Research on Loose Circle Test of Deep Broken Roadway

To control the stability of deep well broken surrounding rock, single-hole sonic method is used to test the loose circle of-1180 east-rock main roadway and its damage range. The study indicates the loose circle is about 1.8 ~ 2.2 m, which is typical large loose circle. And its button is slightly larger than two sides’, right side slightly larger than left. The roadway rock has some engineering features of soft rock. The broken and expand deformation of loose circle does large, difficult to support. Combined support is usually used in this rock condition.