Method for designing supporting parameters of transition support for mixed mining face of filling and fully-mechanized mining

A method for designing supporting parameters of a transition support for a mixed mining face of filling and fully-mechanized mining, comprising:

• first, determining a total length of a mixed mining working face and a length of a filling section working face according to requirements of a coal mining production capacity of the mixed mining working face and a filling capacity of the filling section working face;
• then, establishing a mixed mining numerical model of filling and fully-mechanized mining by using three-dimensional distinct element software according to tests of physical and mechanical parameters of coal rock in a working face area, and simulating and calculating a caving height of a roof of a transition section and a stress influence range of the transition section when a filling rate of a mined-out area of a filling section changes;
• based on a result of numerical simulation and calculation, performing curve fitting according to a correlation coefficient to obtain a functional relationship between the filling rate and the caving height and a functional relationship between the filling rate and the stress influence range of the transition section;
• and finally, determining parameters of a support of the transition section in combination with actual engineering geological parameters, wherein specific steps of the method are as follows:
• (1) determining the total length of the mixed mining working face and the length of the filling section working face according to the requirements of the coal mining production capacity of the mixed mining working face and the filling capacity of the filling section working face;
• (2) establishing the mixed mining numerical model of filling and fully-mechanized mining by using the three-dimensional distinct element software according to the tests of the physical and mechanical parameters of coal rock in the working face area;
• (3) under the premise that a mining height, the total length of the mixed mining working face, and the length of the filling section working face are determined, simulating the caving height H of the roof of the transition section and the stress influence range of the transition section when the filling rate of the filling section changes;
• (4) performing curve fitting according to the correlation coefficient to obtain the functional relationship between the filling rate and the caving height and the functional relationship between the filling rate and the stress influence range of the transition section;
• (5) calculating a caving height H′ of the transition section of the mixed mining working face according to a designed filling rate in practical engineering, and performing calculation using the following formula to determine supporting strength of the support of the transition section:
• F=γH′
• in which:
• γ is 2.5 MPa/100 m;
• and
• (6) calculating a stress influence range S′ of the transition section of the mixed mining working face according to the designed filling rate in practical engineering, and performing calculation using the following formula to determine a number of supports of the transition section:
• N
• ≥
• n
• =
• s
• ′
• a
• in which:
• N is a minimum positive integer greater than or equal to n, and
• α is a width of a single transition support.