more informed geotechnical decision-making.
Key Words
boring investigation; digital twin; geospatial interpolation; geotechnical database; outlier analysis;
subsurface information
Address
Taek-Kyu Chung and Choong-Ki Chung: Department of Civil and Environmental Engineering, Seoul National University, 1, Gwanak-ro, Gwanak-gu,
Seoul 08826, Republic of Korea
Han-Saem Kim: Department of Civil and Environmental Engineering, Dongguk University, 30, Pildong-ro 1-gil, Jung-gu,
Seoul 04620, Republic of Korea
Chang-Guk Sun: Earthquake Research Center, Korea Institute of Geoscience and Mineral Resources, 124,
Gwahak ro, Yuseong gu, Daejeon 34132, Republic of Korea
