At present, in the construction of mine roadways, railway and highway tunnels, water conservancy culverts, underground projects, high-rise building foundation pits, military projects, etc., the internationally advanced support method, concrete (concrete), is widely used. The wet shotcrete machine is the main equipment for this operation. In order to solve the three major problems of dry spraying machine or wet shotcrete machine for spraying concrete, the use of wet spraying machine is very important.
Overview of the development of related products and technologies at home and abroad" Since the 1960s, western developed countries have begun to implement wet spraying technology, and various wet spraying machines have been developed one after another. At present, in some western countries, wet shotcrete machines have gradually become concrete spraying operations. Many countries have reached more than 80% of the main machinery and tools, and dry spraying machines and tide spraying machines are being phased out.
In China, for various reasons, dry spraying machines are still the main spraying equipment. However, with the increase of people's awareness of environmental protection and the improvement of the quality of shotcrete, more and more wet concrete spraying machines have been put into use. In some large-scale water conservancy projects bidding internationally, such as the Ertan Hydropower Station, the Xiaolangdi Project on the Yellow River, and the Three Gorges Project, wet concrete spraying is used. The various wet concrete spraying machines currently used in China are mostly equipment imported from abroad. In recent years. Some domestic units have also begun to develop several types of wet concrete spraying machines. For example, the JHPS6IH concrete spraying machine developed by Henan Coal Research Institute Co., Ltd. (won the bidding of large-scale engineering and coal group projects for many times, and has been well received in the industry), KBS-8A full hydraulic pumping concrete wet spraying machine . The main advantages of this type of wet concrete spraying machine are:
(1) The dust concentration near the machine and outside the nozzle is greatly reduced, and the harm to the health of workers is eliminated.
(2) Low resilience. When dry spraying, the concrete rebound can reach 15%-50%. Using wet spray technology. The rebound rate can be reduced to less than 10%.
(3) During wet spraying, because the water-cement ratio is easy to control and the concrete is not degraded, it can greatly improve the mouth quality of sprayed concrete and improve the homogeneity of concrete. When dry spraying, the water-cement ratio of concrete is determined by spraying. The hand is adjusted based on experience and visual inspection. The quality of concrete depends to a large extent on the correct operation of the robot.
