Abstract:
To solve the problem of the instability of the deep pump chamber group, this paper takes the -890 level pump absorbing well chamber group of Daqiang coal mine as the engineering background. Through theoretical analysis, numerical simulation and field test, the reasons for the failure of the chamber group are analyzed, the effects of intensive design and traditional design on the stability control of surrounding rock are compared. Based on the characteristics of high constant resistance, high elongation and energy absorption of the NPR (Negative Poisson's Ratio) cable, the instability energy criterion of intersection under the NPR cable support is established, and the intensive control strategy of pump absorbing well with high prestressed NPR cable and three-dimensional truss as the core is put forward and applied in the field. The results show that high ground stress, low surrounding rock strength, dense distribution of chamber group, unreasonable excavation sequence of chamber group and inappropriate support are the main reasons for the failure of deep pump absorbing well chamber group. Compared with the traditional design, the intensive design simplifies the layout and construction procedure of the chamber, reduces the displacement and stress of the roadway, makes the plastic zone range smaller and more uniform, and eliminates the spatial effect. The deformation energy of the surrounding rock is released through the high constant resistance and large deformation of the NPR cable and the reserved gap between the truss and the surrounding rock, and the deformation of the surrounding rock is limited by applying high prestress to the NPR cable and the strength of the three-dimensional truss material, which can effectively ensure the stability of the roadway. The field application shows that this strategy can effectively ensure the stability of the chamber group, and the deformation of surrounding rock is controlled within 70 mm, which can provide a reference for similar projects.