1 Introduction
Water conservancy and hydropower projects are closely related to people's daily life. We should strengthen the research and application of construction technology of water conservancy and hydropower projects, improve the construction quality of water conservancy and hydropower projects and better serve the people. In the construction of water conservancy and hydropower projects, advanced construction technology must be adopted to ensure the construction progress and improve the construction quality. Among all construction technologies, excavation and support technology is very important, which is the basis to ensure the safety of water conservancy and hydropower projects.
2 Slope excavation method
2. 1 Slope excavation method
In the construction of water conservancy and hydropower projects, for the excavation of high-quality slopes, we should adhere to the principle of top-down excavation, strictly control the thickness of slope cutting layer in combination with the requirements of engineering construction and various standards, so as to avoid that the thickness of slope cutting layer is too large or too small, which will adversely affect the excavation quality and hinder the effective play of slope follow-up functions. In the stage of slope reduction and cutting, backhoe excavator should be used reasonably to ensure the rational use of machinery and complete the slope excavation construction more efficiently. In addition, in the process of slope excavation, scientific and reasonable construction technology must be adopted to control the construction quality, and professional technicians and construction personnel should be selected for strict construction.
2.2 Rock slope excavation method
The requirements of rock slope excavation are different from those of soil slope excavation mentioned above. In the process of construction, it is inevitable to encounter the edge layer of rock materials. Therefore, it is necessary to choose a scientific and reasonable excavation method, a scientific and reasonable blasting method according to the rock properties and hardness, adhere to the principle of top-down, continuously improve the slope excavation quality and construction efficiency, and efficiently complete the slope excavation construction of water conservancy and hydropower projects.
In the excavation of rock slope, the blasting method should be scientifically and reasonably selected to better complete the excavation construction. Specifically, the blasting point should be reasonably determined according to the distribution of rock strata and the angle and height of rock strata to improve the blasting quality. Usually, the thickness of rock stratum on the slope of water conservancy and hydropower projects is small, so it is necessary to strictly select the blasting point and control the cutting angle to avoid adversely affecting the excavation quality of the slope. In rock slope excavation, step-by-step blasting method can be used. In the concrete construction process, in order to avoid the adverse impact of a large blasting range on the slope, the step-by-step blasting method can be adopted to ensure the stability of the slope construction.
2.3 Trench excavation method
Different water conservancy and hydropower projects have different geographical location, geological environment and surrounding ecological environment. Therefore, in the specific excavation process, we should pay attention to the influence of the surrounding environment on the construction quality, comprehensively consider the actual situation of the construction area, scientifically and reasonably adjust the trench excavation method, try to shorten the construction period and improve the construction quality. In general, the trench excavation of water conservancy and hydropower projects can be divided into two types: layered blasting excavation and protective layer excavation near the foundation surface. Slotted layered blasting excavation method is suitable for slopes that will not directly affect the overall structure of water conservancy and hydropower projects. In the specific construction process, the trench excavation method must be selected strictly according to the contour characteristics of the slope, and the whole slope of the water conservancy and hydropower project should be divided into several small projects, and the slope should be excavated in layers, and the blasting point should be determined scientifically and reasonably to ensure that the construction meets the design requirements and control the construction with high efficiency and high quality.
2.4 Drilling and blasting methods
In the blasting construction of water conservancy and hydropower projects, drilling and blasting method can be used. Before construction, the actual situation of the project should be comprehensively considered to determine the drilling and blasting design scheme, improve the efficiency of slope excavation and blasting, shorten the construction progress as much as possible and reduce the construction cost. In the design of drilling and blasting, we should first go deep into the construction site, understand the construction progress, master the geological conditions of the construction area, carefully explore the site, and carry out productive blasting tests, and adjust the specific parameters of blasting through the tests. In addition, in blasting construction, millisecond blasting technology and presplitting blasting technology can be used to realize one-time excavation and molding, so as to minimize the damage to the slope rock mass.
3 common water conservancy and hydropower engineering slope excavation and support technology
3. 1 bolt technology
Bolt technology is one of the most commonly used technologies in slope support construction. The advantages of anchoring technology are small floor space, high safety and strong practicability. However, in practical application, anchoring technology also has some shortcomings, such as the need to use high-quality building materials and the need for refined management. Usually, the anchoring technology adopts manual grouting and manual construction by hand pneumatic drill. In the process of construction, the construction personnel should fully grasp the strike and dip angle of the slope rock, and adjust the drill bit diameter in time according to the actual situation of the construction site. If the drilling hole has reached the construction depth, it is necessary to remove impurities in the hole with high-pressure wind to avoid blockage.
3.2 Safety auxiliary steel mesh
In order to ensure the stability and safety of slope rock mass in water conservancy and hydropower projects and avoid collapse as much as possible, construction personnel should do a good job in safety protection during construction. In concrete construction, steel mesh should be set up in the broken area, especially in the key excavation area. Scaffolding may be used during construction. In the process of construction, 48mm steel pipe should be used, and the steel mesh can be bound manually with the specification of 8@20cm×20cm. In addition, in order to facilitate transportation, the laying area of steel mesh should be increased as much as possible, and it should be closely attached to the rock surface, and then effectively welded with the anchor head to form a whole, so as to better ensure the stability and safety of the slope.
3.3 concrete spraying
Adopting concrete spraying is beneficial to resist wind and rain erosion, prolong the service life of water conservancy and hydropower projects, and can play an isolation role, minimizing the adverse effects of external environmental factors and human factors. Therefore, in the new era, concrete spraying technology is widely used in slope excavation and support construction of water conservancy and hydropower projects.
Application of Slope Excavation and Support Technology in Water Conservancy and Hydropower Engineering
In the actual construction of water conservancy and hydropower projects, the application of slope excavation and support technology is conducive to improving the construction quality, and the scientific treatment and utilization of slopes can improve the regional security and the construction quality of water conservancy and hydropower projects. This paper will discuss in detail the practical application of slope excavation and support technology in a water conservancy and hydropower project. The actual excavation amount and supporting quantities of the slope of this water conservancy and hydropower project are relatively large, with the open excavation amount as high as 60,800 m3 and the earthwork amount of 243,600 m3. Slope protection construction requires 8,400 m3 of concrete.
In addition, there are many types of anchor bars that need to be used in actual construction. In the actual construction of this project, the construction must be carried out in strict accordance with the design drawings. According to the research and analysis, the two maximum values of slope excavation in this project are 120m, but in actual construction, the slope excavation value is140m m. In order to better carry out the construction, scientific and reasonable calculation should be carried out and the construction site should be carefully arranged. The ground workshop of this project is mainly a power plant, which can be arranged on the right side of the concrete rockfill dam. Four generators are placed on the construction site, and the capacity of hydro-generators is about 880MW. Then comprehensively consider the actual situation of the construction site and the slope situation, do not carry out blasting construction, strictly control the blasting construction process and location, and ensure the excavation quality.
For slope excavation support and blasting in excavation technology, the specific construction process is as follows: ① Prepare for blasting construction, strictly control the blasting time and location, fully ensure the amount of explosives in the construction of prefabricated holes, and closely observe the particle vibration. (2) Hydraulic drilling is adopted. During construction, drilling and drilling bit are controlled in a balanced state, and the distance is strictly controlled. (3) Strictly control the blasting standard and the diameter of prefabricated holes.
Precast holes mainly include slope precast holes and horizontal precast holes, so the size should be controlled according to the actual situation in concrete construction. Through the application research of slope excavation and support technology in this project, it is found that various construction difficulties will inevitably be encountered in the actual construction of slope excavation and support in water conservancy and hydropower projects, and these problems can be properly solved by using slope excavation and support technology scientifically and reasonably. In the concrete application of shallow support, the drainage hole in the later stage of the project is beneficial to realize long-term drainage, improve the stability of slope and avoid the danger of mountain drainage. Through the actual construction of this project, the application advantages of slope excavation and support technology are reflected, which not only effectively improves the construction quality, but also shortens the construction period as much as possible, reduces the construction cost and improves the economic and social benefits of construction enterprises.
5 conclusion
With the development of social economy, the construction of water conservancy and hydropower projects has made great progress, and people's requirements for the quality of water conservancy and hydropower projects are getting higher and higher. Therefore, the application research of slope excavation and support technology should be strengthened to ensure the smooth completion of water conservancy and hydropower projects. In the specific application process, it is necessary to conduct on-the-spot investigation on the construction site, comprehensively consider the changes of geographical environment, and select the excavation and support technology that meets the actual needs, so as to ensure the excavation quality of concrete and slope and the overall construction quality of water conservancy and hydropower projects.
The application of the above slope excavation and support technology in water conservancy and hydropower projects is the content of consultation and arrangement in Zhong Da.
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