Decades of engineering practice have substantiated that the implementation of construction joints is a pivotal method for mitigating dam cracking. The integration of various joint types, notably transverse and induced joints, within roller-compacted concrete (RCC) arch dams has emerged as a promising strategy to curtail cracking and structural failure. This approach leverages the unique structural characteristics inherent to each joint type. Given the intricate, variable, and dynamic nature of thermal stress in RCC arch dams, the design process for crack prevention, particularly the configuration of induced joints, demands an accurate representation of the dam's operational conditions from construction through to service. Investigations in practical engineering contexts have revealed that the utilization of a contact unit simulation methodology, featuring an open/close iterative function for modeling the behavior of induced and transverse joints in RCC arch dams, proves effective. This method is complemented by the adoption of equivalent strength theory as the criterion for structural integrity assessment. A comprehensive process simulation encompassing the entire dam structure further enhances the efficacy of this approach. Such simulations facilitate a more granular examination of joint placement within the dam and the structural design of the joints themselves. As a result, induced joints can be optimally opened in alignment with design expectations, thereby alleviating tensile stress triggered by temperature reductions. This strategy assures superior construction quality of the dam's concrete body, contributing significantly to the longevity and safety of RCC arch dams.
High-grade highways are an important part of the modern comprehensive transportation system. However, due to frequent natural disasters, harsh meteorological conditions, and fragile geological environments, high-grade highway construction projects face significant risks, and how to specifically manage and control these construction risks to reduce them to a socially acceptable level has become a pressing technical issue. Therefore, this study combines the construction characteristics and risk features of high-grade highways, applies the Hall's three-dimensional structural theory to comprehensively identify potential risk factors from the dimensions of time, structure, and logic, and builds the logical dimension from four aspects: people, materials, environment, and management. To filter the main influencing factors, the Delphi method is adopted to construct a risk assessment indicator system, with the expert opinions fully taken into consideration. To address the subjectivity in the weight calculation process of risk assessment indicators, the Analytic Hierarchy Process (AHP) and Entropy Weight Method are used to calculate the subjective and objective weights, respectively. A combined weighting model is established based on game theory principles and is used to optimize the weights of the risk assessment indicators. In view of the fuzziness of risks during high-grade highway construction, fuzzy mathematics theory is introduced to construct the risk assessment model. In this study, this method is applied to the construction of the Elsiyah Highway to clarify the risk level of the project and propose targeted control measures. The results show that the risk level of the Elsiyah Highway project is relatively high. The risk level is conditionally acceptable, but measures must be taken to reduce the risks.
In response to the escalating pressures of urbanization and population growth on the ecosystems and flood risks in Bor County, Jonglei State, South Sudan, this study proposes the implementation of Sustainable Urban Drainage Systems (SUDS) as a resilience-building measure. Through the design of open drainage channels featuring non-uniform flow, inclusive of main and sub-channels alongside infiltration wells, the research aims at mitigating flooding, enhancing water quality, and fostering sustainable development within the region. The necessity for managing substantial runoff volumes has been identified, with a decade of rainfall data employed to accommodate annual variability. The evaluation of SUDS techniques to mitigate flooding entails a customized design approach, integrating cost estimation with flood mitigation strategies and the assessment of short- and long-term co-benefits. Hydrological analysis of ten years of rainfall data facilitated the sizing of channels for storm events ranging from 2 to 5 years, with precipitation intensities between 73.82 and 93.08 mm/day, resulting in the planning of open trapezoidal channels with dimensions to support 5 $m^3/s$ flows. Moreover, infiltration wells, with diameters of 2–3 meters and depths of 3-5 meters, have demonstrated potential in reducing runoff volumes by up to 70% in a 0.5-hectare modelled area. The incorporation of drop structures aims to control slopes ranging from 6-15% in channels, thereby preventing erosion for flows up to 20 $m^3/s$. The adaptability of SUDS approaches, commonly applied in developed nations, to the tropical environment of Bor is scrutinized, highlighting the necessity for localized adaptation due to data limitations and modelling simplifications. The potential barriers posed by capital costs underscore the importance of a life cycle analysis. The success of SUDS implementation in Bor County is contingent upon community engagement, ensuring acceptance and ownership. It is recommended that low-cost, simplistic pilot projects, focusing initially on rain gardens and permeable pavements, precede large-scale implementation. Through strategic planning, SUDS hold the potential to enhance climate resilience in the expanding community of Bor County. An integrated technical analysis provides actionable solutions for flood mitigation, advocating for further monitoring and community-driven initiatives to transition SUDS from concept to reality.
The construction, maintenance, and repair of civil infrastructure demand substantial economic investment, underscoring the necessity of structural health monitoring (SHM) to mitigate property loss resulting from structural failures. Within the domain of SHM systems, the integration of fiber-optic sensors (FOS) is distinguished by their diminutive size, lightweight nature, resistance to corrosion, and straightforward installation procedures, thus garnering widespread recognition. Despite the voluminous publications addressing this subject, comprehensive surveys employing bibliometric and scientometric methodologies remain scarce. This review scrutinizes 1066 publications spanning the past decade through scientometric examination, delineating publication trends, journals of significant contribution, leading researchers, foremost affiliations, and the prevalence of keywords. The analysis reveals a consistent upward trajectory in research activity, with the United States and China emerging as pivotal contributors. Employing VOS viewer for clustering visualization, the study categorizes keywords into discrete clusters, elucidating the breadth of applications and the interconnectedness of topics based on the strength of their associations. This investigation stands as a novel contribution, furnishing a holistic overview of FOS research within SHM, charting historical and current trends, and pinpointing emergent research avenues. The findings are poised to serve as an invaluable repository for scholars endeavoring to incorporate SHM systems equipped with FOS into their forthcoming investigations.
Pile foundations, as one of the main foundation forms for bridges and offshore wind power structures, are prone to scour pits around them under the long-term action of water flow, leading to a decrease in bearing capacity. Traditional pile foundation scour prevention measures, such as the construction of protective jetties and riprap protection, are cumbersome and ineffective. Considering the inevitable generation of a large amount of spoil in engineering construction, by optimizing the performance of cement-stabilized soil, it is expected to use the discarded spoil for pile foundation scour management. Aiming at the underwater anti-dispersive cement-stabilized soil based on kaolin, 67 sets of single-factor rotation experiments were carried out to study the effects of changes in the addition of anti-dispersive agents ethylene-vinyl acetate copolymer (EVA), hydroxypropyl methylcellulose (HPMC) from 0‰ to 1‰, cement content from 8% to 14%, and water content from 1.4 to 2 times the liquid limit on the anti-dispersion performance, fluidity, and 7d and 28d unconfined compressive strength of the cement soil. The results show that the anti-dispersive agent HPMC can maximize the anti-dispersion performance of the cement soil, with the addition increased from 0‰ to 1‰, the anti-dispersion performance of the cement soil increased by 76.1%, but the fluidity decreased by 54.0%, and the strength of the 28d age cement soil increased by about 52.9%. Anti-dispersive agents can be added to quickly improve the anti-dispersion performance of the cement soil in pile foundation scour management, but attention should also be paid to its weakening effect on the fluidity of the cement soil; the increase in water content has the greatest impact on the fluidity of the cement soil, with the water content increased from 1.4 times the liquid limit to twice the liquid limit, the fluidity increased by 80.3%; the cement content increased from 8% to 14%, the unconfined compressive strength of the cement soil increased by more than double, and the anti-dispersion performance increased by 26.8%. Based on the experimental results, the recommended mix ratio of kaolin-based cement soil for pile foundation scour repair is: 0.75‰ EVA addition, 1.6 times the liquid limit water content, 10% cement content.
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