World Academy of Science, Engineering and Technology

Authors: Xueying Yang, Weiming Gong

Abstract:

Weakly cemented gravel-bearing sandstone is a special kind of rock with great variability in mechanical properties, and the relevant specifications have not specified it in detail. In-situ testing is the most effective method to reveal the mechanical properties of weakly cemented gravel sandstone. According to the field in-situ test method of rock and soil in the relevant specifications, with the Longtan Bridge North Anchor Foundation Pit Project as the actual background, field tests on the shear strength and bearing capacity of the weakly cemented gravel-bearing sandstone of the anchorage base were carried out, and the bedrock- The in-situ data of the frictional resistance and bearing capacity of the concrete test block contact surface, and the test results provide data support for verifying the design and studying the mechanical properties of weakly cemented gravel sandstone.

Keywords: weakly cemented gravel sandstone, basement test, bearing capacity, bridge engineering, suspension bridge, anchorage

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Authors: Adarsh Singh, Gobinda Das, Sreyashrao Surapreddi, Priyanka Ghosh

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This study presents an integrated experimental and artificial neural network (ANN) based modeling approach to assess the effectiveness of open barrier (OB) in mitigating ground borne vibrations along multiple directions relative to the vibration source. Large scale field block vibration tests are conducted to measure the ground vibration responses under both without barrier (WB) and OB conditions along several measurement lines (MLs), including the centreline and radial lines inclined at 15ο and 20ο on either side of the centreline. The vibration isolation performance of OB is evaluated using amplitude reduction ratio (ARR) and isolation efficiency (IE) derived from the experimental results. The study further investigates the influence of key parameters such as excitation frequency (f) and source barrier distance (Sb) on the effectiveness of OB. In addition, an ANN model is developed and trained using the experimental results, offering a reliable and efficient predictive tool for anticipating the performance of OB along various MLs, particularly valuable in scenarios where the conventional experimental investigation is not feasible.

Keywords: machine foundation, open barrier, amplitude reduction factor, isolation efficiency, artificial neural network

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Authors: Gobinda Das, Adarsh Singh, Priyanka Ghosh

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Machine foundations play an essential role in providing structural support to heavy industrial equipment while mitigating the transmission of vibrations to surrounding structures. In many industrial applications, spatial limitations often necessitate the placement of machine foundations in close proximity, leading to dynamic interaction effects that can significantly alter the vibratory response of the system. Hence, it becomes essential to account for such dynamic interference between machine foundations to mitigate the risks of resonance, amplified vibrations, and consequent harm to both machinery and supporting structures. To address this challenge, the present study numerically investigates the dynamic response of two closely spaced machine foundations resting on both unreinforced and geocell-reinforced soil beds. A three-dimensional (3D) finite element (FE) analysis is performed using the commercially available ABAQUS software, considering a configuration of two closely spaced square footings, where one footing (active footing) is subjected to harmonic loading, while the adjacent footing (passive footing) is loaded statically. The steady-state vibrational responses of both footings are analyzed to quantify the dynamic interaction between them, considering both unreinforced and reinforced conditions. The effectiveness of geocell reinforcement in controlling the dynamic interference between the footings is systematically evaluated. Additionally, the influence of crucial aspects such as loading frequency (f) and footing spacing (S) on the dynamic interaction is examined.

Keywords: machine foundation, dynamic interference, finite element analysis, geosynthetics

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Authors: Salama Omar Ahmad Alosman, Ali Firat Cabalar, Muge Akin

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AbstractThis study assesses the liquefaction potential of multiple boreholes located along the Asi River in Antakya, Türkiye, where the subsurface profile is characterized predominantly by sandy soils with variable stratigraphy and depth. A nonlinear site response analysis was performed using the Deep Soil software to simulate seismic loading and the generation of excess pore water pressure under earthquake shaking. Five representative ground motions were employed in the simulations: the 1999 Kocaeli, 1999 Chi-Chi, 1995 Kobe, 1999 Düzce, and 2023 Kahramanmaraş earthquakes. These motions were selected for their varying magnitudes, frequency content, and relevance to regional seismicity. he dynamic response of each borehole was analyzed under these motions, enabling the calculation of key liquefaction-related parameters, including shear strain, pore pressure ratio, and factor of safety (FS). A comparative interpretation of the DeepSoil outputs and the TBDY-2018 code-based results was carried out. This dual-method approach revealed consistent patterns of liquefiable layers in certain depth intervals, but also underscored notable differences in liquefaction prediction, particularly in zones with nonlinear stress-strain behavior and high pore pressure build-up. The findings demonstrate the value of combining numerical simulations with codified assessments to improve the reliability of liquefaction hazard evaluations in complex alluvial basins.

Keywords: liquefaction, deep soil program, seismic analysis, pore water pressure

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Authors: Mirza Aamir Baig, Nazrul Islam

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The damage induced by near-field fling-step earthquakes with the characteristics of permanent static ground offsets in the time history of displacement was examined numerically using a four-span steel box girder bridge. The goal of this research is to determine how near-fault fling-step ground vibrations influence steel box girder bridges and to provide a method to determine how sensitive bridges are near active faults. Near-field fling-step ground motion records from the Chi-Chi earthquake were employed to develop seismic damage curves and a probabilistic damage model for the bridge. Utilizing incremental dynamic analysis (IDA), the bridge’s performance was assessed across varying damage states, offering valuable insights into its vulnerability under intense seismic excitations. Bridge fragility curves and damage models are created using damage metrics such as ductility and girder displacement with peak ground acceleration (PGA) as an intensity measure. The study indicates that median spectral acceleration that caused different levels of earthquake damage was higher for the fling-step records after the PGA level of 0.4g. The results were significantly different in the case of fling-step recordings, increasing the likelihood of failure at several damage levels, particularly the bar buckling damage state. The findings demonstrated that while designing steel box girder bridges, the fling-step behaviour of the ground motions must be considered.

Keywords: fling step earthquake, seismic response, fragility analysis, plastic hinge, ductility

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Authors: Shreeja Kacker, Nazrul Islam

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This paper presents the design and analysis of a bolted intra-modular steel connection tailored for modular construction. The proposed joint connects ISMB beams to a rectangular hollow section (RHS) column using end plates and a welded top cover plate, simulating a realistic modular interface. The joint was modeled in IDEA StatiCa and evaluated under combined axial force and bending moments, adhering to IS 800 and relevant Indian standards. Various design parameters such as bolt configuration, plate thickness, weld size, and steel grade were optimized for strength and fabrication simplicity. The results demonstrate that the connection safely withstands the applied loads without excessive deformation or local failure. Its standardized detailing and structural reliability make it a viable solution for repetitive, high-rise modular steel buildings.

Keywords: modular construction, bolted connection, RHS column, IDEA StatiCa, IS 800, intra-modular joint, steel structures, high-rise buildings

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Authors: Abdelkhalek Barbouchi, Rachid Idouhli, Mohy-eddine Khadiri, Intissar Benzakour, Jaouad Benzakour

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The extraction of gold (Au) from refractory ores poses major challenges due to the inclusion of gold particles in sulfide minerals. In this study, an alternative and highly efficient oxidative pretreatment for refractory gold ores and concentrates was developed using a persulfate-based advanced oxidation process. This approach generates strong oxidizing radicals to oxidize sulfide minerals, thereby releasing the enclosed gold. For the studied gold concentrate, the extraction of gold by direct cyanidation reached only a yield of 62.6%. The refractoriness behavior behind this performance has been examined using diagnostic leaching and mineralogical characterization using an automated Scanning Electron Microscope (SEM) coupled with Energy Dispersive X-ray (EDX), and it was attributed to encapsulation of fine particles of gold within sulfide minerals, mainly pyrite and arsenopyrite. To oxidize these sulfides by persulfate, four activation modes were examined to generate reactive radicals: ultraviolet (UV) activation, ultrasound (US) activation, thermal (T) activation and Ag+ and Fe2+ catalysts. The experimental results showed that UV and US methods are more efficient in generating reactive radicals, and the removal efficiency of Fe, As and S, as well as the subsequent gold extraction by cyanidation, varied in the following order: UV > US > T > Ag+ > Fe2+. The identification tests via utilization of phenol and nitrobenzene chemical probes revealed that the oxidizing radicals predominant and responsible for the oxidation of pyrite and arsenopyrite are sulfate radicals (SO_4^(•-)) and hydroxyl radicals (OH•). These radicals are generated more effectively through UV and US activation modes. The US activation resulted in a gold extraction of 86.4%, while UV activation achieved a slightly higher extraction of 88.1%. The findings also showed that combining UV with Ag⁺ catalyst, US with heating at 80 °C, and US with heating at 80 °C in the presence of an Ag⁺ catalyst resulted in gold extractions of 91.1%, 92.2%, and 93.6%, respectively. The results led to proposing a possible mechanism for the oxidation of sulfide minerals during the pretreatment process.

Keywords: refractory gold concentrate, oxidative pretreatment, advanced oxidation processes, persulfate activation, radicals

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Authors: Mohamed Yacine Kheliouen

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In 2003, northern Algeria was struck by a magnitude 6.8 earthquake, causing significant human and material losses. In response to this tragedy, authorities have adopted a policy aimed at regulating land use and preventing risks while ensuring effective disaster management within a sustainable development framework. This initiative made the integration of seismic risks into urban planning and development processes imperative. In this context, this study focuses on evaluating the capacity of urban infrastructure, particularly road networks and open spaces (non-built areas), to effectively respond to evacuation and rescue needs in the aftermath of a destructive earthquake. The proposed method was implemented by the Japan International Cooperation Agency (JICA) and the Algerian Center for Applied Research in Earthquake Engineering (CGS) as part of the micro-seismic zoning study of the city of Algiers. In our study, the ‘Emergency Evacuation and Rescue Facilities’ criterion was applied to the city of Dellys as a tool for assessing the road network and open spaces. The analysis utilized Geographic Information System (GIS) data based on experimental indices developed in Japan. The evaluation presents vulnerability maps that identify urban areas most susceptible to accessibility challenges for evacuation and rescue operations in the event of an earthquake. The article provides managers with the tools to reduce the city's vulnerability through preventive measures, such as establishing refuge zones for disaster victims and widening streets to facilitate the passage of rescuers in vulnerable areas prior to the occurrence of an earthquake. To the authors' knowledge, this article is the first to present an evaluation of road networks and open spaces in relation to seismic risk in the studied region. It highlights the critical importance of urban resilience in mitigating human and material losses during a destructive earthquake.

Keywords: dellys, evaluable urban road, evaluable urban area, vulnerability map

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Authors: Jayamohan J., Yathee Sree Perumal

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Reinforced Granular Beds are often used to support foundations on weak soils and low-lying areas. But now granular soils have become very scarce, and it makes the reinforced soil technique uneconomical. The cost-effective option is to reinforce the locally available soil with suitable geosynthetics. But the effectiveness of reinforcement embedded in clayey soil is very less when compared with granular soil. This paper investigates the possibility of reinforcing the locally available clayey soil with a geogrid embedded in a thin layer of sand by carrying out a series of finite element analyses and large-scale direct shear tests. The parameters studied are the effects of the thickness of the thin granular layer and its depth below the base of the footing. The results of the finite element analyses indicate that the bearing capacity of clay can be improved considerably by reinforcing with a geogrid embedded in a thin layer of sand. It is also observed that the bearing capacity increases with the thickness of the sand layer. From the results of large-scale direct shear tests, it is observed that the shear strength of clay reinforced with geogrid encapsulated in a thin layer of sand is better than reinforced sand and reinforced clay.

Keywords: clay, geogrid, finite element analysis, bearing capacity, large scale direct shear test

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Authors: Arturo Maldonado

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The shear strength of bedding planes within shales materials is an essential input for slope stability analysis of the open pits of the Pilbara. This paper presents the outcomes of doctoral research where the bedding partings were classified based on surface conditions and analyzed using laboratory direct shear testing of both natural and artificial partings. Both datasets support a conceptual model, where bedding surface conditions change with weathering progression: in fresh shales, bedding partings are mostly in rock-to-rock contact, whereas when shales become weathered, slightly, moderately, and highly weathered, the shale material itself have experienced a sufficient chemical degradation enabling the bedding surfaces to behave similar to filled defects, and remarkably, the basic friction angles of bedding partings appear to relate well to the dominant mineralogy of these surfaces. This paper presents the relationships between dominant mineralogy types and non-dilation friction angles of weathered bedding surfaces

Keywords: shear strength, bedding planes, basic friction, mineralogy, spectral scanning

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Authors: Arash Nazari Rad, Peter Sharifi

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In this paper, we compare the performance-based design Solution and the Deemed-to-Satisfy Solution for seismic retrofitting of Mechanical, Electrical, Plumbing and Fire system (MEP-F) components in existing buildings. The comparison focuses on the application of these Solutions in areas with low seismic hazards, such as Australia. The performance-based design Solution is evaluated for its flexibility and detailed assessment approach, while the Deemed-to-Satisfy Solution is assessed for its simplicity and standardised procedures. Recommendations are provided on the suitability of each Solution for low-risk areas, highlighting their respective advantages and limitations. Also, this paper compares the seismic bracing design for mechanical, electrical, and plumbing (MEP-F) systems in new versus existing buildings, focusing on assessing existing conditions, integration with structural elements, space constraints, structural limitations, minimizing disruption, code compliance, and cost considerations. It highlights the unique challenges and strategies required for retrofitting existing buildings while emphasizing the advantages of incorporating seismic bracing in new constructions. Finally, this study outlines key seismic design recommendations for effectively integrating mechanical, electrical, and plumbing systems between existing and new buildings, addressing challenges such as compatibility, space constraints, and safety measures, with recommendations based on the authors' experiences.

Keywords: MEP-F (mechanical, electrical, plumbing and fire system), performance-based design (PBD), seismic retrofit, existing building

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Authors: Hector E. Garcia, Mehrdad Razavi

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This study investigates the influence of stress concentration due to variations in the specimen contact area on Kaolinite soil specimens' unconfined compressive strength (UCS). A 3D scanning technique assessed the surface geometry of cylindrical specimens subjected to different contact conditions. Finite element modeling (FEM) was used to evaluate stress distribution, complementing laboratory UCS tests. The results indicate that specimens with reduced contact area experience significant stress concentrations, leading to variations in UCS. Furthermore, the study found that asymmetry in the contact area introduces unbalanced moments, which further influence stress distribution and failure patterns. Combining experimental and numerical approaches provides a comprehensive understanding of how stress concentration affects soil strength.

Keywords: 3D scanning, failure patterns, finite element modeling, specimen contact area, stress concentration, unconfined compressive strength

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Authors: Nichirvan Ramadhan Taher, Hüseyin Suha Aksoy, Mesut Gör

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Enormous quantities of discarded waste polyethylene terephthalate (PET) bottles are annually deposited worldwide. Despite the vast disposal of these bottles, their inherent qualities have the potential to be beneficial in engineering projects, particularly in enhancing the shear properties of soil. This study explores the influence of incorporating recycled PET flakes on the shear strength properties of sandy soil. The sandy soil was reinforced using varying percentages of recycled PET flakes, including 0.0%, 0.5%, 0.75%, 1.0%, and 1.5% by the dry weight of the sand. Shear strength properties of sand were investigated by conducting a series of direct shear box tests for unreinforced sand and reinforced sand with different percentages of PET flakes under three different normal stresses. All specimens of the shear box test were prepared at three distinct relative densities: Dr = 40%, 65%, and 85%. After assessing the shear strength properties of sand reinforced with various percentages of recycled PET flakes through a direct shear box test, the shear characteristics of both the unreinforced sand and the sand enhanced with PET flakes were determined. The findings indicated that the optimal percentage of PET flakes, providing the greatest enhancement to sandy soil, is 0.75%. Beyond this threshold, there is a decline in the shear strength properties of the sandy soil.

Keywords: recycled PET flakes, sandy soil reinforcement, relative densities, soil improvement

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Authors: Xueying Yang, Weiming Gong

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Bridge construction in China is gradually moving towards the direction of long span, and the volume of anchor foundations is also increasing with the continuous increase of suspension bridge span. In this paper, the anchorage on the north bank of Yanji Yangtze River Bridge is taken as the research object, and the selected foundation types are mainly the caisson foundation and underground diaphragm wall foundation. Considering the construction risk, the safety of surrounding buildings and levees and the space requirement of the anchoring system, the underground diaphragm wall foundation scheme is recommended. Based on the comparative analysis of the anchoring methods of Huanggang side anchorage, it can be seen that the longitudinal 8-figure underground diaphragm wall foundation scheme has obvious advantages in the total square amount of anchoring concrete and the land area, and the base stress is more uniform. By comparing and analyzing the scheme of the underground diaphragm wall and the scheme of the large diameter retaining pile and milling joint wall, the mature scheme of the underground diaphragm wall foundation is recommended. The study of scheme comparison and selection in this paper, it can provide a useful reference for bridge design under similar conditions in the future. The new type of ‘8’ underground diaphragm wall gravity anchorage foundation finally determined in this paper will also get great attention and promotion.

Keywords: long-span suspension bridge, anchorage foundation, scheme selection, underground diaphragm wall

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Authors: Xueying Yang, Wenni Deng

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At present, for gravity anchor foundations located on rock foundations, anti-slip structures are often set in the base to improve the horizontal tension resistance of the foundation. This paper explores the load-bearing characteristics of Ezhou side anchor foundation under self-weight stress and cable force under two working conditions by numerical simulation and theoretical calculation using the six-spring method. It is found that the horizontal displacement of the foundation decreases gradually from the cable point to the bottom of the foundation, and the vertical settlement displacement decreases gradually from the front surface of the foundation to the back surface. The six-spring model is in good agreement with the numerical simulation results for the calculation results of the horizontal displacement of the foundation. Under the action of cable force, ignoring the horizontal soil resistance in front of the foundation will result in a lot of engineering waste, and the conclusion that the anti-sliding structure contributes a lot to the horizontal soil resistance of the foundation is provided. When setting the anti-slip structure, it should be based on the distribution of the local bedrock soil layer, and the anti-slip structure should be set in the hard rock layer as far as possible to play a better role. Because bridge engineering has the basic characteristics of long construction time, high investment and long service period, the project has great economic and social benefits in the promotion and application of rock foundation anti-slip structure.

Keywords: extended foundation, anti-slip structure, bearing characteristics, numerical simulation

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Authors: Xueying Yang, Wenni Deng

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In the central and western regions where soft rock geology is common in China, arch bridges have always been the main bridge type selection. The arch foundation adopts a step structure with large overall stiffness, which can save the cost of infrastructure construction while meeting the requirements of bearing deformation. Based on the foundation project of Lantian Yangtze River Five Bridges in Luzhou, this paper analyzes the bearing capacity of the step-type block foundation in soft rock stratum, and proposes a rigid-flexible judgment method and a standard-based optimization C method for stress displacement calculation. The calculation formula of local shear failure angle is proposed, the shear failure law is analyzed, the checking calculation of foundation deformation characteristics is optimized. The bearing performance analysis system of the step-type block foundation with high engineering applicability is formed. Research conclusions: The rigid-flexible judgment and the optimization specification C method can be applied to the bearing capacity analysis of the stepped block arch foundation in soft rock, and the foundation should be rigid under the design standard of displacement control. In the new calculation model, the output results, especially the displacement value, are not limited to single dimension, which can reflect the distribution of foundation stress and displacement within a certain range. The optimization specification C method has higher accuracy in calculation, and the relative error is 34 % lower than that of the specification method, which has better applicability and reliability. When the overall horizontal slip of the arch occurs, the local shear failure may occur in the front rock mass of the step block foundation. The different design sizes of the step-type block foundation correspond to four different failure modes, which should be reasonably designed according to the failure angle. The bearing capacity and displacement control values of the foundation are used to complete the bearing performance analysis. The design scheme of the arch bridge foundation meets the bearing requirements, and the deformation performance still has a large space to be optimized. Through the calculation of engineering examples, it is shown that the single-dimensional bearing performance checking results are generally safe.

Keywords: step-type block, soft rock foundation, bearing capacity, local shear failure, stiffness judgment

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Authors: Xueying Yang, He Yang, Weiming Gong

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Luzhou Lantian Yangtze River Bridge No. 5, located in Luzhou City, Sichuan Province, is a steel box arch bridge with a total length of 612m and a net span of 570m. Given its record-setting main arch span in China, the design had to address the structural challenges of the large-span arch ring and the significant thrust from the arch ribs. Consequently, the stepped arch foundation on the north bank became a key research focus. This study used PLAXIS 3D to model and analyze the failure modes of the stepped foundation under various loads. Results showed that the most critical condition for the north bank foundation was the minimum bending moment combination, with maximum settlement at 0.117mm and maximum horizontal displacement at 0.234mm, both within acceptable limits. Under ultimate failure conditions, the foundation experienced local shear failure under pure horizontal loads, with decreasing failure displacements as horizontal load ratios decreased. When H: V: M = 1.75:1:1, the foundation steps formed a sliding surface with the rock base, leading to overall shear failure away from the river surface. Based on these findings, the north bank foundation structure can be optimized. Through the engineering example calculation, it is shown that the single-dimension bearing performance checking results are generally safe, and the H-V-M envelope surface can well cope with the analysis of arch foundation under complex working conditions, and it is also the trend of future bearing performance analysis and research.

Keywords: numerical simulation, arch foundation, load-bearing characteristics, ultimate failure

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Authors: Yang Xueying, Yang He, Gong Weiming

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Although borehole investigation and field tests can minimize interference with undisturbed soil or rock mass, ensuring that measured values have high authenticity and reliability, discrepancies still arise when directly applying these results to the design calculations of large-scale projects. Conventional codes and calculation methods are typically used for soil foundations and regular block foundations. For the structural design and size optimization of stepped block foundations in soft rock foundations, conducting load-bearing performance analysis remains a pressing challenge. This paper addressed this issue by examining the interaction between block structure and soft rock foundations in the context of the world's largest span arch bridge project under construction. Using the influence circle of additional stress, the study revealed that foundation size effects manifest in the correction of foundation stiffness. Through theoretical analysis, the power function formula was established, and parameters a and β were refined using the finite element method. This enhanced the applicability of the mathematical model for interaction, leading to the proposal of a basic dimensional effect expression suitable for this project. Verification through engineering examples demonstrated that this approach effectively reduced the maximum calculation error in stress-displacement calculations by nearly 70%, providing valuable engineering reference.

Keywords: size effect, foundation stiffness, theoretical formula, numerical simulation

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Authors: Eslam M. Hemid, Daniel Barreto, Vasiliki Dimitriadi, J. Benral-Sanchez

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Soil plugging is a significant phenomenon influencing the behaviour and load-bearing capacity of open-ended piles driven into sandy soils. During pile installation, soil may be forced into the pile, forming a plug that alters the pile-soil interaction and affects the load transfer mechanism. This study investigates the soil plug formation in scaled-down open-ended piles driven into fine, medium, and coarse sand. A series of experimental tests were conducted to evaluate the impact of relative density, particle size distribution (PSD), penetration depth, driving rate, and pile geometry on soil plugging. The degree of plugging was quantified using the Plug Length Ratio (PLR) and Incremental Filling Ratio (IFR), providing insights into the extent of soil intrusion and its variation with different test conditions. The results demonstrate that sand properties, pile geometry, and driving energy significantly influence the formation mechanism of soil plugs. Understanding these factors is critical for optimizing pile design and improving predictions of axial capacity in offshore and onshore foundation applications.

Keywords: bearing capacity, IFR, PLR, soil plugging

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Authors: Prabu Thannasi, Mohmed Shakeel Abid, Chandru Pichaimuthu

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Deep cement mixing (DCM) and jet grouting are widely employed ground improvement techniques for solidifying soft sediments. The dynamic behavior of cement-fly ash stabilized marine clays remains unknown, mainly due to the scarcity of experimental data. This study investigates the static and dynamic behavior of cement-fly ash-mixed and stabilized Indian marine clay at different strain values using a cyclic triaxial test. The current study presents a series of laboratory investigations to evaluate the unconfined compressive strength (qu), shear wave velocity (Vs), maximum shear modulus (Gmax), shear stiffness or modulus (G), damping ratio (D), and strain-dependent behavior of cement-fly ash mixed Indian marine clay as a function of curing time and binder content. The mechanical properties of the cement-stabilized clay increased due to the formation of the primary reaction product, calcium silicate hydrate (CSH) and ettringite, as analyzed using X-ray diffraction. The generation of this cementitious compound reduced the void space within the clay matrix, resulting in a denser and stronger stabilized clay that aligned with the development of strength and dynamic behavior over time. The findings from this research are expected to contribute to the seismic design and considerations for DCM and jet grouting-treated soft clays in offshore construction applications.

Keywords: marine clay, unconfined compressive strength, cyclic triaxial test, bender element test, shear stiffness, damping ratio

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Authors: Masoumeh Kazemi, Davood Moradkhani, Alireza Abbas Alipour

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This study explores the application of an Artificial Neural Network (ANN) model to predict cake moisture in the pressure filtration process of zinc production. The model considers seven parameters: temperature (35°C and 65°C), solid concentration (0.2 and 0.38 g/L), pH (2, 3.5, and 5), air-blow time (2, 10, and 15 min), cake thickness (14, 20, 26, and 34 mm), pressure, and filtration time. A total of 288 tests were conducted using two fabric types: polypropylene (S1) and polyester (S2). The ANN model's performance was evaluated using the Coefficient of Determination (R²), Mean Square Error (MSE), and Mean Absolute Error (MAE). Results showed R² values of 0.88 and 0.83, MSE values of 6.243×10⁻⁷ and 1.086×10⁻⁶, and MAE values of 0.00056 and 0.00088 for S1 and S2, respectively. These findings demonstrate the ANN model's high accuracy in predicting cake moisture in zinc leaching processes.

Keywords: hydrometallurgy, pressure filtration, machine learning, artificial neural network

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Authors: Hassan Moulay Omar, Abdellah Alem, Armelle Jarno, Saber Imanzadeh, Said Taibi

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Several geotechnical problems involve pavements in Algerian arid regions; most are related to the scarcity of normalized materials and extreme climatic conditions. Numerous research studies have recently been carried out on valorizing local Saharan materials in road construction to compensate for the lack of standard materials. Many open dune sand deposits, available in abundance in the southwest region of Algeria, combined with tuff and quarry waste, are a promising alternative to meet the needs of materials for road construction. In this context, to valorize dune sand available in huge quantities in the region, an optimized formulation is developed based on an appropriate design of experiments. This formulation consists of a mixture of 46% dune sand, 36% tuff, 11% quarry waste and 7% water, and she meets all current standards related to the design of Saharan pavements. This study deals with the hydromechanical behavior of the optimized mixture intended for the construction of pavements. A series of experiments combining compaction and unconfined compressive tests for different water contents, varying from dry to saturated state, have shown the dominant effect of moisture on mechanical behavior. The unconfined compressive strength decreases from 2.46 MPa to 0.13 MPa when the saturation degree increases from 1.17% to 65%. Thus, the influence of water content and degree of saturation on mechanical properties, such as the unconfined compressive strength and strain modulus is explored.

Keywords: valorization, saharan materials, sand dunes, tuff, quarry waste, hydromechanical behavior

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Authors: Yasser H. Altowaijri

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Projected climate change, characterized by increased frequency and intensity of extreme weather events such as flooding, excessive rainfall, and rising temperatures, poses significant risks to the stability and performance of railway earthen dams. This paper provides a comprehensive review and analysis of the expected potential impacts of future climate changes on railway infrastructure, focusing on the design processes outlined in various international railway design codes. The study examines how these evolving climate conditions may affect the structural integrity of railway track foundations and evaluates the adequacy of current design methodologies in mitigating climate-related risks. The results offer critical insights for the railway engineering community, emphasizing the need for adaptive strategies to enhance the resilience of track foundations in the face of changing climate conditions. Furthermore, this paper proposes actionable solutions and design modifications to minimize the adverse effects of climate change, ensuring the long-term sustainability and reliability of railway systems.

Keywords: climate changes, unsaturated soil, railway embankment, sustainability

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Authors: Najmeh Ayoqi, Emanuele Marchett

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The study of site effects is essential for seismic hazard assessment and earthquake risk mitigation. By analyzing ambient vibration data, the Horizontal-to-Vertical Spectral Ratio (HVSR) method provides valuable insights into local site characteristics, including soil properties and site resonance frequencies. In this research, the OpenSWPC has utilize algorithms to model 2D and 3D seismic waveforms in Florence, a historic region of Italy. The simulated results are compared with real seismic data recorded by urban seismic networks to assess the accuracy and reliability of the model. The HVSR peak frequency dependence on amplitude was carefully analyzed, yielding a well-defined H/V curve and fundamental frequency. The results align with the SESAME (2004) reliability standards, with peak frequencies falling within the 0.2 to 1 Hz range. These findings contribute to a more precise understanding of site response characteristics in Florence, aiding in improved seismic risk evaluation and urban planning. The result of this effort is the incorporation of numerical topography in accordance with HVSR analysis into the 3D map of Florence.

Keywords: site effect, HVSR, urban area, OpenSWPC software, seismic hazard

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Authors: Hirokazu Sasaki, Shunji Kanie

Abstract:

It is broadly known that the construction of tunnels through serpentine rock frequently encounters difficulties in keeping the construction schedule because the excavated shape of the tunnel cannot be maintained as planned due to the high expansion pressure of the serpentinite rock caused by excavation. Therefore, the tunnel lining is deformed due to large pressure, and the shoring patterns should be modified according to the properties of serpentine rock while the main excavation is undergoing. It often causes delays in the construction period and increases in the cost. For this reason, advanced borings which are the boring heading forward in advance of the main excavation are carried out, and the characteristics of the serpentinite rock are examined for their mechanical behaviors before the main excavation. However, the data obtained by the advanced borings are not fully utilized for construction management. This paper analyzes the data obtained from advanced boring at the multiple construction sites of tunnels through serpentine rock in Hokkaido, Japan. It aims to propose an appropriate construction management method to evaluate the construction period and the cost under the main excavation based on the data obtained by the advanced boring. In this study, the records of three tunnels penetrated through serpentine rocks in Hokkaido were analyzed based on 41 advanced borings. The advanced borings provide the records of boring pressure, perforated length in forward, and an abundance of serpentinite rock in the sample core, as well as their forms of existence such as lumpy, leafy, or clay-like shapes. In addition, the displacements of the excavated surfaces of the tunnels during excavation are recorded with data at the corresponding location of the advanced boring. After the excavation of the tunnel, the displacements of the inner surface of the tunnels are observed to confirm the convergence in deformation. Since the thickness of the rock cover above the tunnel is different from each other as well as the forms of existence of serpentine, there are large variations in the amount of displacement of the inner surface among these tunnels. In addition, the convergence times in the displacement are also different from each other. The authors thought that those differences could be predicted by the perforating data of the advanced boring as well as the abundance of serpentinite rock with their forms of existence. The authors conducted a statistical study to correlate the displacement of the excavated surface and the time for convergence in displacement, which are the most important factors in determining the tunnel shoring pattern. Specifically, the authors verified the relations between the perforated length of advanced borings, the clumping rate of serpentinite rock, and the amount of internal displacement of the tunnel. It is confirmed that those relationships are very helpful in deciding the required shoring pattern and useful in predicting the convergence time in displacement. This research makes it possible to evaluate the whole construction period, even under the main excavation.

Keywords: tunneling, serpentine rock, construction management, advanced boring, deformation of the tunnel, construction period, construction cost

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Authors: Ian Xavier S. Tupas, Divina R. Gonzales

Abstract:

The Philippines faces a significant housing crisis, with an estimated backlog of 6.5 million units. With this, the study employs a case study approach evaluating the potential of Cement Bamboo Frame Technology (CBFT) as a sustainable solution for affordable social housing; a comparative analysis was employed by integrating Life Cycle Assessment (LCA), Carbon Footprint Analysis (CFA), and Life Cycle Cost Analysis (LCCA) to assess the environmental and economic viability of CBFT housing against traditional Reinforced Concrete (RC) construction methods. The study’s findings underscore the potential of alternative methods in reducing environmental impact, with CBFT demonstrating a 6,445 kg CO₂e (45.94%) reduction in greenhouse gas emissions, along with significant improvements in various other impact categories compared to traditional housing. Furthermore, the total life cycle cost of CBFT housing is 29.64% lower than traditional housing, emphasizing its capability for economic advantages in resource-constrained settings. The implications of this study extend towards sustainable housing developers of the country, providing evidence-based data enhancing quality and safety to the development of low-income communities. The study offers a viable alternative pathway for addressing the country's dual challenges of sustainable and affordable housing.

Keywords: bamboo-based construction, carbon footprint analysis, life cycle assessment, life cycle cost analysis, social housing

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Authors: Karam Jaradat

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The objective of this study is to investigate the macro- and micromechanical behavior of a stone-column-reinforced slope. Slope failures, whether induced by natural processes or human activities, are often unpredictable and can occur with minimal warning, leaving limited opportunities for preventive measures. Among various reinforcement techniques, stone columns are frequently employed to enhance the stability of slopes in soft soil conditions. This study employs a coupled finite volume–discrete element method (FVM-DEM) numerical model to assess the stability of a cut slope reinforced with stone columns. The slope domain is modeled using the finite volume method with the modified Cam-Clay constitutive model, while the stone columns are represented within the discrete element domain using an elastic perfectly plastic contact model. Various stone column placement configurations are analyzed and compared to evaluate their effectiveness. The results of the coupled FVM-DEM simulation indicate that the onset of plastic flow, which leads to slope failure, is strongly correlated with the percentage loss in the contact force network among individual stone column particles. The findings presented in this study provide insights that can be leveraged to optimize slope reinforcement strategies, particularly those involving stone columns, to enhance slope stability and mitigate failure risks.

Keywords: finite-volume method, discrete element method, slope stability, multiscale

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Authors: Rizki Hidayatullah, Foreman Lois Alberto Nainggolan, Arie Arfianto

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A 24-inch gas pipeline passing through a water drainage crossing at an oil palm plantation, which has sandy clay soil, experienced erosion due to water flow. The erosion caused the soil surface to wear away, exposing approximately 20 meters of the pipeline. This resulted in a free-span pipeline suspended at an elevation of 3 meters above the ground. In addition to the exposed and free-span issues, other threats such as corrosion, flooding, and earth movement needed to be assessed in accordance with ASME B31.8S to prevent failure. A pipeline integrity program was conducted using a risk assessment approach referring to ASME B31.8S, threat identification was carried out through In-Line Inspection (ILI), and integrity assessment was performed in accordance with ASME B31G. All data related to these processes were maintained in the Asset Integrity Management System (AIMS). The risk assessment results indicated that the gas pipeline segment was at a high-risk level. To mitigate the risk, a pipe bridge was constructed to support the pipeline, allowing water to flow continuously without disturbing the pipeline. The construction of the pipe bridge successfully reduced the risk level from high to medium.

Keywords: integrity, pipeline, pipe bridge, water drainage crossing, risk assessment

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Authors: Ferkous Saci Abdelhakim, Kahlouche Ramdane

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This paper presents the results of a laboratory experimental study that explores the skid resistance of asphalt concrete mixtures made of local low-performance aggregates by partially replacing sand with olive mill waste (OMW). OMW was mixed with aggregates using a dry process by replacing sand with contents of 5%, 7%, 10% and 15%. The mechanical performances of the mixtures were evaluated using the Marshall and Duriez tests. A modified accelerated polishing machine was used as polishing equipment, and a British pendulum tester (BPT) was used to test the skid resistance of the samples. Finally, texture parameter analysis was performed using scanning electron microscopy (SEM) and MountainsMap software to assess the effect of OMW on the friction coefficient evolution. Using a new road wheel for a modified version of an accelerated polishing machine, which is normally used to determine the polished stone value of aggregates, the results showed that the addition of OMW up to 10% conferred a better skid resistance in comparison to normal asphalt concrete. The presence of olive mill waste in the mixture until 15% guarantees a gain of 22%-29% in skid resistance after polishing compared with the reference mix. Indeed, from texture parameter analysis, it was observed that there was differential wear of the lightweight aggregates (OMW) compared to the other aggregates during the polishing process, which created a new surface microtexture; that had new peaks; and led to a good level of friction compared to the mixtures without OMW. In general, it was found that OMW is a promising modifier for asphalt mixtures with both engineering and economic merits.

Keywords: skid resistance, olive mill waste, polishing resistance, accelerated polishing machine, local materials, sustainable development.

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Authors: Avirut Chinkulkijniwat, Cholticha Jeebtaku, Somja Yubonchit

Abstract:

This research conducted a series of experiments to examine electrokinetic performance on dewatering and settlement in soft clay subjected to two configurations of electrode including: 1) anode and cathode were placed at top and bottom boundaries respectively, and vice versa for the other configuration. These configurations were later labeled as 1AT and 1AB, respectively. It was found that the 1AB yielded the best result in terms of settlement (27.08 mm). It was concluded that the influence of electrophoresis and gravity played roles in the magnitude of settlement. Due to the upward moving of clay particles during settlement (influence of electrophoresis), placing an anode above a cathode would generate cracks that interfere with the drainage of water and, hence settlement. This study also confirms that soil dewatering is governed by electro-osmosis process rather than effect of temperature. The reduction of water content during the experiment affects the efficiency of electrokinetic technique, including electric current and electrical resistance. As such, this technique is suitable for any problem that requires a smaller amount of dewatering within the very short time period.

Keywords: electroosmotic, soft clay, soil water drainage, electrode configuration

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