Experimental study on surrounding rock loosing circle by single-hole acoustic wave testing method

In order to determine the reasonable bolt support parameters and improve the stability of the surrounding rock of the roadway,the No.5203 roadway of Shanxi Jinzhuang coal mine was taken as the engineering background.Combined with the single-hole acoustic wave testing method and the formation mechanism of surrounding rock loose circle,the drilling position was reasonably arranged,the field surrounding rock loose circle range of No.5203 roadway was tested on site and the bolt support parameters design was carried out.Finally,the feasibility of the support design was verified by FLAC3D numerical simulation and on-site industrial test.Results showed that the loose zone of the No.5203 roadway ranged from 1.5 to 2.1 m.Comparing the results of the two simulation schemes,the maximum displacement of roadway’s sides was reduced by 9.5%,and the maximum displacement of the roof was reduced from 46.2 mm to 45.6 mm.The field measured the displacements of roadway’s sides and the roof were 30.3 mm and 46.5 mm respectively,and the displacement of the top plate was 46.5 mm.The field measurement and numerical simulation results were basically consistent.The single-hole acoustic wave testing method can quickly and accurately test the range of surrounding rock loose circle of roadway,and has good engineering practicability and superiority.