| Abstract: | An alluvium with a sandy aquifer at the bottom, but lacking an effective impermeable layer between the sandy aquifer and bedrock is referred to as a special alluvial stratum. Impacted by the drainage of the aquifer due to mining activities, a shaft wall in this special alluvial stratum will be subject to a downward load by an additional vertical force which must be taken into consid-eration in the design of the shaft wall. The complexity of interaction between shaft wall and the surrounding walls makes it ex-tremely difficult to determine this additional vertical force. For a particular shaft wall in an extra-thick alluvium and assuming that the friction coefficient between shaft wall and stratum does not change with depth, an analysis of a numerical simulation of the stress within the shaft wall has been carried out. Growth and size of the additional vertical stress have been obtained, based on spe-cific values of the friction coefficient, the modulus of elasticity of the drainage layer and the thickness of the drainage layer. Subse-quently, the safety of shaft walls with different structural types was studied and a more suitable structural design, providing an im-portant basis for the design of shaft walls, is promoted. |
