| Bolt supporting is a widely used supporting method in the coal mine because of its low investment costing, simple construction, and good supporting effect, etc.Design supporting parameter according to anchorage mechanism of anchoris the main ways to ensure the quality and the efficiency improvement of bolting supports, so studying the loading transfer rules of anchor rod and supporting parameters optimization have great significance to provide effective theoretical guidance for the design and construction.Firstly, load transfer function method is used for studying the distribution rule of drawing load along the length direction, then it is found thatThe distance of the loading along the anchor solid about the anchor rod under the effect of drawing force is limited. The value of loading is biggest at the head of anchor rod,and has a trend of decrease along the rod body.The transmission distance of loading along the rod is increasing with the increasing of drawing force, but the corresponding increasing distance is not the mainbearingof anchor rod loading. The increase of the loading on anchor rod is still mainly concentrating near the outcrop.Drawing load transfer ruleis combined with to analyze the influence factors of drawing force and resistance of anchor rod and the control zone of the anchor rod to the surrounding rock. The result shows that the value of the drawing force on anchor rod is in proportion to the diameter of the anchor solid, the biggest shear strength of anchoring layer, and within a certain range it is increasing with the increase of anchor rod anchorage length, when the anchorage length beyond this range, continue to increase the anchorage length of bolt has little influence on the ultimate tensile load pull.Secondly,the different supporting effect with different parameters in the surrounding rock issimulated,and then it is determined that The control range of anchor rod to surrounding rock is similar to a ellipsoid whose long axisis thereasonable anchorage length of anchor rod from the initial end anchorage, short axisis1/2～1/3of the reasonable anchorage length.On the basis of these, this paper deduced the formulas of the length and spacing of the rod supporting; at the same time,the limited element software is adopted to simulate the supporting effect with different strong coefficient of rock in roadway, then research and analyze the results of numerical simulation, so the best supporting parameters of surrounding rock with different grade are determined.Finally,theoretical calculation and numerical simulation were used respectively to determine the best supporting parameters of different solid rock based on the geological conditions of2141auxiliary transportation lane in HeBi Mine,and thendetermine the finally reasonable supporting parameters by comparing the two methods. After field application it is found the supporting effect is good, and it is proved that the parameter optimization scheme is rationality and feasibility. |
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