Study on thetechnology of non- through pre-split and roof-cutting in overlying rock of fully mechanized caving face

To carry out effective comprehensive prevention and control of rock burst, taking Tangkou Coal Mine as an example, theoretical analysis, numerical simulation and engineering practice were used to study the mechanism of roof-cutting and pressure relief of fully mechanized caving face in deep well. It is found that the thickness of the suspended roof of the key layer is an important factor affecting the release of key energy. Based on this, the non - through pre - split and roof - cutting technology is proposed to reveal the mechanical mechanism of the non-through pre-split and roof-cutting of the key layer in fully mechanized caving mining. By creating pre - split surfaces in the key layer, the length and stress concentration of the cantilever beam can be effectively reduced, thereby controlling the release of energy and reducing the risk of rock burst. The value of the spatial parameter of the non - through pre - split slit is mastered, which provides the theoretical basis for the implementation of the technology. A 3D numerical model of non-through pre-split roof cutting was established. The results show that the effect is most significant when the combined fan-shaped holes with roof cutting angles of 45°, 60° and 75° are adopted and the pre-split roof-cutting spacing is 10 m. This technology can effectively reduce the probability of rockburst and promote the safety and high efficiency of pre-split and roof-cutting blasting.