One-piece coal mine mobile refuge chamber with safety structure and less sealing risk based on FEA

In order to reduce the risk of sealing and improve the structural strength for a coal mine mobile refuge chamber, a new type of one-piece model was designed. Mechanical and mathematical calculation performed an important role. Calculated according to statics and relevant contents, the structure had the same total volume as the traditional segmented structure, but had shorter length, wider width and greater height. Those prevented the structure from stress or deformation failure. Some reinforcing ribs with enough moments of inertia were welded in the external shell. Because of the one-piece structure, this refuge chamber reduced the risk of sealing which was a serious problem of segmented structure. Impact load with 300 ms duration and 0.6 MPa over-pressure was settled. Explicit nonlinear dynamic analysis program was used to simulate the response of the refuge chamber. The maximum stress and the maximum displacement were obtained. The refuge chamber including blast airtight doors could meet the rigidity requirement. Weak parts of the chamber were the front and back end shell where bigger displacement values occurred than others. Thus, the calculation indicated that the refuge chamber could meet structural safety requirements. Based on the numerical analysis, suggestions were put forward for further resistance ability improvement. Only large inclined shaft with larger wellhead was suitable for this one-piece coal mine mobile refuge chamber.