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Research Article
Inferences About Geographical Awareness and Map Representations in Early Japan
Kaoru Yoshida*
Issue:
Volume 14, Issue 2, April 2026
Pages:
46-55
Received:
9 February 2026
Accepted:
24 February 2026
Published:
5 March 2026
Abstract: The methods by which territorial extent was understood in early Japan, spanning from the Yayoi period (third century BC–third century AD) to the Kofun period (third–seventh century AD) remain largely unknown. Nevertheless, it is likely that a certain level of geographical knowledge was necessary for interregional negotiation and the subsequent processes of political consolidation. Spatial patterns can be observed in the distribution of archaeological sites and prominent mountains. For example, when major ruins in the former Izumo Province, where numerous bronze artifacts have been excavated, are geographically linked with peaks such as Mt. Daisen and Mt. Sanbe, emerges as an approximately large-scale isosceles triangular configuration. Similarly, connecting Mt. Fuji, Mt. Daisen, and Mt. Takachiho—three of Japan’s most distinctive landmarks—also produces an enormous triangular arrangement. These triangular groupings are further associated with shared mythological traditions, which may suggest that a broad geographical awareness existed during this early period. Although definitive conclusions cannot yet be drawn from surviving records or material evidence, this study presents the relative spatial relationships among key mountains and archaeological sites. In addition, as an exploratory reconstruction, the Japanese archipelago is represented using a stick chart (branch-type map), a primitive cartographic form in order to examine possible modes of early geographical perception.
Abstract: The methods by which territorial extent was understood in early Japan, spanning from the Yayoi period (third century BC–third century AD) to the Kofun period (third–seventh century AD) remain largely unknown. Nevertheless, it is likely that a certain level of geographical knowledge was necessary for interregional negotiation and the subsequent proc...
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Research Article
FEM Study of Double-slab Tank Foundations with and Without Bottom Slab Slits Considering Seismic Effect and Soil Structure Interaction
Vijay Kumar Khanna*
Issue:
Volume 14, Issue 2, April 2026
Pages:
56-66
Received:
20 February 2026
Accepted:
13 March 2026
Published:
26 March 2026
DOI:
10.11648/j.ajce.20261402.12
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Abstract: More than four decades ago, a double-slab reinforced concrete foundation concept for large-diameter steel storage tanks incorporating orthogonal slits in the bottom slab was proposed but not adopted because of concerns regarding structural continuity and seismic performance. With advances in finite element modelling and soil–structure interaction analysis, the structural behaviour of such an articulated foundation system can now be re-examined. This study compares two foundation configurations: (A) a conventional monolithic double-slab foundation and (B) a slitted configuration in which full-depth orthogonal slits are introduced in the bottom slab and connected through shear dowels. Three-dimensional finite element models are developed using solid elements to represent the concrete components and Winkler-type elastic springs to simulate soil support. The analysed system represents a 58 m diameter storage tank foundation subjected to a uniform pressure load of 150 kPa together with a horizontal seismic acceleration of 0.25 g. The complete structural system is modelled as one combined unit and analysed. The results indicate that the slitted configuration reduces peak soil contact pressure from approximately 210 kPa to 185 kPa, resulting in a more uniform pressure distribution under static loading. However, the associated reduction in global stiffness increases vertical deflection from 18.2 mm to 19.1 mm under static load and from 23.75 mm to 25mm under seismic loading. Stress concentrations are also observed near slit–dowel interfaces under seismic excitation. The findings demonstrate that controlled articulation of foundation slabs can modify load-transfer mechanisms and soil pressure behaviour, although its application requires careful detailing and consideration of seismic effects. The study provides analytical insight into articulated tank foundation systems and establishes a rational framework for evaluating such configurations within performance-based foundation design.
Abstract: More than four decades ago, a double-slab reinforced concrete foundation concept for large-diameter steel storage tanks incorporating orthogonal slits in the bottom slab was proposed but not adopted because of concerns regarding structural continuity and seismic performance. With advances in finite element modelling and soil–structure interaction a...
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Research Article
Reliability-Based Slope Stability Analysis Along the
Bonga-Felegeselam Road, Ethiopia
Issue:
Volume 14, Issue 2, April 2026
Pages:
67-81
Received:
26 February 2026
Accepted:
9 March 2026
Published:
27 March 2026
DOI:
10.11648/j.ajce.20261402.13
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Views:
Abstract: Slope instability is a common problem in mountainous road corridors, particularly in regions characterized by steep terrain, weak soil formations, and intense seasonal rainfall. The Bonga-Felegeselam road in southwestern Ethiopia has experienced several slope failures during construction due to these unfavorable geological and hydrological conditions. This study investigates the causes of instability and evaluates appropriate stabilization measures for two critical cut slopes located between Stations 16+900 to 16+980 (left-hand side, LHS) and Stations 35+200 to 35+300 (both LHS and RHS) of LOT I: Bonga Asphalt Road Project. Detailed site characterization was conducted through field observations, geometric configuration, soil classification, and laboratory testing to determine the relevant geotechnical properties. Slope stability was assessed using both deterministic and probabilistic approaches based on the Limit Equilibrium Method (LEM) and the Finite Element Method (FEM). The analyses considered different groundwater conditions to evaluate the influence of rainfall-induced saturation on slope stability. The results indicate that the slopes become highly unstable under fully saturated conditions, with factors of safety ranging from 0.657 to 0.916 and failure probabilities between 41.8% and 95.3%. Sensitivity analysis further showed that slope stability is more sensitive to variations in the friction angle than cohesion. To mitigate the instability, a combination of masonry retaining walls, surface drainage, and subsurface drainage systems was proposed. Post-remediation analyses demonstrated a significant improvement in slope stability, increasing the factor of safety to values between 1.57 and 1.90. The findings highlight the importance of integrating deterministic and probabilistic approaches to develop reliable stabilization strategies for rainfall-prone mountainous regions.
Abstract: Slope instability is a common problem in mountainous road corridors, particularly in regions characterized by steep terrain, weak soil formations, and intense seasonal rainfall. The Bonga-Felegeselam road in southwestern Ethiopia has experienced several slope failures during construction due to these unfavorable geological and hydrological conditio...
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Research Article
Structural Behavior of Concrete Retaining Walls with Shear Keys at Different Positions
Issue:
Volume 14, Issue 2, April 2026
Pages:
82-94
Received:
16 February 2026
Accepted:
3 March 2026
Published:
28 March 2026
DOI:
10.11648/j.ajce.20261402.14
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Views:
Abstract: This study investigates the structural behavior of reinforced concrete cantilever retaining walls incorporating shear keys under static loading conditions using three-dimensional finite element analysis in ANSYS Workbench. The primary objective was to evaluate the influence of shear key provision on stability parameters such as sliding resistance, deformation, strain distribution, and stress concentration. A retaining wall of 4.0 m height and 2.4 m base width was modeled under active earth pressure of 48 kN calculated using Rankine’s theory. The baseline model without a shear key was found to be safe against overturning (Factor of safety = 2.97) but unsafe against sliding (FS = 1.26 < 1.5). Finite element results showed maximum equivalent strain of 0.04032 mm/mm, deformation of 5.7 mm, normal stress of 2.4 × 10⁷ Pa, and shear stress of 8 × 10⁶ Pa. The introduction of a shear key significantly improved performance, reducing strain to 0.00488 mm/mm and deformation to 4.2 mm. Further enhancement with bolted shear key configuration yielded the lowest strain (0.003629 mm/mm), deformation (3.8 mm), normal stress (1.15 × 10⁷ Pa), and shear stress (1.5 × 10⁶ Pa). The findings confirm that shear key incorporation effectively enhances sliding resistance, improves stress redistribution, and increases overall structural stability, providing a safer and more economical retaining wall design solution.
Abstract: This study investigates the structural behavior of reinforced concrete cantilever retaining walls incorporating shear keys under static loading conditions using three-dimensional finite element analysis in ANSYS Workbench. The primary objective was to evaluate the influence of shear key provision on stability parameters such as sliding resistance, ...
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