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.

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.

In response to the mechanical performance alterations of PVC-P geomembranes due to improper handling or subgrade particle action during construction and operation, a series of axial tensile tests on PVC-P geomembranes with various scratch damages were conducted. Multifactorial variance analysis was performed using Python, and a multivariate regression model for the fracture strength and elongation at break of scratched PVC-P geomembranes was developed using SPSS. The precision of the regression model was evaluated using parameters such as the coefficient of determination (R²), mean absolute error (MAE), mean absolute percentage error (MAPE), and root mean square error (RMSE). The results indicated that the fracture strength and elongation at break of PVC-P geomembranes are significantly affected by a combination of scratch angle, length, and depth. The impact on elongation at break is greater than on fracture strength, with the scratch angle having the most significant effect. The developed multivariate regression model yielded R² values of 0.98 and 0.97 for fracture strength and elongation at break, respectively. The MAEs were 0.62 kN/m and 7.96%, and the MAPEs were 3.06% and 5.13%, respectively. The RMSEs were 0.84 kN/m and 12.08%. The high fitting accuracy of the model suggests its utility for evaluating the mechanical performance of PVC-P geomembranes with scratch damage.

This study introduces a novel methodology for optimizing the design of small dams in the Western Desert of Iraq, a region characterized by its vast expanse and significant flood water influx, particularly in the Horan Valley. The approach integrates Geographic Information Systems (GIS) with a custom-developed Visual Basic program, termed the Optimal Height and Location Model (OHALM), to determine the most effective dam height and location. The initial phase of the study involved utilizing GIS to identify potential dam sites in Horan Valley, based on a set of defined criteria. Subsequently, OHALM was employed to ascertain the optimal dam height, taking into account economic factors such as minimal evaporation losses and maximal water storage capacity. The study culminated in the selection of 13 proposed small dam sites, with height estimations ranging between 12.5 to 14 meters, allowing for a total water storage capacity of approximately 303 million cubic meters. This capacity expansion resulted in an increase of the valley's water body area from 15 square kilometers to 90 square kilometers. Comparative analysis of these proposed dam heights with those of existing structures in the valley revealed a relative variance of 10.4% in the upstream, 7.2% in the midstream, and a comparable percentage in the downstream areas. The research highlights the efficacy of integrating GIS and Visual Basic programming for the strategic development of water resource management systems, particularly in arid regions. This innovative approach demonstrates the potential for significant improvements in water storage and management, addressing the critical need for sustainable water resources in arid environments.

In the realm of civil engineering and industrial construction, the infusion of waste materials into road pavements has emerged as a pivotal strategy for augmenting the attributes of asphalt mixtures while concurrently mitigating the environmental repercussions associated with waste. This investigation delineates a dry method for the preliminary treatment of waste paper, preceding its amalgamation into asphalt mixtures. The focal point is the incorporation of waste paper and Cement Kiln Dust (CKD) as modifiers in Stone Mastic Asphalt (SMA). It is posited that the inclusion of waste paper fibers can substantially elevate the SMA's flexibility and crack resistance. Simultaneously, CKD is purported to bolster the asphalt's strength and durability through its cementitious characteristics. A series of SMA blends were formulated, integrating waste paper and CKD in varied proportions ranging from 0.2% to 1% by weight. Subsequent evaluations encompassed analyses of air voids, density, drain-down characteristics, Indirect Tensile Strength (ITS), and Marshall Stability. The outcomes revealed that the drain-down test exhibited enhancements in volumetric parameters, notably density and air voids. Concomitantly, there was a 33% increase in Marshall Stability and a 37% improvement in ITS. Additional advancements were observed in Marshall Flow, Tensile Strength Ratio (TSR), and skid resistance. In summation, this study establishes that waste paper, when appropriately treated and amalgamated with CKD, can be efficaciously utilized in SMA mixes, yielding mixtures with superior volumetric and mechanical properties. This methodology not only augments the stiffness and minimizes binder drainage but also enhances rutting resistance. Most crucially, it paves the way for sustainable and ethical practices in the reuse and recycling of waste materials.

In regions characterized by extreme cold and elevated altitudes, notably in the northwest, the mechanical characteristics of construction materials such as Ultra-High Performance Concrete (UHPC) are critically impacted by ambient temperatures. This study investigates the mechanical properties of UHPC subjected to low-temperature curing environments, conducting uni-axial compressive and splitting tensile strength tests on UHPC specimens, which comprise water, dry mix, and steel fibers. These specimens were cured at varied temperatures (-10℃, -5℃, 5℃, 10℃). Utilizing damage theory principles, the loss rate in compressive strength of UHPC post-curing was quantified as a damage indicator, revealing internal degradation. A predictive model for damage under low-temperature maintenance was developed, grounded in the two-parameter Weibull probability distribution and empirical damage models. Parameter estimation for this model was achieved through the least squares method, informed by experimental data. The findings indicate a rapid increase in UHPC’s mechanical strength at all curing temperatures, with 7-day strength achieving approximately 90% of its 28-day counterpart. A positive correlation was observed between the mechanical strength of UHPC, curing temperature, and age. Despite a reduction in mechanical strength due to low-temperature curing, UHPC was found to attain anticipated strength levels suitable for construction in cold environments. The proposed model for predicting UHPC damage under low-temperature conditions demonstrated efficacy in estimating the strength loss rate, thereby offering substantial technical support for UHPC’s application in northwest regions.