At present, in the construction of various mine roadways, railways and highway tunnels, water conservancy culverts, local engineering, high-rise building foundation pits, military engineering, etc., the international advanced support method of spray anchor support is widely used. Concrete. The jet is the main equipment for this job. In order to solve the three problems of large dust, rebound, and poor quality of dry spray or tidal jet sneeze, it is very important to use a wet spray machine.
Overview of related products and technologies at home and abroad "Since the 1960s, western developed countries began to implement wet spray technology, and various wet jets were developed. Currently, in some western countries, wet concrete jets have gradually become sneezing operations. The main machines have reached more than 80% in many countries, and dry spray machines and tide spray machines are gradually being phased out.
Domestically, due to various reasons, dry sprayers are still the main injection equipment. However, as people's environmental awareness has increased and the quality requirements for shotcrete have increased, more and more wet concrete jets have entered use. In some large-scale water conservancy projects that are internationally tendered, such as Ertan Hydropower Station, Yellow River Xiaolangdi Project, and Three Gorges Project, wet concrete spraying operations are used. The various wet concrete sprayers currently used in China are mostly imported from abroad. In recent years. Some domestic units have also begun to develop several wet concrete jets. For example, the JHPS6IH concrete jet machine developed by Henan Coal Science Research Institute Co., Ltd. (multiple bids in large-scale engineering and coal group bidding projects, has been praised in the industry), KBS-8A full hydraulic pumping concrete wet spray machine. The main advantages of this type of wet concrete jet are:
(1) The dust concentration outside the machine and outside the nozzle is greatly reduced, and the harm to workers' health is eliminated.
(2) Low rebound. When dry sprayed, the concrete rebound can reach 15%-50%. Wet spray technology. The rebound rate can be reduced to less than 10%.
(3) When wet spraying, because the water-cement ratio is easy to control and the degree of concrete is not high, the quality of the shotcrete can be greatly improved and the homogeneity of the concrete can be improved. When dry-spraying, the water-cement ratio of the concrete is sprayed. The hand is adjusted according to experience and visual inspection. The quality of the concrete depends to a large extent on the correct operation of the operator.