| The long-term deformation and floor heave are the difficulties in the support for mine soft rock roadway. Based on New Orleans supporting theory, full section bolting with mesh technology is adopted in soft rock roadway in order to effectively control its long-term deformation and floor heave. Soft rock roadway roof bolting supporting construction has been well established, but soft rock roadway floor bolting supporting construction has been a problem that the existing floor roof bolter is difficult to meet the requirements of soft rock roadway floor bolting supporting construction. The reason is that the domestic and foreign research on drilling hole with small diameter in soft rock roadway is little, and there are no mature and available design theory and method of roof bolter for floor of soft rock roadway.Aiming at the problem of mine soft rock roadway floor bolting supporting construction, research on mechanism of small diameter drilling for the soft rock roadway floor, spiral drilling characteristics and design of roof bolter was carried out in this paper. Based on mechanism of spiral drilling slagging and design research of drilling parameters design theory, design theory and method of roof bolter for soft rock roadway were proposed. Then, roof bolter and simulation test device for soft rock roadway bolting construction were made, and related research was carried out. Research contents in this paper are as follows:Properties of soft rock were analyzed, rock breaking theory of small diameter drill for soft rock roadway and mechanism of small diameter spiral drill slagging were studied and then, rock breaking characteristic parameters of drill and spiral drilling slagging parameters of drill pipe were analyzed, and calculation method was obtained, and design theory and method of roof bolter for soft rock roadway were proposed.Based on design theory and method of roof bolter proposed, optimal design calculation of spiral drilling parameters of hydraulic roof bolter for soft rock roadway were conducted. Based on the actual condition of the underground coal mine, drill power adopted full hydraulic pressure, walking adopted the crawler-type walking mechanism, and drilling propulsion type adopted cylinder- chain type doubling propulsion mechanism. Based on the performance requirements, hydraulic system was designed, and all the hydraulic components were optimized.Mechanical analysis and modal analysis of drill frame were made with ANSYS software and the drill frame was optimal designed with Design Explorer optimization module, static mechanical analysis of drill frame stiffness and strength were made. Then vibration of drill frame was analyzed in the process of drilling and drill frame was optimal designed. Drill frame was designed with the stiffness strength meeting the requirements, which has compact structure, small size, and light weight.Dynamic characteristic simulation analysis was carried out on the hydraulic system of roof bolter by AMESim software. Based on the hydraulic system has been designed and roof bolter parameters designed, simulation parameters were set to ensure the consistent with developed prototype. The loop, walk and drilling circuit simulation analysis show that the choice of hydraulic components can be well matched and the designed hydraulic system can satisfy the requirement.A hydraulic roof bolter for soft rock roadway and simulation test bed were developed, and simulation drilling test and drilling test underground were carried out, and the test data was analyzed. Test data obtained in simulation drilling test was analyzed to get relationship between spiral drilling parameters and the drilling speed, then fitting curve and formula of spiral drilling parameters and the drilling speed were obtained by Microcal Origin software. Drilling test underground focused on the assessment of its spiral parameters, evaluating the performance parameters. Data in simulation drilling test and drilling test underground shows that design theory and method of roof bolter for soft rock roadway are correct, and the design parameters of the roof bolter is reasonable, fully able to meet the coal mine soft rock roadway drilling requirements.Innovative research results this paper has made are as follows:1. based on theoretical analysis and experimental study, the drilling mechanism for soft rock roadway and relationship characteristics of drilling parameters are found:1) The difference between spiral drilling characteristics in soft rock roadway and others is that there is almost no grinding zone, transition zone and repeated crushing area in relationship graph between propulsion and drilling speed2) Drilling speed increases with propulsion and speed increase, there is an optimal value; torque increases with drilling depth and gradually tends to a stabilized value;3) The preliminary results were obtained that under the same propulsion, the larger the diameter of spiral drill pipe, the larger the drilling speed, and under the same drilling speed, large diameter of spiral drill required greater speed, and under the same drilling depth, drilling deep of the two spiral drill pipe changes little with drilling torque but torque consumption of large diameter of spiral drill is slightly larger;4) The degree of wet' impact on the drilling slagging as follows: moisture more than 5% begins to affect the slagging; over 8% raise serious slag; over 10% not able to slagging.2. Based on the research on rock breaking theory of small diameter drill for soft rock roadway and mechanism of small diameter spiral drill slagging, combined with the research on other parameters of roof bolter by ANSYS software and AMESim software, design theory and method of roof bolter for soft rock roadway were proposed. Based on the design theory and method, a hydraulic roof bolter for soft rock roadway was developed for the first time at home. The prototype was developed, and the test was conducted underground, getting a better test result.This paper not only provides theoretical basis for design of hydraulic roof bolter for soft rock roadway, but also provides efficient roof bolter for soft rock roadway bolting construction, promoting the technology advance and equipment innovation for soft rock roadway bolting supporting. |
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