Optimization analysis of ingate supporting structure under the condition of thick loose layer and thin bedrock

Aiming at the technical problems of ingate support under the condition of thick loose layer and thin bedrock, taking ingate of Dongfeng Well in Qinan Mine as the engineering background, we analyzed the original support design scheme by using FLAC3D, and explored the distribution law of stress field of ingate lining and the vertical displacement evolution law of overlying thin bedrock; we proposed the optimization design of ingate support structure, and verified the reliability of the optimized support scheme by numerical simulation and field measurement. The results show that: the original support scheme exhibits evident stress concentration in the ingate lining, excessive vertical settlement displacement in the overlying thin bedrock, and a high risk of support failure. Following optimization of the support scheme, there is a reduction observed in the maximum principal stress of the ingate lining, vertical settlement displacement in the overlying thin bedrock, and plastic zone volume of the support structure. On-site monitoring shows that the maximum monitoring pressure exerted by surrounding rock does not exceed 20% of the warning value, and the maximum tensile stress experienced by steel bars remains below their yield strength. These findings validate the reliability of the optimized support scheme.