During the pore-forming stage of floor heave treatment, the phenomenon of gravel sediment accumulation in the bottom hole often occurs, which causes great difficulties in the normal installation of ...the anchor cable. Based on this observation, a new anchor cable installation method was proposed, which involves installing a drill bit at the front end of the anchor cable to assist its drilling. With the help of an anchor cable drilling test bench, the influence of the bit, motion parameters, and hole environment on the performance of anchor cable drilling was studied. Through the co-simulation of the discrete element method (i.e., multibody dynamics (DEM-MBD)), the drilling process of the bit anchor cable was simulated, and the dynamic characteristics of the bit anchor cable drilling in the bottom hole gravel sediment were analysed. The results show that installing a drill bit in front of the anchor cable can greatly reduce the drilling resistance and hamper torque during anchor cable drilling. When the rotational direction of the bit anchor cable is consistent with the spiral direction of the anchor cable, the bit anchor cable can exhibit better drilling performance. The drilling resistance and hindering torque of the bit anchor cable are the largest when drilling in soaked particles, followed by drilling in dry particles, and the smallest occurs when drilling in moist particles. The research results can provide reference for the parameter setting of anchor cable auxiliary installation equipment.
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In the process of rock bolt support for the roadway with floor heave, the rock bolt cannot reach the bottom of the borehole smoothly due to the influence of the collapse gravels around the borehole. ...In order to solve the problem of difficult rock bolt installation, the auxiliary installation device of rock bolt drilling was innovatively designed. At the same time, a new method of auxiliary bolt installation was put forward, in which a bit was installed at the bottom of the bolt to assist the bolt drilling. The drilling process of the bit was simulated by the co‐simulation of discrete element method (DEM) and multibody dynamics method (MBD). The axial resistance of the bit and the change law of the particles movement were studied under different motion parameters and structural parameters. It was found that the drilling performance of bit was directly related to the motion parameters and structure of bit. And the selection of gravel parameters in DEM was verified by experiments. The research results can provide technical guidance for bit structure design and the selection of motion parameters of bolt drilling auxiliary installation device, and can effectively improve the rock bolt installation efficiency.
A bit was installed at the bottom of the rock bolt to assist the rock bolt drilling. The drilling process of the bit was simulated by the co‐simulation of discrete element method and multibody dynamics method. The axial resistance of the bit and the change law of the particles movement were studied under different motion parameters and structural parameters.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
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