In opening up the mine roadway construction process, the use of shotcrete support, which is supporting the initiative to support the method, it is through the anchor bolt into the rock, and to change the surrounding rock stress state itself, the surrounding roadway form a whole and stable rock band, so as to achieve the purpose of maintaining roadway safety. However, using only shotcrete support can not prevent the surrounding rock weathering, can not prevent cracks between the rocks and the anchor bolt flaking. Therefore, bolting usually metal mesh, shotcrete combination. Shotcrete is a high strength, strong bond, impermeability good support ways. At present, widely used in concrete construction of jet dry spray and wave spray, the construction process are the following shortcomings:
1, the existing shotcrete process is on-site mixing, resulting in job site dust pollution affecting mine production safety, easy to make workers suffer from pneumoconiosis, great harm;
2, occupying valuable space underground large, is not conducive to the effective expansion of the underground construction site; spraying operation takes more workers, mine operators to increase production to bring some security risks;
3, spraying material cohesiveness poor landing rebound as much as expected 30∽50%, seriously affecting the quality of shotcrete;
4, spray material features a single, not waterproof, flexibility, softness properties; 5, roadway life is short, highly vulnerable to changes in rock stress and deformation, resulting in secondary leakage and destruction;
6, spraying machine seals too bad, too much dust when mixing;
7, when the mixing ratio of shotcrete material is not easy to grasp, the larger workers to operate randomness affect material properties play.
All these negative factors make the health of workers has been no small harm, now with enhanced awareness of environmental protection. And the shotcrete quality requirements increase, more and more of the wet concrete jet put into use in the underground.
With the development of coal mines, increasing the degree of mechanization, the use of mechanical equipment, superior performance, continue to reduce labor intensity. According to statistics, China's investment in various sectors of the rotor using concrete jet nearly one hundred thousand units, an annual update of thousands of units, use a large amount, it is our job shotcrete key equipment, its principles and structure of the work is: have Liner to a certain speed of rotation of the rotor, the surface combined with the pressure in the liner plate is fixed, combined with the board is connected to the inlet and outlet pipes Discharge elbow, when the rotor is equipped with various materials, the cup is rotated to the inlet pipe and outlet elbow connected when under the influence of gas pressure,Material through the material conveying pipe elbows and transported to the nozzle, and add water at the nozzle ejected.
In this process, the binding plate Seal and liner played a role in the composition of the gas pressure and seal materials. The main advantage of the dry concrete jet was conveying distanceLong, simple equipment, and durable. But because it is so dry concrete mixing nozzle outside mixed with water, and therefore the construction dust and rebound are Larger operations generate dust, dry spray harm the health of workers, especially in the narrow roadway construction, the dust pollution is more serious.So wet shotcrete machine is widely used.