Hasil untuk "Hydraulic engineering"

P. Swamee, A. K. Jain

Maryam Mirhashemi, Ali Shahnazari, Alireza Zarei Ghorkhodi

Extended Abstract Background: A broad understanding of the dimensions and elements of integrated management is necessary to achieve the effective management of water resources. According to the report of the Technical Committee of the Global Water Partnership, integrated management of water resources is a process that contributes to the protection, development, and coordinated exploitation of land water resources and other related resources to maximize economic and social well-being in an equitable manner without jeopardizing the stability of vital ecosystems. Achieving this goal requires providing the necessary tools to create the necessary infrastructure for the correct implementation of integrated management of water resources and achieving sustainable development goals. In this regard, the current research was conducted to identify the tools required for the integrated management of water resources to influence sustainable development. Methods: In the current descriptive-analytical research, information was collected through library studies and distribution of questionnaires. At first, the comprehensive concept of integrated management of water resources was chosen by reviewing different and varied international views and the results of world water meetings and conferences. Then, the principles, structure, challenges, and goals of integrated water resources management and the relationship with sustainable development were also examined by referring to international sources, such as World Bank reports, FAO documents and meetings, United Nations Development Program, documents related to the perspectives of the Technical Committee of the Global Water Partnership Program, documents of the United Nations Global Water Assessment Program, the United Nations 2030 document and also approved upstream documents, the water management of the country (including the macro water policies, the eighteen water policies of the country, the twenty-year vision document in the water sector, and the fourth development plan, documents and reports related to national and international conferences focusing on the integrated management of water resources and sustainable development, as well as the studies of researchers. To identify the tools needed for the integrated resource management approach to facilitate the sustainable development process, the effectiveness of four criteria, including 1) water resource protection and exploitation criteria, 2) policy making, 3) social, and 4) economic, on the implementation of the integrated water resources management approach in the Tajen catchment basin was evaluated by distributing 40 questionnaires among professors and students of the water engineering department at Sari University of Agricultural Sciences and Natural Resources. The questionnaire of the water engineering department of Sari University of Agricultural Sciences was validated after making corrections, and the final version was completed for distribution. The reliability of the questionnaire was evaluated using Cronbach's alpha coefficient. The questionnaire was compiled in such a way that there were 13 items and 5 subcategories for each component based on the Likert scale with numerical scores including very low (1), low (2), medium (3), high (4), and very high (5). The Cronbach's alpha obtained for the prepared questionnaires was equal to 0.891, which indicates the very good reliability of the prepared questionnaires. Finally, the effectiveness of each of these components in the implementation of the integrated water resources management approach was determined based on percentage by using the ratio of the total scores of each component to the number of distributed questionnaires. Results: Based on the evaluations, the component of protection and exploitation of water resources had the most effectiveness (60.64%) on the implementation of integrated management of water resources in the Tajen catchment basin. On the other hand, policy levers had the second priority (40.52%) of effectiveness, and socioeconomic sectors had the third (52.40%) and fourth (43.30%) priorities, respectively. According to the above-mentioned results, it can be realized that in the current situation and the water crisis, the protection and exploitation of water resources is one of the basic pillars of achieving integrated management of water resources and ease in achieving sustainable development in the region. On the other hand, the impact of other components cannot be ignored because the successful implementation of an integrated approach to water resources and achieving sustainable development depends on comprehensive attention to all managerial, economic, social, and environmental sectors. This is because these tools are complementary to each other and the disruption in the availability of each of them leads to limitations in achieving the goals and perspectives of sustainable development in a region. This also requires the creation of necessary infrastructure in different sectors. Conclusion: Factors such as population growth, economic development, and climate change have adversely affected the water resources of the Tajen catchment basin. Since goals such as sustainable water supply, ensuring public health, wastewater treatment, irrigation and drainage plans, and watershed protection cannot be properly implemented by taking temporary measures, the integrated management of water resources will ensure the continuous implementation of these goals. In general and according to the studies conducted in the current research, integrated management of water resources and sustainable development in the Tajen watershed and other areas are two inseparable components for the continued survival of a region. Therefore, providing the necessary infrastructure for this matter should be considered the main pillar of watershed management planning. This will not be possible except with the participation and coordination of all bodies, organizations, stakeholders, and users of water resources. The lack of a cooperative perspective is one of the biggest challenges in managing water resources and, consequently, achieving sustainable development. Therefore, the expansion of the participatory management approach in all dimensions related to water resources and achieving the goals of sustainable development can improve the current conditions and guarantee favorable future conditions to some extent.

Zhixiong Wu, Yijie Wang, Liming Hu

Foam plays a crucial role in conditioning the mechanical properties of coarse-grained soil during earth pressure balance shield tunneling. Experimental findings have shown that an appropriate foam injection ratio improves the workability and compressibility of conditioned soil, while reducing its shear strength under undrained conditions. Understanding how foam operates in soil pores is essential for interpreting these phenomena. This study utilized a theoretical two-dimensional (2D) model to analyze the effects of gas saturation, gas-liquid interface, and gas dissolution on the undrained mechanical properties of foam-conditioned soil. Based on these analyses, a constitutive equation was developed, using the transition void ratio, compression index and contact coefficient as key parameters to describe the relationships among vertical stress σv, void ratio ec, and shear strength τ. The undrained mechanical properties calculated by the 2D model align well with experimental observations, indicating that while foam enhances the bonding force between soil particles, both excessive and insufficient gas saturation, along with larger contact angles, notably undermine this enhancement, resulting in unsuitable workability. A gas saturation of 0.5–0.8 is recommended for soil conditioning. Under typical chamber pressures, the effects of gas-liquid interface and gas dissolution on compressibility and shear strength are negligible. The constitutive equation demonstrates excellent agreement with experimental data, and can well predict the variations in σv-ec-τ. This study contributes to understanding the role of foam in soil pores, and the developed constitutive equation serves as a valuable reference for describing the undrained mechanical behavior of foam-conditioned coarse-grained soil.

Pengquan Wang, Runjie Li, Shengkui Cao

To achieve sustainable development goals in Huangshui River Basin (HRB), strengthening adaptive water resources management under the dual impact of climate change (CC) and human interventions (HI) is of great significance. Multiple mathematical and statistical methods were employed to determine the runoff trend and breakpoint in HRB. The elasticity of CC and HI on the runoff decline and their contributions were quantitatively discerned based on the Budyko hypothesis, complementary method, and SWAT hydrological model. The results show that (1) the runoff showed a decreasing trend, with a runoff breakpoint in 1990; (2) the elasticity coefficients indicated a 1% increase in P, ET0, and n, leading to a 2.19% increase, a 1.19% decrease, and a 1.52% decrease in the runoff, respectively; (3) the Budyko framework determined the contribution of CC and HI to runoff decline in HRB to be 37.98–41.86% and 58.14–62.02%, respectively, and that estimated by SWAT hydrological model to be 38.72 and 61.28%, respectively; (4) HI were the primary factor for runoff decline in HRB, where direct anthropogenic disturbances such as water withdrawals and water conservancy project construction were the main drivers. The findings have important scientific significance for water resources planning and management in HRB. HIGHLIGHTS We determined the change trend and breakpoint of annual runoff from 1959 to 2014.; The runoff elasticity was estimated theoretically based on the Budyko hypothesis for 20 mountainous catchments and 5 hydrographic cross-sections in HRB.; The complementary method calculated the contribution threshold of climate change and human interventions to runoff changes.; SWAT models were used to discern runoff change attributions.;

Linchong Huang, Jianjun Ma, Ming-feng Lei et al.

Abstract This paper reports a case study on shield tunnel lining damage induced by soil-water inrush occurred in Tianjin Metro Line 1, China through both field monitoring and numerical simulation. This incident was triggered by the non-watertight boring work of thru holes adjacent to the cross passage between the twin tunnels. Under high hydraulic gradient, the seepage-prone weak zone was formed and extended, then the outburst of soil-water slurry was occurred. Measures including plugging engineering cotton, injecting quick-setting cement and welding partition plate of steel segments, had been taken but in vain. The outburst of soil-water slurry induced soil movement around the cross passage, thus leading to the damage of tunnel lining and ground surface settlement. After sealing the water ingress holes, stabilization methods including surface grouting and inside tunnel back grouting were applied. The mechanisms of segment lining damage and the effectiveness of stabilization are investigated through both numerical simulation and field monitoring data analysis. Lessons learned from this incident have been discussed, thus providing reference for potential shield tunnelling under similar engineering conditions.

Eduardo Ariel Ruiz Murillo

La protección de los recursos hídricos a través de la implementación de procesos de tratamiento de las aguas residuales que son depositadas en estos se ha convertido en un gran reto para la región centroamericana, dado que cada vez es más notoria la eutrofización de los cuerpos de agua derivado de las descargas de agua residual con significativas concentraciones de nitrógeno y fósforo. Derivado de lo anterior, se ha estado realizando diversas investigaciones para proponer mecanismos locales que permitan reducir estos nutrientes, siendo uno de ellos la utilización de la semilla de Tamarindus índica debido a que su composición química se ha encontrado ácido glutámico lo cual según Campos y colaboradores (2003) son responsables de su capacidad de coagulación. En este estudio se analizó el desarrollo de un coagulante a base de la semilla de Tamarindus índica para evaluar su capacidad de reducción de fosfato-P y nitrato-N en aguas residuales proveniente del tratamiento secundario, obteniéndose una reducción máxima de 46.42±24.06% para el fosfato-P y de 37.87±29.61% para el nitrato-N, aplicando dosis de 120 y 95 miligramos de coagulante orgánico respectivamente. Por lo anterior la semilla de Tamarindus índica puede ser una opción para reducir el fosfato y nitrato cuando se requieran reducciones menores a 50%.

Ha Thi Viet Tran, Viet Nguyen Minh, Huong Thi Lan Nguyen

The TiO2/Bi2WO6 composite was successfully synthesized by a simple one-step synthesis. Various analytical techniques such as scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, X-ray powder diffraction (XRD), diffuse reflectance spectroscopy (DRS), UV-vis spectroscopy (UV-vis) were used to determine the characteristics of the synthesized composites. The photocatalytic activity of the synthesized composite was evaluated in the degradation of the Norfloxacin (NOR) antibiotic. Under the optimal conditions, the removal rate of NOR antibiotic with the TiO2/Bi2WO6 composite was more significant than that obtained with single materials. The outstanding photocatalytic activity was ascribed to the synergistic effect between TiO2 and Bi2WO6, which decreased the recombination of e∁Eh+ pairs and enhanced the visible light absorption capacity. The investigations on radical scavengers revealed that •O2∁Eand •OH species were primarily responsible for removing the NOR antibiotic. The potential photocatalytic mechanism was also proposed.

Mingxue Meng, Xiao Pu, Siqi Li et al.

Development of rainfed maize (Zea mays L.) is sensitive to fluctuations of environmental conditions, while whether the sensitivity varies across the growth stages is still unclear. Based on a 5-year dataset collected from consecutive observations, this study examined the sensitivities of biomass and yield production of rainfed maize to root zone soil water, air temperature and shortwave radiation at four growth stages in the Sanjiang Plain of Northeastern China under sub-humid cool-temperate climates. The multiple linear regression model was employed to establish functional relations between biomass and yield production and significant explanatory variables. A Monte-Carlo simulation was used to test sensitivities of biomass and yield production to perturbation of a single significant explanatory variable or co-perturbation of multiple significant explanatory variables. Results showed that root zone soil water prevailed over air temperature and shortwave radiation in affecting rainfed maize development for the most time of the growing period. Biomass production was most sensitive to root zone soil water which had positive variance contributions of 70 – 100% at the early and late vegetative stages and a negative variance contribution of −99.4% at the early reproductive stage. Yield production was also sensitive to root zone soil water at the early reproductive stage with a 100% positive variance contribution. Biomass and yield production were most sensitive to air temperature at the late reproductive stage and the positive variance contributions of air temperature were 97.7 – 100%. Shortwave radiation negatively contributed to biomass production by −28.6% at the late vegetative stage. The findings of this study suggest that more attention could be paid to the most sensitive factor at different growth stages of rainfed maize for great biomass accumulation and high grain yield.

Jinrui Zhang, Yingnan Qi, Tong Lv et al.

The conductive potential of nano carbon black (NCB) in cement paste is restricted due to its tendency to agglomerate. To address this issue, sodium dodecyl sulfate (SDS) is proposed as a dispersant to enhance the performance of the nano carbon black-filled cement paste. Additionally, the microstructure characteristics of the nano carbon black-filled cement paste with SDS are explored systematically from the perspective of micromorphology, hydration degree and pore structure. UV–Vis spectrophotometry (UV–Vis) proves that SDS can enhance the dispersion of NCB in suspensions. Adding 0.4% SDS to the nano carbon black-filled cement paste can effectively improve the fluidity, accelerate the setting time, decrease the resistivity and increase mechanical strength. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) reveal that SDS adsorbed on the surface of NCB plays a dispersing role in cement paste. Thermogravimetry (TG) indicates that well-dispersed NCB promotes the hydration of cement clinker, accelerates the formation of calcium silicate hydrates (C–S–H) and increases the content of Ca(OH)2. N2 adsorption-desorption (NAD) verifies that the accumulated hydration products effectively increase the specific surface area and decrease the total pore volume, indicating that SDS has a positive effect on optimizing the pore structure of the nano carbon black-filled cement paste.

J. Shang, L. J. West, S. Hencher et al.

Abstract Persistence of geological discontinuities is of great importance for many rock-related applications in earth sciences, both in terms of mechanical and hydraulic properties of individual discontinuities and fractured rock masses. Although the importance of persistence has been identified by academics and practitioners over the past decades, quantification of areal persistence remains extremely difficult; in practice, trace length from finite outcrop is still often used as an approximation for persistence. This paper reviews the mechanical behaviour of individual discontinuities that are not fully persistent, and the implications of persistence on the strength and stability of rock masses. Current techniques to quantify discontinuity persistence are then examined. This review will facilitate application of the most applicable methods to measure or predict persistence in rock engineering projects, and recommended approaches for the quantification of discontinuity persistence. Furthermore, it demonstrates that further research should focus on the development of persistence quantification standards to promote our understanding of rock mass behaviours including strength, stability and permeability.

Ricardo Vinicio Abril Saltos, Esther Marianella Giler Jaramillo, Jocelyne Pamela Morales Rea et al.

Este trabajo se desarrolló en la provincia de Pastaza, su objetivo: Determinar la incidencia del uso del suelo en las características hidroedafológicas en las captaciones Apangora y Kotococha, Huagrayacu y San Jacinto. Se determinó el área de recarga, se establecieron puntos para muestreo de suelo y pruebas de infiltración, se determinaron en el suelo los contenidos de materia orgánica, carbono, humedad, densidad aparente y de raíces. Se reportaron las diferencias estadísticas para el uso de suelo con respecto a la mayoría de parámetros, donde el mosaico, reportó mayor concentración de carbono y mayor velocidad de infiltración, también hubo correlaciones entre las características de la zona de recarga y el caudal. Se concluye que el tipo de uso de suelo, influye en la velocidad de infiltración y el contenido de humedad.

S. V. Marysyk

In the conditions of progressive contamination of surface sources of water supply and inefficient wastewater treatment when using existing water treatment technologies, the research problem and the justification of the use of sorption materials for the retention of specific pollutants, in particular heavy metal ions and radionuclides, is urgent. The parameters that determine the efficiency of sorbents are indicators of their sedimentation rate. The purpose of the experiments was to determine the sedimentation rate indicators for bentonite and copper ferrocyanide, build sorbent sedimentation graphs, and establish the estimated sedimentation rate of sorbents in the sedimentation tank based on the studied data considering temperature regime. Deposition of the sorbent in settling tanks occurs with the non-stop movement of water at a low speed in the direction from the inlet to the outlet. The experiments are aimed at substantiating the efficiency and criteria of a universal facility, which is able to work equally effectively with sorbents in different aggregate states. The process of sorbent sedimentation in water is characterized by the kinetics of sorbent flakes conglomerates sedimentation. These processes are displayed in the form of deposition kinetics graphs. The experiment used powdered bentonite and a solution of copper ferrocyanide, consisting of yellow blood salt and copper sulphate in a given proportional ratio. In the course of the study the following parameters were determined: the hydraulic grain size of bentonite powdery clay, the dependence of the sedimentation rate on the temperature regime. The liquid layer was divided into layers that show changes in the amount of suspended substances depending on the depth, which made it possible to determine the dimensions of the settling tank, the height of the liquid overflow, which, in turn, made it possible to conduct simulation experiments on virtual machines with a full-scale clarifier-absorber in accordance to geometric parameters.

J. Huber, N. Fleck, M. Ashby

Yuze Wang, K. Soga, J. DeJong et al.

Microbial-Induced Carbonate Precipitation (MICP) is an innovative ground improvement technique which can enhance the strength and stiffness of soils, and can also control their hydraulic conductivity. These engineering properties of MICP-treated soils are affected by particle-scale behaviour of the precipitated carbonate, i.e. composition, amount and distribution, which are controlled by the MICP process occurring at the particle-scale. In this study, we designed and fabricated a microfluidic chip to improve our understanding of MICP at particle-scale by observing the behaviour of bacteria and CaCO3 crystals during this process. We found that bacteria became evenly distributed throughout the microfluidic chip after the injection of bacterial suspension, grew during bacterial settling, and detached during the injection of cementation solution. Bacteria aggregated during the cementation solution injection, and CaCO3 crystals formed at narrow pore throats or open pore bodies either during or after cementation solution injections.

R. Summers, R. J. Cole, R.C. Smith et al.

Zhixiang Hu, Peiguan Zhang

A novel damage identification method that utilizes the smooth orthogonal decomposition (SOD) combined with the improved beetle antennae search algorithm (BAS) presented by previous scholars is proposed. Firstly, the damage index which can track the curvature changing of mode shape identified by the SOD method is generated by an adaptive polynomial fit method. The locations of structure damages are determined according to the damage index. Thus, the number of possible damaged elements needed to be taken into account can be reduced when calculating the degree of damage. Then, the reduction in the stiffness at the damage location of the structure is calculated by the improved BAS in which the fitness function is constructed by calculated frequencies of the damaged structure in each iteration and the modal frequencies obtained by SOD. The BAS algorithm is improved through a fusion strategy of simulated annealing theory. Thus, the improved BAS algorithm is efficient and adaptive. The effect of this combined application in damage identification has been verified by numerical examples of a simply supported beam with single damage and a cantilever beam with double damage. The numerical results show that this combined algorithm exhibits high reliability in damage identification of beam-like structures.

A. Arthington

Lena Hommes, R. Boelens

A. Amadi, A. Okeiyi

A laboratory study was undertaken to evaluate and compare the stabilization effectiveness of different percentages (0, 2.5, 5, 7.5, 10%) of quick and hydrated lime when applied separately to locally available lateritic soil, a major soil group in the tropical and sub tropical regions. Performance evaluation experiments included: Atterberg limits, compaction, unconfined compression tests, California bearing ratio (CBR), swelling potential using CBR instrument and hydraulic conductivity. The soil mixtures used for unconfined compressive strength (UCS), CBR, swelling potential and hydraulic conductivity tests were compacted at optimum moisture content using the British standard light compactive effort and cured for 28 days. It was found that the quicklime caused the soil to have lower plasticity while hydrated lime yielded higher dry unit weight. Also, higher UCS especially at higher dosages (7.5 and 10%) was produced when soil sample was treated with quicklime. Similarly, the CBR values for quicklime sample clearly indicate that quicklime-stabilized soil have superior load bearing capacity. Finally, quicklime treated specimens reached slightly lower swelling values than the hydrated lime while no appreciable distinction in hydraulic conductivity values of specimens treated with the two types of lime was observed. From the foregoing results, quicklime is adjudged to have exhibited somewhat superior engineering properties and therefore creates a more effective stabilization alternative for the soil.

G. Oliveto, W. Hager