Abstract
Pressure relief for roadways retained by roof cutting is essentially caused by stress transfer. In this paper, the stress transfer mechanism of 16011 tail entry with roof cutting in Zhaogu No.1 coal mine is studied from the following two aspects: the change of the tail entry surrounding the rock structure and the interaction between the roadway surrounding rock and supporting structures. It is found by numerical simulation that roof cutting can significantly reduce the magnitude of roadway roof stress, transferring the concentrated stress induced by excavation and mining away from the roadway, and forming an obvious triangle pressure relief area in front of the working face. In the early stage after mining, most of the overburden load is transferred downward through the immediate roof of the roadway. With the movement of overlying strata, the stress, initially transferred to the immediate roof strata, is gradually transferred to the gob, and the calculation formula and influence factors of the transferred stress are derived. In addition, through the establishment of the mechanical model and theoretical calculation of the key rock block of the main roof, the roadside support resistance required to ensure the stability of the main roof block is determined. The field monitoring shows that the lateral pressure coefficient of the roadside caved rocks is 0.36 and the constant resistance and large deformation anchor cable (CRLDAC) and the roadway temporary support play roles of conduction and control in the process of stress transfer, and effectively ensure the stability of surrounding rock during the service life of the retained gob-side entry by roof cutting (RGERC).
Highlights
Introduction iationsRetained gob-side entry by roof cutting (RGERC) is a new gob-side entry developed in recent years
Based on the idea of actively controlling the roof structure of the roadway and optimizing the stress environment of the surrounding rock, the constant resistance and large deformation anchor cable (CRLDAC) was adopted to strengthen the roadway roof, and the directional pre-split blasting technology was invented to cut off the roadway roof
It can be inferred that roof cutting will significantly affect the structhe structural continuity of the roadway roof strata, which will inevitably lead to the stress tural continuity of the roadway roof strata, which will inevitably lead to the stress transfer transfer and asymmetric distribution of surrounding rock stress
Summary
By analyzing shallow roof or two sides of thesurrounding roadway It did take the stress transfer path themechanism influence ofofroof cutting on the large structure change of roadway surrounding rock, of or large-scale surrounding rock into account. The mechanism of roof cutting on the pressure relief of roadway surrounding rock is revealed, and the technical and economic advantages of RGERC compared to the traditional GER are verified. The research results of this paper can fill the the temporary blank in theroadside research on pressure roof, it is concluded that the CRLDAC and support arerelief the key mechanisms of RGERC, further enrich the theory of stress and deformation control of re-and measures to control the stability of the surrounding rock of the retained roadway, tained gob-side and provide the roadway basis for can further improving the technology sufficient supportentry, resistance beside the ensure the stability of the mainofroof. Engineering Background mechanisms of RGERC, further enrich the theory of stress and deformation control of
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