Repair Of Hydraulic Structures Research Articles

The History Of The Irrigation System In Uzbekistan

The article analyzes on the basis of primary sources, scientific literature, Internet materials and statistical data the issues of significant attention to modernizing the irrigation system of Uzbekistan over the years of independence, providing the industry with modern equipment, protecting water resources, reclamation of irrigated lands, reconstruction, repair of hydraulic structures and increasing year to year capital investment. The research also highlights the important reforms and a number of measures taken in the water management system after the independence of Uzbekistan, as in all areas

Research on the dynamic positioning of remotely operated vehicles applied to underwater inspection and repair of hydraulic structures

Hydraulic structures (such as dams and aqueducts) can suffer from damages, such as cracks and collapse due to natural aging as well as the impact of natural disasters (such as earthquakes and floods). Determining underwater damage is generally not easy because of significant concealment and safety hazards. Remotely operated vehicles (ROVs) have gradually become capable assistants for the regular underwater maintenance of hydraulic structures. With disturbances from undercurrents and propeller reactions, achieving precise positioning of ROVs has always been a complicated technical problem, and it is also one of the important factors affecting underwater inspections and repair accuracy. To address the environmental disturbances during ROV dynamic positioning, a fuzzy predictive control algorithm combining fuzzy control and model predictive control is proposed in this paper. This algorithm can dynamically adjust the power output of propellers in real-time according to the undercurrent data measured by sensors and carry out differential correction until the ROV reaches the predetermined position. Moreover, the aim of this paper is to analyze disturbances in the longitudinal (X), lateral (Y), and depth (Z) directions during the motion of the ROV. The parameters are adjusted through the algorithm to simulate the dynamic positioning of the ROV's spatial movements. By setting different external environmental conditions, the power adjustment strategy and different dynamic positioning performances of ROVs can be obtained to enhance the adaptability of ROVs in complex environments and their stability in underwater inspection and repair and improve their underwater operation quality and efficiency.

Evaluating the Long-Term Durability of Lime Treatment in Hydraulic Structures: Case Study on the Friant-Kern Canal

The slopes along the Friant-Kern Canal were last treated in the 1970s with 4% quick lime to mitigate issues related to slope failure caused by expansive Porterville soils. The immediate benefits of lime treatment were well documented by the Bureau of Reclamation. However, questions remain over the long-term durability of lime-treated materials. In this study, we compare the engineering properties and changes in the soil mineralogy of treated and untreated sections to establish the effectiveness of lime after more than 40 years of performance. A geochemical model was developed using the GEM-Selektor program to simulate the geochemical reactions in the soil-lime system and predict stable pozzolanic products. The experimental results show a reduction in the plasticity index from 23 to 6 after lime treatment together with a tenfold increase in strength. Lime addition lowers the risk of volumetric expansion and erosion in soils from moderately high to very low. Further, a pH increase from 6.30 to 8.90 in lime-treated sections indicates that lime treatment continues to be effective. X-ray fluorescence analysis shows the presence of Ca2+ ions in quantities similar to the initial treatment dosage indicating negligible leaching of lime. The geochemical model provides evidence of the formation of pozzolanic products in the soil-lime system which was validated using thermogravimetry analysis. The performance history of the Friant-Kern Canal together with the findings of this study affirm the long-term durability of lime treatment on this project and strengthens the case for using lime in the repair of hydraulic structures.

FROM THE HISTORY OF TRANSFORMATION PROCESSES OF IRRIGATION SYSTEM IN THE FERGHANA VALLEY DURING INDEPENDENT PERIOD

The article analyzes the history of transformation processes in the water management system of the Ferghana Valley during the years of independence, the provision of modern equipment and facilities, protection of water resources, reclamation of irrigated lands, reconstruction, repair of hydraulic structures and increasing capital investment made as well. KEY WORDS: Ferghana Valley, irrigation, water shortage, land reclamation, modernization, transformation, credit, irrigation canal, reconstruction, hydraulic structures.

Innovative Solutions for the Construction and the Repair of Hydraulic Structures

Abstract Hydraulic structures underlie extraordinary conditions due to their prominent function and exposure. Thus, high demands have to be made both on construction and maintenance or repair of the structures, respectively. In order to fulfill these demands new and special technologies have to be developed that ensure an effective construction and guarantee to meet the planned service life of the building required by the owner. Against this background two innovative methods for both construction and repair of hydraulic concrete structures are presented in the present paper. The methods are based on modern concrete technology and enable to either build concrete dams in flowing water or perform concrete repair below the water level. Both methods were developed at the Institute of Concrete Structures and Building Materials at the Karlsruhe Institute of Technology (KIT), Germany and were applied in practice for construction of the Bribin underground hydropower plant in Indonesia and for repair of the river hydropower plant of Albbruck-Dogern in Germany.

Effectiveness of repairing old reinforced-concrete walls of the No. 8 lock of the Moscow Canal by prestressed anchors

1. The special works performed on overhauling by the active anchoring method (with prestressed anchors) for strengthening the walls of the No. 8 lock of the Moscow Canal with strongly expressed signs of aging after 60 years of its intense operation increased the reliability of the walls and thereby increased the service life of the lock as a whole. In this case no interference to the passage of ships was created. 2. This method made it possible not only to stop the process of irreversible movements of the top of the walls toward the chambers but also provided deflection of the walls to the opposite side. The goal of the top-priority measures to strengthen the walls was thereby achieved, making it possible to proceed to measures of the second phase — repair of the front faces. 3. Compared with the passive anchoring method, prestressed anchors immediately enter into work, the uncertainty of the degree of remaining life after strengthening walls by them decreases, the anchors are more durable due to the anticorrosion sheath, and they provide quality control of the works by testing the strength of each anchor one by one, since the testing process is an element of the technology (“self-checking” technology). 4. The method is recommended for strengthening hydraulic structures in which cracks are opening and sustained movements of separated parts are observed. It is effective at different stages of development of destructive phenomena; it is useful as a prophylactic means of increasing reliability, strength, and stability. 5. The method is economical because the service life of the repaired structure is prolonged and it requires less metal than passive anchoring with comparatively smaller hole diameters. 6. The following promoted the successful use of the method when repairing the lock walls: high degree of development of the technology created by Gidroproekt and checked by it in new construction on the Hoa-binh, Sayano-Shushenskoe, and Rogun hydrostations; its correspondence to international rules established by the International Federation on Prestressed Reinforced Concrete; the specialized character of the construction organization (the Geotekhnika firm) that carried out these works with a high quality on the No. 8 lock with improvement of the technology and the quality control. 7. The method has ceased to be new. Its rather wide use during the past 10 years placed it in the ranks of the usual special works and well-mastered and reliable engineering means in construction. It is useful both in new construction and in reconstruction and repair of hydraulic structures as well as in other areas of construction.

Substantiating the method of underwater asphalt linings for the repair of hydraulic structures

1. Analytical and graphical relationships between the number of pipes, their diameter, the flow of asphaltic material that can be passed through them and their depth of the immersion were derived on the basis of theoretical and experimental studies on the technology of the underwater placement of an asphalt lining in repairing hydraulic structures. 2. The temperature-energy regime of the system encountered in placing an underwater asphaltic lining, which permits proper designation of pipe diameter as a function of the temperature of the asphaltic material and the water surrounding the delivery pipes, is studied. 3. For lining under water, it is recommended that an asphalt mastic or solutions be employed as the most transportable materials, which make it possible to (fill all available recesses and which do not delaminate during transportation and lining.

Repair of hydraulic structures with sprayed concrete

1. The restoration of concrete surfaces with sprayed concrete is an efficient, highly mechanized, and comparatively economical method; and the work is of high quality. 2. The described method may be expeditiously employed in repairing surfaces while operating the structures; for example, in repairing lock chamber walls while operating the locks. 3. When it is possible to lower the water level in canals, sprayed concrete may be recommended as the most expedient method of placing a monolithic cover on stone paving or on a gravel base course; and also for resurfacing the protective slope covering. 4. Locating the equipment and materials on a self-propelled ship provides the greatest convenience and mobility for working on existing structures.